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annotate en/hook.tex @ 307:fb5c0d56d7f1

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Fix test 'tour'.

Executing 'tour' test now creates some files in /tmp to store the
revision numbers as they are created on the fly and appear in the output
files. When SVG files are to be converted to PNG or EPS files within the
Makefile, a tool 'fixsvg' will be invoked to substitute some placeholder
markup by the real version number which fits to the test output, before
the final conversion takes place.
author Guido Ostkamp <hg@ostkamp.fastmail.fm>
date Wed Aug 20 22:15:35 2008 +0200 (2008-08-20)
parents 5f35a333ab9b
children a168daed199b
rev   line source
bos@34 1 \chapter{Handling repository events with hooks}
bos@34 2 \label{chap:hook}
bos@34 3
bos@34 4 Mercurial offers a powerful mechanism to let you perform automated
bos@34 5 actions in response to events that occur in a repository. In some
bos@34 6 cases, you can even control Mercurial's response to those events.
bos@34 7
bos@34 8 The name Mercurial uses for one of these actions is a \emph{hook}.
bos@34 9 Hooks are called ``triggers'' in some revision control systems, but
bos@34 10 the two names refer to the same idea.
bos@34 11
bos@38 12 \section{An overview of hooks in Mercurial}
bos@38 13
bos@41 14 Here is a brief list of the hooks that Mercurial supports. We will
bos@41 15 revisit each of these hooks in more detail later, in
bos@41 16 section~\ref{sec:hook:ref}.
bos@41 17
bos@38 18 \begin{itemize}
bos@38 19 \item[\small\hook{changegroup}] This is run after a group of
bos@41 20 changesets has been brought into the repository from elsewhere.
bos@38 21 \item[\small\hook{commit}] This is run after a new changeset has been
bos@41 22 created in the local repository.
bos@38 23 \item[\small\hook{incoming}] This is run once for each new changeset
bos@38 24 that is brought into the repository from elsewhere. Notice the
bos@38 25 difference from \hook{changegroup}, which is run once per
bos@41 26 \emph{group} of changesets brought in.
bos@38 27 \item[\small\hook{outgoing}] This is run after a group of changesets
bos@41 28 has been transmitted from this repository.
bos@38 29 \item[\small\hook{prechangegroup}] This is run before starting to
bos@41 30 bring a group of changesets into the repository.
bos@41 31 \item[\small\hook{precommit}] Controlling. This is run before starting
bos@41 32 a commit.
bos@41 33 \item[\small\hook{preoutgoing}] Controlling. This is run before
bos@41 34 starting to transmit a group of changesets from this repository.
bos@41 35 \item[\small\hook{pretag}] Controlling. This is run before creating a tag.
bos@41 36 \item[\small\hook{pretxnchangegroup}] Controlling. This is run after a
bos@41 37 group of changesets has been brought into the local repository from
bos@41 38 another, but before the transaction completes that will make the
bos@41 39 changes permanent in the repository.
bos@41 40 \item[\small\hook{pretxncommit}] Controlling. This is run after a new
bos@41 41 changeset has been created in the local repository, but before the
bos@41 42 transaction completes that will make it permanent.
bos@41 43 \item[\small\hook{preupdate}] Controlling. This is run before starting
bos@41 44 an update or merge of the working directory.
bos@38 45 \item[\small\hook{tag}] This is run after a tag is created.
bos@38 46 \item[\small\hook{update}] This is run after an update or merge of the
bos@38 47 working directory has finished.
bos@38 48 \end{itemize}
bos@41 49 Each of the hooks whose description begins with the word
bos@41 50 ``Controlling'' has the ability to determine whether an activity can
bos@41 51 proceed. If the hook succeeds, the activity may proceed; if it fails,
bos@41 52 the activity is either not permitted or undone, depending on the hook.
bos@38 53
bos@38 54 \section{Hooks and security}
bos@38 55
bos@38 56 \subsection{Hooks are run with your privileges}
bos@38 57
bos@38 58 When you run a Mercurial command in a repository, and the command
bos@41 59 causes a hook to run, that hook runs on \emph{your} system, under
bos@41 60 \emph{your} user account, with \emph{your} privilege level. Since
bos@41 61 hooks are arbitrary pieces of executable code, you should treat them
bos@41 62 with an appropriate level of suspicion. Do not install a hook unless
bos@41 63 you are confident that you know who created it and what it does.
bos@38 64
bos@38 65 In some cases, you may be exposed to hooks that you did not install
bos@38 66 yourself. If you work with Mercurial on an unfamiliar system,
bos@38 67 Mercurial will run hooks defined in that system's global \hgrc\ file.
bos@38 68
bos@38 69 If you are working with a repository owned by another user, Mercurial
bos@41 70 can run hooks defined in that user's repository, but it will still run
bos@41 71 them as ``you''. For example, if you \hgcmd{pull} from that
bos@41 72 repository, and its \sfilename{.hg/hgrc} defines a local
bos@41 73 \hook{outgoing} hook, that hook will run under your user account, even
bos@41 74 though you don't own that repository.
bos@38 75
bos@38 76 \begin{note}
bos@38 77 This only applies if you are pulling from a repository on a local or
bos@38 78 network filesystem. If you're pulling over http or ssh, any
bos@41 79 \hook{outgoing} hook will run under whatever account is executing
bos@41 80 the server process, on the server.
bos@38 81 \end{note}
bos@38 82
bos@38 83 XXX To see what hooks are defined in a repository, use the
bos@38 84 \hgcmdargs{config}{hooks} command. If you are working in one
bos@38 85 repository, but talking to another that you do not own (e.g.~using
bos@38 86 \hgcmd{pull} or \hgcmd{incoming}), remember that it is the other
bos@38 87 repository's hooks you should be checking, not your own.
bos@38 88
bos@38 89 \subsection{Hooks do not propagate}
bos@38 90
bos@38 91 In Mercurial, hooks are not revision controlled, and do not propagate
bos@38 92 when you clone, or pull from, a repository. The reason for this is
bos@38 93 simple: a hook is a completely arbitrary piece of executable code. It
bos@38 94 runs under your user identity, with your privilege level, on your
bos@38 95 machine.
bos@38 96
bos@38 97 It would be extremely reckless for any distributed revision control
bos@38 98 system to implement revision-controlled hooks, as this would offer an
bos@38 99 easily exploitable way to subvert the accounts of users of the
bos@38 100 revision control system.
bos@38 101
bos@38 102 Since Mercurial does not propagate hooks, if you are collaborating
bos@38 103 with other people on a common project, you should not assume that they
bos@38 104 are using the same Mercurial hooks as you are, or that theirs are
bos@38 105 correctly configured. You should document the hooks you expect people
bos@38 106 to use.
bos@38 107
bos@38 108 In a corporate intranet, this is somewhat easier to control, as you
bos@38 109 can for example provide a ``standard'' installation of Mercurial on an
bos@38 110 NFS filesystem, and use a site-wide \hgrc\ file to define hooks that
bos@38 111 all users will see. However, this too has its limits; see below.
bos@38 112
bos@38 113 \subsection{Hooks can be overridden}
bos@38 114
bos@38 115 Mercurial allows you to override a hook definition by redefining the
bos@38 116 hook. You can disable it by setting its value to the empty string, or
bos@38 117 change its behaviour as you wish.
bos@38 118
bos@38 119 If you deploy a system-~or site-wide \hgrc\ file that defines some
bos@38 120 hooks, you should thus understand that your users can disable or
bos@38 121 override those hooks.
bos@38 122
bos@38 123 \subsection{Ensuring that critical hooks are run}
bos@38 124
bos@38 125 Sometimes you may want to enforce a policy that you do not want others
bos@38 126 to be able to work around. For example, you may have a requirement
bos@38 127 that every changeset must pass a rigorous set of tests. Defining this
bos@38 128 requirement via a hook in a site-wide \hgrc\ won't work for remote
bos@38 129 users on laptops, and of course local users can subvert it at will by
bos@38 130 overriding the hook.
bos@38 131
bos@38 132 Instead, you can set up your policies for use of Mercurial so that
bos@38 133 people are expected to propagate changes through a well-known
bos@38 134 ``canonical'' server that you have locked down and configured
bos@38 135 appropriately.
bos@38 136
bos@38 137 One way to do this is via a combination of social engineering and
bos@38 138 technology. Set up a restricted-access account; users can push
bos@38 139 changes over the network to repositories managed by this account, but
bos@38 140 they cannot log into the account and run normal shell commands. In
bos@38 141 this scenario, a user can commit a changeset that contains any old
bos@38 142 garbage they want.
bos@38 143
bos@38 144 When someone pushes a changeset to the server that everyone pulls
bos@38 145 from, the server will test the changeset before it accepts it as
bos@38 146 permanent, and reject it if it fails to pass the test suite. If
bos@38 147 people only pull changes from this filtering server, it will serve to
bos@38 148 ensure that all changes that people pull have been automatically
bos@38 149 vetted.
bos@38 150
bos@134 151 \section{Care with \texttt{pretxn} hooks in a shared-access repository}
bos@41 152
wbunaarfubss@247 153 If you want to use hooks to do some automated work in a repository
bos@54 154 that a number of people have shared access to, you need to be careful
bos@41 155 in how you do this.
bos@41 156
bos@41 157 Mercurial only locks a repository when it is writing to the
bos@41 158 repository, and only the parts of Mercurial that write to the
bos@41 159 repository pay attention to locks. Write locks are necessary to
bos@41 160 prevent multiple simultaneous writers from scribbling on each other's
bos@41 161 work, corrupting the repository.
bos@41 162
bos@41 163 Because Mercurial is careful with the order in which it reads and
bos@41 164 writes data, it does not need to acquire a lock when it wants to read
bos@41 165 data from the repository. The parts of Mercurial that read from the
bos@41 166 repository never pay attention to locks. This lockless reading scheme
bos@41 167 greatly increases performance and concurrency.
bos@41 168
bos@41 169 With great performance comes a trade-off, though, one which has the
bos@41 170 potential to cause you trouble unless you're aware of it. To describe
bos@41 171 this requires a little detail about how Mercurial adds changesets to a
bos@41 172 repository and reads those changes.
bos@41 173
bos@41 174 When Mercurial \emph{writes} metadata, it writes it straight into the
bos@41 175 destination file. It writes file data first, then manifest data
bos@41 176 (which contains pointers to the new file data), then changelog data
bos@41 177 (which contains pointers to the new manifest data). Before the first
bos@41 178 write to each file, it stores a record of where the end of the file
bos@41 179 was in its transaction log. If the transaction must be rolled back,
bos@54 180 Mercurial simply truncates each file back to the size it was before the
bos@41 181 transaction began.
bos@41 182
bos@41 183 When Mercurial \emph{reads} metadata, it reads the changelog first,
bos@41 184 then everything else. Since a reader will only access parts of the
bos@41 185 manifest or file metadata that it can see in the changelog, it can
bos@41 186 never see partially written data.
bos@41 187
bos@41 188 Some controlling hooks (\hook{pretxncommit} and
bos@41 189 \hook{pretxnchangegroup}) run when a transaction is almost complete.
bos@41 190 All of the metadata has been written, but Mercurial can still roll the
bos@41 191 transaction back and cause the newly-written data to disappear.
bos@41 192
bos@134 193 If one of these hooks runs for long, it opens a window of time during
bos@134 194 which a reader can see the metadata for changesets that are not yet
bos@134 195 permanent, and should not be thought of as ``really there''. The
bos@134 196 longer the hook runs, the longer that window is open.
bos@134 197
bos@134 198 \subsection{The problem illustrated}
bos@134 199
bos@134 200 In principle, a good use for the \hook{pretxnchangegroup} hook would
bos@134 201 be to automatically build and test incoming changes before they are
bos@134 202 accepted into a central repository. This could let you guarantee that
bos@134 203 nobody can push changes to this repository that ``break the build''.
bos@134 204 But if a client can pull changes while they're being tested, the
bos@134 205 usefulness of the test is zero; an unsuspecting someone can pull
bos@134 206 untested changes, potentially breaking their build.
bos@134 207
bos@134 208 The safest technological answer to this challenge is to set up such a
bos@134 209 ``gatekeeper'' repository as \emph{unidirectional}. Let it take
bos@134 210 changes pushed in from the outside, but do not allow anyone to pull
bos@134 211 changes from it (use the \hook{preoutgoing} hook to lock it down).
bos@134 212 Configure a \hook{changegroup} hook so that if a build or test
bos@134 213 succeeds, the hook will push the new changes out to another repository
bos@134 214 that people \emph{can} pull from.
bos@134 215
bos@134 216 In practice, putting a centralised bottleneck like this in place is
bos@134 217 not often a good idea, and transaction visibility has nothing to do
bos@134 218 with the problem. As the size of a project---and the time it takes to
bos@134 219 build and test---grows, you rapidly run into a wall with this ``try
bos@134 220 before you buy'' approach, where you have more changesets to test than
bos@134 221 time in which to deal with them. The inevitable result is frustration
bos@134 222 on the part of all involved.
bos@134 223
bos@134 224 An approach that scales better is to get people to build and test
bos@134 225 before they push, then run automated builds and tests centrally
bos@134 226 \emph{after} a push, to be sure all is well. The advantage of this
bos@134 227 approach is that it does not impose a limit on the rate at which the
bos@134 228 repository can accept changes.
bos@41 229
bos@34 230 \section{A short tutorial on using hooks}
bos@34 231 \label{sec:hook:simple}
bos@34 232
bos@34 233 It is easy to write a Mercurial hook. Let's start with a hook that
bos@34 234 runs when you finish a \hgcmd{commit}, and simply prints the hash of
bos@34 235 the changeset you just created. The hook is called \hook{commit}.
bos@34 236
bos@34 237 \begin{figure}[ht]
bos@34 238 \interaction{hook.simple.init}
bos@34 239 \caption{A simple hook that runs when a changeset is committed}
bos@34 240 \label{ex:hook:init}
bos@34 241 \end{figure}
bos@34 242
bos@34 243 All hooks follow the pattern in example~\ref{ex:hook:init}. You add
bos@34 244 an entry to the \rcsection{hooks} section of your \hgrc\. On the left
bos@34 245 is the name of the event to trigger on; on the right is the action to
bos@34 246 take. As you can see, you can run an arbitrary shell command in a
bos@34 247 hook. Mercurial passes extra information to the hook using
bos@34 248 environment variables (look for \envar{HG\_NODE} in the example).
bos@34 249
bos@34 250 \subsection{Performing multiple actions per event}
bos@34 251
bos@34 252 Quite often, you will want to define more than one hook for a
bos@34 253 particular kind of event, as shown in example~\ref{ex:hook:ext}.
bos@34 254 Mercurial lets you do this by adding an \emph{extension} to the end of
bos@34 255 a hook's name. You extend a hook's name by giving the name of the
bos@34 256 hook, followed by a full stop (the ``\texttt{.}'' character), followed
bos@34 257 by some more text of your choosing. For example, Mercurial will run
bos@34 258 both \texttt{commit.foo} and \texttt{commit.bar} when the
bos@34 259 \texttt{commit} event occurs.
bos@34 260
bos@34 261 \begin{figure}[ht]
bos@34 262 \interaction{hook.simple.ext}
bos@34 263 \caption{Defining a second \hook{commit} hook}
bos@34 264 \label{ex:hook:ext}
bos@34 265 \end{figure}
bos@34 266
bos@34 267 To give a well-defined order of execution when there are multiple
bos@34 268 hooks defined for an event, Mercurial sorts hooks by extension, and
bos@34 269 executes the hook commands in this sorted order. In the above
bos@34 270 example, it will execute \texttt{commit.bar} before
bos@34 271 \texttt{commit.foo}, and \texttt{commit} before both.
bos@34 272
bos@34 273 It is a good idea to use a somewhat descriptive extension when you
bos@34 274 define a new hook. This will help you to remember what the hook was
bos@34 275 for. If the hook fails, you'll get an error message that contains the
bos@34 276 hook name and extension, so using a descriptive extension could give
bos@34 277 you an immediate hint as to why the hook failed (see
bos@34 278 section~\ref{sec:hook:perm} for an example).
bos@34 279
bos@34 280 \subsection{Controlling whether an activity can proceed}
bos@34 281 \label{sec:hook:perm}
bos@34 282
bos@34 283 In our earlier examples, we used the \hook{commit} hook, which is
bos@34 284 run after a commit has completed. This is one of several Mercurial
bos@34 285 hooks that run after an activity finishes. Such hooks have no way of
bos@34 286 influencing the activity itself.
bos@34 287
bos@34 288 Mercurial defines a number of events that occur before an activity
bos@34 289 starts; or after it starts, but before it finishes. Hooks that
bos@34 290 trigger on these events have the added ability to choose whether the
bos@34 291 activity can continue, or will abort.
bos@34 292
bos@34 293 The \hook{pretxncommit} hook runs after a commit has all but
bos@34 294 completed. In other words, the metadata representing the changeset
bos@34 295 has been written out to disk, but the transaction has not yet been
bos@34 296 allowed to complete. The \hook{pretxncommit} hook has the ability to
bos@34 297 decide whether the transaction can complete, or must be rolled back.
bos@34 298
bos@34 299 If the \hook{pretxncommit} hook exits with a status code of zero, the
bos@34 300 transaction is allowed to complete; the commit finishes; and the
bos@34 301 \hook{commit} hook is run. If the \hook{pretxncommit} hook exits with
bos@34 302 a non-zero status code, the transaction is rolled back; the metadata
bos@34 303 representing the changeset is erased; and the \hook{commit} hook is
bos@34 304 not run.
bos@34 305
bos@34 306 \begin{figure}[ht]
bos@34 307 \interaction{hook.simple.pretxncommit}
bos@34 308 \caption{Using the \hook{pretxncommit} hook to control commits}
bos@34 309 \label{ex:hook:pretxncommit}
bos@34 310 \end{figure}
bos@34 311
bos@34 312 The hook in example~\ref{ex:hook:pretxncommit} checks that a commit
bos@34 313 comment contains a bug ID. If it does, the commit can complete. If
bos@34 314 not, the commit is rolled back.
bos@34 315
bos@37 316 \section{Writing your own hooks}
bos@37 317
bos@37 318 When you are writing a hook, you might find it useful to run Mercurial
bos@37 319 either with the \hggopt{-v} option, or the \rcitem{ui}{verbose} config
bos@37 320 item set to ``true''. When you do so, Mercurial will print a message
bos@37 321 before it calls each hook.
bos@37 322
bos@37 323 \subsection{Choosing how your hook should run}
bos@37 324 \label{sec:hook:lang}
bos@34 325
bos@34 326 You can write a hook either as a normal program---typically a shell
bos@37 327 script---or as a Python function that is executed within the Mercurial
bos@34 328 process.
bos@34 329
bos@34 330 Writing a hook as an external program has the advantage that it
bos@34 331 requires no knowledge of Mercurial's internals. You can call normal
bos@34 332 Mercurial commands to get any added information you need. The
bos@34 333 trade-off is that external hooks are slower than in-process hooks.
bos@34 334
bos@34 335 An in-process Python hook has complete access to the Mercurial API,
bos@34 336 and does not ``shell out'' to another process, so it is inherently
bos@34 337 faster than an external hook. It is also easier to obtain much of the
bos@34 338 information that a hook requires by using the Mercurial API than by
bos@34 339 running Mercurial commands.
bos@34 340
bos@34 341 If you are comfortable with Python, or require high performance,
bos@34 342 writing your hooks in Python may be a good choice. However, when you
bos@34 343 have a straightforward hook to write and you don't need to care about
bos@34 344 performance (probably the majority of hooks), a shell script is
bos@34 345 perfectly fine.
bos@34 346
bos@37 347 \subsection{Hook parameters}
bos@34 348 \label{sec:hook:param}
bos@34 349
bos@34 350 Mercurial calls each hook with a set of well-defined parameters. In
bos@34 351 Python, a parameter is passed as a keyword argument to your hook
bos@34 352 function. For an external program, a parameter is passed as an
bos@34 353 environment variable.
bos@34 354
bos@34 355 Whether your hook is written in Python or as a shell script, the
bos@37 356 hook-specific parameter names and values will be the same. A boolean
bos@37 357 parameter will be represented as a boolean value in Python, but as the
bos@37 358 number 1 (for ``true'') or 0 (for ``false'') as an environment
bos@37 359 variable for an external hook. If a hook parameter is named
bos@37 360 \texttt{foo}, the keyword argument for a Python hook will also be
bos@51 361 named \texttt{foo}, while the environment variable for an external
bos@51 362 hook will be named \texttt{HG\_FOO}.
bos@37 363
bos@37 364 \subsection{Hook return values and activity control}
bos@37 365
bos@37 366 A hook that executes successfully must exit with a status of zero if
bos@37 367 external, or return boolean ``false'' if in-process. Failure is
bos@37 368 indicated with a non-zero exit status from an external hook, or an
bos@37 369 in-process hook returning boolean ``true''. If an in-process hook
bos@37 370 raises an exception, the hook is considered to have failed.
bos@37 371
bos@37 372 For a hook that controls whether an activity can proceed, zero/false
bos@37 373 means ``allow'', while non-zero/true/exception means ``deny''.
bos@37 374
bos@37 375 \subsection{Writing an external hook}
bos@37 376
bos@37 377 When you define an external hook in your \hgrc\ and the hook is run,
bos@37 378 its value is passed to your shell, which interprets it. This means
bos@37 379 that you can use normal shell constructs in the body of the hook.
bos@37 380
bos@37 381 An executable hook is always run with its current directory set to a
bos@37 382 repository's root directory.
bos@37 383
bos@37 384 Each hook parameter is passed in as an environment variable; the name
bos@37 385 is upper-cased, and prefixed with the string ``\texttt{HG\_}''.
bos@37 386
bos@37 387 With the exception of hook parameters, Mercurial does not set or
bos@37 388 modify any environment variables when running a hook. This is useful
bos@37 389 to remember if you are writing a site-wide hook that may be run by a
bos@37 390 number of different users with differing environment variables set.
bos@37 391 In multi-user situations, you should not rely on environment variables
bos@37 392 being set to the values you have in your environment when testing the
bos@37 393 hook.
bos@37 394
bos@37 395 \subsection{Telling Mercurial to use an in-process hook}
bos@37 396
bos@37 397 The \hgrc\ syntax for defining an in-process hook is slightly
bos@37 398 different than for an executable hook. The value of the hook must
bos@37 399 start with the text ``\texttt{python:}'', and continue with the
bos@37 400 fully-qualified name of a callable object to use as the hook's value.
bos@37 401
bos@37 402 The module in which a hook lives is automatically imported when a hook
bos@37 403 is run. So long as you have the module name and \envar{PYTHONPATH}
bos@37 404 right, it should ``just work''.
bos@37 405
bos@37 406 The following \hgrc\ example snippet illustrates the syntax and
bos@37 407 meaning of the notions we just described.
bos@37 408 \begin{codesample2}
bos@37 409 [hooks]
bos@37 410 commit.example = python:mymodule.submodule.myhook
bos@37 411 \end{codesample2}
bos@37 412 When Mercurial runs the \texttt{commit.example} hook, it imports
bos@37 413 \texttt{mymodule.submodule}, looks for the callable object named
bos@37 414 \texttt{myhook}, and calls it.
bos@37 415
bos@37 416 \subsection{Writing an in-process hook}
bos@37 417
bos@37 418 The simplest in-process hook does nothing, but illustrates the basic
bos@37 419 shape of the hook API:
bos@37 420 \begin{codesample2}
bos@37 421 def myhook(ui, repo, **kwargs):
bos@37 422 pass
bos@37 423 \end{codesample2}
bos@37 424 The first argument to a Python hook is always a
bos@37 425 \pymodclass{mercurial.ui}{ui} object. The second is a repository object;
bos@37 426 at the moment, it is always an instance of
bos@37 427 \pymodclass{mercurial.localrepo}{localrepository}. Following these two
bos@37 428 arguments are other keyword arguments. Which ones are passed in
bos@37 429 depends on the hook being called, but a hook can ignore arguments it
bos@37 430 doesn't care about by dropping them into a keyword argument dict, as
bos@37 431 with \texttt{**kwargs} above.
bos@34 432
bos@44 433 \section{Some hook examples}
bos@44 434
bos@49 435 \subsection{Writing meaningful commit messages}
bos@49 436
bos@49 437 It's hard to imagine a useful commit message being very short. The
bos@155 438 simple \hook{pretxncommit} hook of figure~\ref{ex:hook:msglen.go}
bos@49 439 will prevent you from committing a changeset with a message that is
bos@49 440 less than ten bytes long.
bos@49 441
bos@49 442 \begin{figure}[ht]
bos@155 443 \interaction{hook.msglen.go}
bos@49 444 \caption{A hook that forbids overly short commit messages}
bos@155 445 \label{ex:hook:msglen.go}
bos@49 446 \end{figure}
bos@49 447
bos@49 448 \subsection{Checking for trailing whitespace}
bos@44 449
bos@44 450 An interesting use of a commit-related hook is to help you to write
bos@44 451 cleaner code. A simple example of ``cleaner code'' is the dictum that
bos@44 452 a change should not add any new lines of text that contain ``trailing
bos@44 453 whitespace''. Trailing whitespace is a series of space and tab
bos@44 454 characters at the end of a line of text. In most cases, trailing
bos@44 455 whitespace is unnecessary, invisible noise, but it is occasionally
bos@49 456 problematic, and people often prefer to get rid of it.
bos@44 457
bos@44 458 You can use either the \hook{precommit} or \hook{pretxncommit} hook to
bos@44 459 tell whether you have a trailing whitespace problem. If you use the
bos@44 460 \hook{precommit} hook, the hook will not know which files you are
bos@44 461 committing, so it will have to check every modified file in the
bos@44 462 repository for trailing white space. If you want to commit a change
bos@44 463 to just the file \filename{foo}, but the file \filename{bar} contains
bos@44 464 trailing whitespace, doing a check in the \hook{precommit} hook will
bos@44 465 prevent you from committing \filename{foo} due to the problem with
bos@44 466 \filename{bar}. This doesn't seem right.
bos@44 467
bos@44 468 Should you choose the \hook{pretxncommit} hook, the check won't occur
bos@44 469 until just before the transaction for the commit completes. This will
bos@44 470 allow you to check for problems only the exact files that are being
bos@44 471 committed. However, if you entered the commit message interactively
bos@44 472 and the hook fails, the transaction will roll back; you'll have to
bos@44 473 re-enter the commit message after you fix the trailing whitespace and
bos@44 474 run \hgcmd{commit} again.
bos@44 475
bos@44 476 \begin{figure}[ht]
bos@44 477 \interaction{hook.ws.simple}
bos@44 478 \caption{A simple hook that checks for trailing whitespace}
bos@44 479 \label{ex:hook:ws.simple}
bos@44 480 \end{figure}
bos@44 481
bos@44 482 Figure~\ref{ex:hook:ws.simple} introduces a simple \hook{pretxncommit}
bos@44 483 hook that checks for trailing whitespace. This hook is short, but not
bos@44 484 very helpful. It exits with an error status if a change adds a line
bos@44 485 with trailing whitespace to any file, but does not print any
bos@49 486 information that might help us to identify the offending file or
bos@49 487 line. It also has the nice property of not paying attention to
bos@49 488 unmodified lines; only lines that introduce new trailing whitespace
bos@49 489 cause problems.
bos@49 490
bos@49 491 \begin{figure}[ht]
bos@49 492 \interaction{hook.ws.better}
bos@49 493 \caption{A better trailing whitespace hook}
bos@49 494 \label{ex:hook:ws.better}
bos@49 495 \end{figure}
bos@49 496
bos@49 497 The example of figure~\ref{ex:hook:ws.better} is much more complex,
bos@49 498 but also more useful. It parses a unified diff to see if any lines
bos@49 499 add trailing whitespace, and prints the name of the file and the line
bos@49 500 number of each such occurrence. Even better, if the change adds
bos@49 501 trailing whitespace, this hook saves the commit comment and prints the
bos@49 502 name of the save file before exiting and telling Mercurial to roll the
bos@49 503 transaction back, so you can use
bos@49 504 \hgcmdargs{commit}{\hgopt{commit}{-l}~\emph{filename}} to reuse the
bos@49 505 saved commit message once you've corrected the problem.
bos@49 506
bos@49 507 As a final aside, note in figure~\ref{ex:hook:ws.better} the use of
bos@49 508 \command{perl}'s in-place editing feature to get rid of trailing
bos@49 509 whitespace from a file. This is concise and useful enough that I will
bos@49 510 reproduce it here.
bos@49 511 \begin{codesample2}
bos@54 512 perl -pi -e 's,\\s+\$,,' filename
bos@49 513 \end{codesample2}
bos@49 514
bos@49 515 \section{Bundled hooks}
bos@49 516
bos@49 517 Mercurial ships with several bundled hooks. You can find them in the
bos@49 518 \dirname{hgext} directory of a Mercurial source tree. If you are
bos@49 519 using a Mercurial binary package, the hooks will be located in the
bos@49 520 \dirname{hgext} directory of wherever your package installer put
bos@49 521 Mercurial.
bos@49 522
bos@49 523 \subsection{\hgext{acl}---access control for parts of a repository}
bos@49 524
bos@49 525 The \hgext{acl} extension lets you control which remote users are
bos@49 526 allowed to push changesets to a networked server. You can protect any
bos@49 527 portion of a repository (including the entire repo), so that a
bos@49 528 specific remote user can push changes that do not affect the protected
bos@49 529 portion.
bos@49 530
bos@49 531 This extension implements access control based on the identity of the
bos@49 532 user performing a push, \emph{not} on who committed the changesets
bos@62 533 they're pushing. It makes sense to use this hook only if you have a
bos@62 534 locked-down server environment that authenticates remote users, and
bos@62 535 you want to be sure that only specific users are allowed to push
bos@62 536 changes to that server.
bos@62 537
bos@62 538 \subsubsection{Configuring the \hook{acl} hook}
bos@62 539
bos@62 540 In order to manage incoming changesets, the \hgext{acl} hook must be
bos@62 541 used as a \hook{pretxnchangegroup} hook. This lets it see which files
bos@62 542 are modified by each incoming changeset, and roll back a group of
bos@62 543 changesets if they modify ``forbidden'' files. Example:
bos@62 544 \begin{codesample2}
bos@62 545 [hooks]
bos@62 546 pretxnchangegroup.acl = python:hgext.acl.hook
bos@62 547 \end{codesample2}
bos@62 548
bos@62 549 The \hgext{acl} extension is configured using three sections.
bos@62 550
bos@62 551 The \rcsection{acl} section has only one entry, \rcitem{acl}{sources},
bos@62 552 which lists the sources of incoming changesets that the hook should
bos@62 553 pay attention to. You don't normally need to configure this section.
bos@62 554 \begin{itemize}
bos@64 555 \item[\rcitem{acl}{serve}] Control incoming changesets that are arriving
bos@62 556 from a remote repository over http or ssh. This is the default
bos@62 557 value of \rcitem{acl}{sources}, and usually the only setting you'll
bos@62 558 need for this configuration item.
bos@64 559 \item[\rcitem{acl}{pull}] Control incoming changesets that are
bos@64 560 arriving via a pull from a local repository.
bos@64 561 \item[\rcitem{acl}{push}] Control incoming changesets that are
bos@64 562 arriving via a push from a local repository.
bos@64 563 \item[\rcitem{acl}{bundle}] Control incoming changesets that are
bos@64 564 arriving from another repository via a bundle.
bos@62 565 \end{itemize}
bos@62 566
bos@62 567 The \rcsection{acl.allow} section controls the users that are allowed to
bos@62 568 add changesets to the repository. If this section is not present, all
bos@62 569 users that are not explicitly denied are allowed. If this section is
bos@62 570 present, all users that are not explicitly allowed are denied (so an
bos@62 571 empty section means that all users are denied).
bos@62 572
bos@62 573 The \rcsection{acl.deny} section determines which users are denied
bos@62 574 from adding changesets to the repository. If this section is not
bos@62 575 present or is empty, no users are denied.
bos@62 576
bos@62 577 The syntaxes for the \rcsection{acl.allow} and \rcsection{acl.deny}
bos@62 578 sections are identical. On the left of each entry is a glob pattern
bos@62 579 that matches files or directories, relative to the root of the
bos@62 580 repository; on the right, a user name.
bos@62 581
bos@62 582 In the following example, the user \texttt{docwriter} can only push
bos@62 583 changes to the \dirname{docs} subtree of the repository, while
bos@62 584 \texttt{intern} can push changes to any file or directory except
bos@62 585 \dirname{source/sensitive}.
bos@62 586 \begin{codesample2}
bos@62 587 [acl.allow]
bos@62 588 docs/** = docwriter
bos@62 589
bos@62 590 [acl.deny]
bos@62 591 source/sensitive/** = intern
bos@62 592 \end{codesample2}
bos@62 593
bos@62 594 \subsubsection{Testing and troubleshooting}
bos@62 595
bos@62 596 If you want to test the \hgext{acl} hook, run it with Mercurial's
bos@62 597 debugging output enabled. Since you'll probably be running it on a
bos@62 598 server where it's not convenient (or sometimes possible) to pass in
bos@62 599 the \hggopt{--debug} option, don't forget that you can enable
bos@62 600 debugging output in your \hgrc:
bos@62 601 \begin{codesample2}
bos@62 602 [ui]
bos@62 603 debug = true
bos@62 604 \end{codesample2}
bos@62 605 With this enabled, the \hgext{acl} hook will print enough information
bos@62 606 to let you figure out why it is allowing or forbidding pushes from
bos@62 607 specific users.
bos@62 608
bos@62 609 \subsection{\hgext{bugzilla}---integration with Bugzilla}
bos@62 610
bos@62 611 The \hgext{bugzilla} extension adds a comment to a Bugzilla bug
bos@62 612 whenever it finds a reference to that bug ID in a commit comment. You
bos@62 613 can install this hook on a shared server, so that any time a remote
bos@62 614 user pushes changes to this server, the hook gets run.
bos@62 615
bos@62 616 It adds a comment to the bug that looks like this (you can configure
bos@62 617 the contents of the comment---see below):
bos@62 618 \begin{codesample2}
bos@62 619 Changeset aad8b264143a, made by Joe User <joe.user@domain.com> in
bos@62 620 the frobnitz repository, refers to this bug.
bos@62 621
bos@62 622 For complete details, see
bos@62 623 http://hg.domain.com/frobnitz?cmd=changeset;node=aad8b264143a
bos@62 624
bos@62 625 Changeset description:
bos@62 626 Fix bug 10483 by guarding against some NULL pointers
bos@62 627 \end{codesample2}
bos@62 628 The value of this hook is that it automates the process of updating a
bos@62 629 bug any time a changeset refers to it. If you configure the hook
bos@62 630 properly, it makes it easy for people to browse straight from a
bos@62 631 Bugzilla bug to a changeset that refers to that bug.
bos@62 632
bos@62 633 You can use the code in this hook as a starting point for some more
bos@62 634 exotic Bugzilla integration recipes. Here are a few possibilities:
bos@62 635 \begin{itemize}
bos@62 636 \item Require that every changeset pushed to the server have a valid
bos@62 637 bug~ID in its commit comment. In this case, you'd want to configure
bos@62 638 the hook as a \hook{pretxncommit} hook. This would allow the hook
bos@62 639 to reject changes that didn't contain bug IDs.
bos@62 640 \item Allow incoming changesets to automatically modify the
bos@62 641 \emph{state} of a bug, as well as simply adding a comment. For
bos@62 642 example, the hook could recognise the string ``fixed bug 31337'' as
bos@62 643 indicating that it should update the state of bug 31337 to
bos@62 644 ``requires testing''.
bos@62 645 \end{itemize}
bos@62 646
bos@62 647 \subsubsection{Configuring the \hook{bugzilla} hook}
bos@62 648 \label{sec:hook:bugzilla:config}
bos@62 649
bos@62 650 You should configure this hook in your server's \hgrc\ as an
bos@62 651 \hook{incoming} hook, for example as follows:
bos@62 652 \begin{codesample2}
bos@62 653 [hooks]
bos@62 654 incoming.bugzilla = python:hgext.bugzilla.hook
bos@62 655 \end{codesample2}
bos@62 656
bos@62 657 Because of the specialised nature of this hook, and because Bugzilla
bos@62 658 was not written with this kind of integration in mind, configuring
bos@62 659 this hook is a somewhat involved process.
bos@62 660
bos@62 661 Before you begin, you must install the MySQL bindings for Python on
bos@62 662 the host(s) where you'll be running the hook. If this is not
bos@62 663 available as a binary package for your system, you can download it
bos@62 664 from~\cite{web:mysql-python}.
bos@62 665
bos@62 666 Configuration information for this hook lives in the
bos@62 667 \rcsection{bugzilla} section of your \hgrc.
bos@62 668 \begin{itemize}
bos@64 669 \item[\rcitem{bugzilla}{version}] The version of Bugzilla installed on
bos@64 670 the server. The database schema that Bugzilla uses changes
bos@62 671 occasionally, so this hook has to know exactly which schema to use.
bos@62 672 At the moment, the only version supported is \texttt{2.16}.
bos@64 673 \item[\rcitem{bugzilla}{host}] The hostname of the MySQL server that
bos@64 674 stores your Bugzilla data. The database must be configured to allow
bos@64 675 connections from whatever host you are running the \hook{bugzilla}
bos@64 676 hook on.
bos@64 677 \item[\rcitem{bugzilla}{user}] The username with which to connect to
bos@64 678 the MySQL server. The database must be configured to allow this
bos@64 679 user to connect from whatever host you are running the
bos@64 680 \hook{bugzilla} hook on. This user must be able to access and
bos@64 681 modify Bugzilla tables. The default value of this item is
bos@64 682 \texttt{bugs}, which is the standard name of the Bugzilla user in a
bos@64 683 MySQL database.
bos@64 684 \item[\rcitem{bugzilla}{password}] The MySQL password for the user you
bos@62 685 configured above. This is stored as plain text, so you should make
bos@62 686 sure that unauthorised users cannot read the \hgrc\ file where you
bos@62 687 store this information.
bos@64 688 \item[\rcitem{bugzilla}{db}] The name of the Bugzilla database on the
bos@64 689 MySQL server. The default value of this item is \texttt{bugs},
bos@64 690 which is the standard name of the MySQL database where Bugzilla
bos@64 691 stores its data.
bos@64 692 \item[\rcitem{bugzilla}{notify}] If you want Bugzilla to send out a
bos@64 693 notification email to subscribers after this hook has added a
bos@64 694 comment to a bug, you will need this hook to run a command whenever
bos@64 695 it updates the database. The command to run depends on where you
bos@64 696 have installed Bugzilla, but it will typically look something like
bos@64 697 this, if you have Bugzilla installed in
bos@64 698 \dirname{/var/www/html/bugzilla}:
bos@62 699 \begin{codesample4}
bos@62 700 cd /var/www/html/bugzilla && ./processmail %s nobody@nowhere.com
bos@62 701 \end{codesample4}
bos@62 702 The Bugzilla \texttt{processmail} program expects to be given a
bos@62 703 bug~ID (the hook replaces ``\texttt{\%s}'' with the bug~ID) and an
bos@62 704 email address. It also expects to be able to write to some files in
bos@62 705 the directory that it runs in. If Bugzilla and this hook are not
bos@62 706 installed on the same machine, you will need to find a way to run
bos@62 707 \texttt{processmail} on the server where Bugzilla is installed.
bos@62 708 \end{itemize}
bos@62 709
bos@62 710 \subsubsection{Mapping committer names to Bugzilla user names}
bos@62 711
bos@62 712 By default, the \hgext{bugzilla} hook tries to use the email address
bos@62 713 of a changeset's committer as the Bugzilla user name with which to
bos@62 714 update a bug. If this does not suit your needs, you can map committer
bos@62 715 email addresses to Bugzilla user names using a \rcsection{usermap}
bos@62 716 section.
bos@62 717
bos@62 718 Each item in the \rcsection{usermap} section contains an email address
bos@62 719 on the left, and a Bugzilla user name on the right.
bos@62 720 \begin{codesample2}
bos@62 721 [usermap]
bos@62 722 jane.user@example.com = jane
bos@62 723 \end{codesample2}
bos@62 724 You can either keep the \rcsection{usermap} data in a normal \hgrc, or
bos@62 725 tell the \hgext{bugzilla} hook to read the information from an
bos@62 726 external \filename{usermap} file. In the latter case, you can store
bos@62 727 \filename{usermap} data by itself in (for example) a user-modifiable
bos@62 728 repository. This makes it possible to let your users maintain their
bos@64 729 own \rcitem{bugzilla}{usermap} entries. The main \hgrc\ file might
bos@64 730 look like this:
bos@62 731 \begin{codesample2}
bos@62 732 # regular hgrc file refers to external usermap file
bos@62 733 [bugzilla]
bos@62 734 usermap = /home/hg/repos/userdata/bugzilla-usermap.conf
bos@62 735 \end{codesample2}
bos@62 736 While the \filename{usermap} file that it refers to might look like
bos@62 737 this:
bos@62 738 \begin{codesample2}
bos@62 739 # bugzilla-usermap.conf - inside a hg repository
bos@62 740 [usermap]
bos@62 741 stephanie@example.com = steph
bos@62 742 \end{codesample2}
bos@62 743
bos@62 744 \subsubsection{Configuring the text that gets added to a bug}
bos@62 745
bos@62 746 You can configure the text that this hook adds as a comment; you
bos@62 747 specify it in the form of a Mercurial template. Several \hgrc\
bos@62 748 entries (still in the \rcsection{bugzilla} section) control this
bos@62 749 behaviour.
bos@62 750 \begin{itemize}
bos@62 751 \item[\texttt{strip}] The number of leading path elements to strip
bos@62 752 from a repository's path name to construct a partial path for a URL.
bos@62 753 For example, if the repositories on your server live under
bos@62 754 \dirname{/home/hg/repos}, and you have a repository whose path is
bos@62 755 \dirname{/home/hg/repos/app/tests}, then setting \texttt{strip} to
bos@62 756 \texttt{4} will give a partial path of \dirname{app/tests}. The
bos@62 757 hook will make this partial path available when expanding a
bos@62 758 template, as \texttt{webroot}.
bos@62 759 \item[\texttt{template}] The text of the template to use. In addition
bos@62 760 to the usual changeset-related variables, this template can use
bos@62 761 \texttt{hgweb} (the value of the \texttt{hgweb} configuration item
bos@62 762 above) and \texttt{webroot} (the path constructed using
bos@62 763 \texttt{strip} above).
bos@62 764 \end{itemize}
bos@62 765
bos@64 766 In addition, you can add a \rcitem{web}{baseurl} item to the
bos@64 767 \rcsection{web} section of your \hgrc. The \hgext{bugzilla} hook will
bos@64 768 make this available when expanding a template, as the base string to
bos@64 769 use when constructing a URL that will let users browse from a Bugzilla
bos@64 770 comment to view a changeset. Example:
bos@64 771 \begin{codesample2}
bos@64 772 [web]
bos@64 773 baseurl = http://hg.domain.com/
bos@64 774 \end{codesample2}
bos@64 775
bos@62 776 Here is an example set of \hgext{bugzilla} hook config information.
bos@62 777 \begin{codesample2}
bos@62 778 [bugzilla]
bos@62 779 host = bugzilla.example.com
bos@62 780 password = mypassword
bos@62 781 version = 2.16
bos@62 782 # server-side repos live in /home/hg/repos, so strip 4 leading
bos@62 783 # separators
bos@62 784 strip = 4
bos@62 785 hgweb = http://hg.example.com/
bos@62 786 usermap = /home/hg/repos/notify/bugzilla.conf
bos@62 787 template = Changeset \{node|short\}, made by \{author\} in the \{webroot\}
bos@62 788 repo, refers to this bug.\\nFor complete details, see
bos@62 789 \{hgweb\}\{webroot\}?cmd=changeset;node=\{node|short\}\\nChangeset
bos@62 790 description:\\n\\t\{desc|tabindent\}
bos@62 791 \end{codesample2}
bos@62 792
bos@62 793 \subsubsection{Testing and troubleshooting}
bos@62 794
bos@62 795 The most common problems with configuring the \hgext{bugzilla} hook
bos@62 796 relate to running Bugzilla's \filename{processmail} script and mapping
bos@62 797 committer names to user names.
bos@62 798
bos@62 799 Recall from section~\ref{sec:hook:bugzilla:config} above that the user
bos@62 800 that runs the Mercurial process on the server is also the one that
bos@62 801 will run the \filename{processmail} script. The
bos@62 802 \filename{processmail} script sometimes causes Bugzilla to write to
bos@62 803 files in its configuration directory, and Bugzilla's configuration
bos@62 804 files are usually owned by the user that your web server runs under.
bos@62 805
bos@62 806 You can cause \filename{processmail} to be run with the suitable
bos@62 807 user's identity using the \command{sudo} command. Here is an example
bos@62 808 entry for a \filename{sudoers} file.
bos@62 809 \begin{codesample2}
bos@62 810 hg_user = (httpd_user) NOPASSWD: /var/www/html/bugzilla/processmail-wrapper %s
bos@62 811 \end{codesample2}
bos@62 812 This allows the \texttt{hg\_user} user to run a
bos@62 813 \filename{processmail-wrapper} program under the identity of
bos@62 814 \texttt{httpd\_user}.
bos@62 815
bos@62 816 This indirection through a wrapper script is necessary, because
bos@62 817 \filename{processmail} expects to be run with its current directory
bos@62 818 set to wherever you installed Bugzilla; you can't specify that kind of
bos@62 819 constraint in a \filename{sudoers} file. The contents of the wrapper
bos@62 820 script are simple:
bos@62 821 \begin{codesample2}
bos@62 822 #!/bin/sh
bos@62 823 cd `dirname $0` && ./processmail "$1" nobody@example.com
bos@62 824 \end{codesample2}
bos@62 825 It doesn't seem to matter what email address you pass to
bos@62 826 \filename{processmail}.
bos@62 827
bos@62 828 If your \rcsection{usermap} is not set up correctly, users will see an
bos@62 829 error message from the \hgext{bugzilla} hook when they push changes
bos@62 830 to the server. The error message will look like this:
bos@62 831 \begin{codesample2}
bos@62 832 cannot find bugzilla user id for john.q.public@example.com
bos@62 833 \end{codesample2}
bos@62 834 What this means is that the committer's address,
bos@62 835 \texttt{john.q.public@example.com}, is not a valid Bugzilla user name,
bos@62 836 nor does it have an entry in your \rcsection{usermap} that maps it to
bos@62 837 a valid Bugzilla user name.
bos@62 838
bos@62 839 \subsection{\hgext{notify}---send email notifications}
bos@62 840
bos@62 841 Although Mercurial's built-in web server provides RSS feeds of changes
bos@62 842 in every repository, many people prefer to receive change
bos@62 843 notifications via email. The \hgext{notify} hook lets you send out
bos@62 844 notifications to a set of email addresses whenever changesets arrive
bos@62 845 that those subscribers are interested in.
bos@62 846
bos@62 847 As with the \hgext{bugzilla} hook, the \hgext{notify} hook is
bos@62 848 template-driven, so you can customise the contents of the notification
bos@62 849 messages that it sends.
bos@62 850
bos@62 851 By default, the \hgext{notify} hook includes a diff of every changeset
bos@63 852 that it sends out; you can limit the size of the diff, or turn this
bos@62 853 feature off entirely. It is useful for letting subscribers review
bos@62 854 changes immediately, rather than clicking to follow a URL.
bos@62 855
bos@62 856 \subsubsection{Configuring the \hgext{notify} hook}
bos@62 857
bos@62 858 You can set up the \hgext{notify} hook to send one email message per
bos@62 859 incoming changeset, or one per incoming group of changesets (all those
bos@62 860 that arrived in a single pull or push).
bos@62 861 \begin{codesample2}
bos@62 862 [hooks]
bos@62 863 # send one email per group of changes
bos@62 864 changegroup.notify = python:hgext.notify.hook
bos@62 865 # send one email per change
bos@62 866 incoming.notify = python:hgext.notify.hook
bos@62 867 \end{codesample2}
bos@62 868
bos@62 869 Configuration information for this hook lives in the
bos@62 870 \rcsection{notify} section of a \hgrc\ file.
bos@62 871 \begin{itemize}
bos@62 872 \item[\rcitem{notify}{test}] By default, this hook does not send out
bos@62 873 email at all; instead, it prints the message that it \emph{would}
bos@62 874 send. Set this item to \texttt{false} to allow email to be sent.
bos@62 875 The reason that sending of email is turned off by default is that it
bos@62 876 takes several tries to configure this extension exactly as you would
bos@62 877 like, and it would be bad form to spam subscribers with a number of
bos@62 878 ``broken'' notifications while you debug your configuration.
bos@62 879 \item[\rcitem{notify}{config}] The path to a configuration file that
bos@63 880 contains subscription information. This is kept separate from the
bos@62 881 main \hgrc\ so that you can maintain it in a repository of its own.
bos@62 882 People can then clone that repository, update their subscriptions,
bos@62 883 and push the changes back to your server.
bos@62 884 \item[\rcitem{notify}{strip}] The number of leading path separator
bos@62 885 characters to strip from a repository's path, when deciding whether
bos@62 886 a repository has subscribers. For example, if the repositories on
bos@62 887 your server live in \dirname{/home/hg/repos}, and \hgext{notify} is
bos@62 888 considering a repository named \dirname{/home/hg/repos/shared/test},
bos@62 889 setting \rcitem{notify}{strip} to \texttt{4} will cause
bos@62 890 \hgext{notify} to trim the path it considers down to
bos@62 891 \dirname{shared/test}, and it will match subscribers against that.
bos@62 892 \item[\rcitem{notify}{template}] The template text to use when sending
bos@62 893 messages. This specifies both the contents of the message header
bos@62 894 and its body.
bos@62 895 \item[\rcitem{notify}{maxdiff}] The maximum number of lines of diff
bos@62 896 data to append to the end of a message. If a diff is longer than
bos@62 897 this, it is truncated. By default, this is set to 300. Set this to
bos@62 898 \texttt{0} to omit diffs from notification emails.
bos@62 899 \item[\rcitem{notify}{sources}] A list of sources of changesets to
bos@62 900 consider. This lets you limit \hgext{notify} to only sending out
bos@62 901 email about changes that remote users pushed into this repository
bos@62 902 via a server, for example. See section~\ref{sec:hook:sources} for
bos@62 903 the sources you can specify here.
bos@62 904 \end{itemize}
bos@62 905
bos@62 906 If you set the \rcitem{web}{baseurl} item in the \rcsection{web}
bos@62 907 section, you can use it in a template; it will be available as
bos@62 908 \texttt{webroot}.
bos@62 909
bos@62 910 Here is an example set of \hgext{notify} configuration information.
bos@62 911 \begin{codesample2}
bos@62 912 [notify]
bos@62 913 # really send email
bos@62 914 test = false
bos@62 915 # subscriber data lives in the notify repo
bos@62 916 config = /home/hg/repos/notify/notify.conf
bos@62 917 # repos live in /home/hg/repos on server, so strip 4 "/" chars
bos@62 918 strip = 4
timonator@285 919 template = X-Hg-Repo: \{webroot\}
timonator@285 920 Subject: \{webroot\}: \{desc|firstline|strip\}
timonator@285 921 From: \{author\}
timonator@285 922
timonator@285 923 changeset \{node|short\} in \{root\}
timonator@285 924 details: \{baseurl\}\{webroot\}?cmd=changeset;node=\{node|short\}
timonator@285 925 description:
timonator@285 926 \{desc|tabindent|strip\}
bos@62 927
bos@62 928 [web]
bos@62 929 baseurl = http://hg.example.com/
bos@62 930 \end{codesample2}
bos@62 931
bos@62 932 This will produce a message that looks like the following:
bos@62 933 \begin{codesample2}
bos@62 934 X-Hg-Repo: tests/slave
bos@62 935 Subject: tests/slave: Handle error case when slave has no buffers
bos@62 936 Date: Wed, 2 Aug 2006 15:25:46 -0700 (PDT)
bos@62 937
bos@62 938 changeset 3cba9bfe74b5 in /home/hg/repos/tests/slave
bos@62 939 details: http://hg.example.com/tests/slave?cmd=changeset;node=3cba9bfe74b5
bos@62 940 description:
bos@62 941 Handle error case when slave has no buffers
bos@62 942 diffs (54 lines):
bos@62 943
bos@62 944 diff -r 9d95df7cf2ad -r 3cba9bfe74b5 include/tests.h
bos@62 945 --- a/include/tests.h Wed Aug 02 15:19:52 2006 -0700
bos@62 946 +++ b/include/tests.h Wed Aug 02 15:25:26 2006 -0700
bos@62 947 @@ -212,6 +212,15 @@ static __inline__ void test_headers(void *h)
bos@62 948 [...snip...]
bos@62 949 \end{codesample2}
bos@62 950
bos@62 951 \subsubsection{Testing and troubleshooting}
bos@62 952
bos@62 953 Do not forget that by default, the \hgext{notify} extension \emph{will
bos@62 954 not send any mail} until you explicitly configure it to do so, by
bos@62 955 setting \rcitem{notify}{test} to \texttt{false}. Until you do that,
bos@62 956 it simply prints the message it \emph{would} send.
bos@44 957
bos@64 958 \section{Information for writers of hooks}
bos@41 959 \label{sec:hook:ref}
bos@39 960
bos@39 961 \subsection{In-process hook execution}
bos@39 962
bos@39 963 An in-process hook is called with arguments of the following form:
bos@39 964 \begin{codesample2}
bos@39 965 def myhook(ui, repo, **kwargs):
bos@39 966 pass
bos@39 967 \end{codesample2}
bos@39 968 The \texttt{ui} parameter is a \pymodclass{mercurial.ui}{ui} object.
bos@39 969 The \texttt{repo} parameter is a
bos@39 970 \pymodclass{mercurial.localrepo}{localrepository} object. The
bos@39 971 names and values of the \texttt{**kwargs} parameters depend on the
bos@39 972 hook being invoked, with the following common features:
bos@39 973 \begin{itemize}
bos@39 974 \item If a parameter is named \texttt{node} or
bos@39 975 \texttt{parent\emph{N}}, it will contain a hexadecimal changeset ID.
bos@39 976 The empty string is used to represent ``null changeset ID'' instead
bos@39 977 of a string of zeroes.
bos@62 978 \item If a parameter is named \texttt{url}, it will contain the URL of
bos@62 979 a remote repository, if that can be determined.
bos@39 980 \item Boolean-valued parameters are represented as Python
bos@39 981 \texttt{bool} objects.
bos@39 982 \end{itemize}
bos@39 983
bos@39 984 An in-process hook is called without a change to the process's working
bos@39 985 directory (unlike external hooks, which are run in the root of the
bos@62 986 repository). It must not change the process's working directory, or
bos@62 987 it will cause any calls it makes into the Mercurial API to fail.
bos@62 988
bos@62 989 If a hook returns a boolean ``false'' value, it is considered to have
bos@62 990 succeeded. If it returns a boolean ``true'' value or raises an
bos@62 991 exception, it is considered to have failed. A useful way to think of
bos@62 992 the calling convention is ``tell me if you fail''.
bos@62 993
bos@62 994 Note that changeset IDs are passed into Python hooks as hexadecimal
bos@62 995 strings, not the binary hashes that Mercurial's APIs normally use. To
bos@62 996 convert a hash from hex to binary, use the
bos@62 997 \pymodfunc{mercurial.node}{bin} function.
bos@39 998
bos@39 999 \subsection{External hook execution}
bos@39 1000
bos@62 1001 An external hook is passed to the shell of the user running Mercurial.
bos@62 1002 Features of that shell, such as variable substitution and command
bos@39 1003 redirection, are available. The hook is run in the root directory of
bos@62 1004 the repository (unlike in-process hooks, which are run in the same
bos@62 1005 directory that Mercurial was run in).
bos@39 1006
bos@39 1007 Hook parameters are passed to the hook as environment variables. Each
bos@39 1008 environment variable's name is converted in upper case and prefixed
bos@39 1009 with the string ``\texttt{HG\_}''. For example, if the name of a
bos@39 1010 parameter is ``\texttt{node}'', the name of the environment variable
bos@39 1011 representing that parameter will be ``\texttt{HG\_NODE}''.
bos@39 1012
bos@39 1013 A boolean parameter is represented as the string ``\texttt{1}'' for
bos@39 1014 ``true'', ``\texttt{0}'' for ``false''. If an environment variable is
bos@39 1015 named \envar{HG\_NODE}, \envar{HG\_PARENT1} or \envar{HG\_PARENT2}, it
bos@39 1016 contains a changeset ID represented as a hexadecimal string. The
bos@39 1017 empty string is used to represent ``null changeset ID'' instead of a
bos@62 1018 string of zeroes. If an environment variable is named
bos@62 1019 \envar{HG\_URL}, it will contain the URL of a remote repository, if
bos@62 1020 that can be determined.
bos@39 1021
bos@39 1022 If a hook exits with a status of zero, it is considered to have
bos@39 1023 succeeded. If it exits with a non-zero status, it is considered to
bos@39 1024 have failed.
bos@39 1025
bos@62 1026 \subsection{Finding out where changesets come from}
bos@62 1027
bos@62 1028 A hook that involves the transfer of changesets between a local
bos@62 1029 repository and another may be able to find out information about the
bos@62 1030 ``far side''. Mercurial knows \emph{how} changes are being
bos@62 1031 transferred, and in many cases \emph{where} they are being transferred
bos@62 1032 to or from.
bos@62 1033
bos@62 1034 \subsubsection{Sources of changesets}
bos@62 1035 \label{sec:hook:sources}
bos@62 1036
bos@62 1037 Mercurial will tell a hook what means are, or were, used to transfer
bos@62 1038 changesets between repositories. This is provided by Mercurial in a
bos@62 1039 Python parameter named \texttt{source}, or an environment variable named
bos@62 1040 \envar{HG\_SOURCE}.
bos@62 1041
bos@62 1042 \begin{itemize}
bos@62 1043 \item[\texttt{serve}] Changesets are transferred to or from a remote
bos@62 1044 repository over http or ssh.
bos@62 1045 \item[\texttt{pull}] Changesets are being transferred via a pull from
bos@62 1046 one repository into another.
bos@62 1047 \item[\texttt{push}] Changesets are being transferred via a push from
bos@62 1048 one repository into another.
bos@62 1049 \item[\texttt{bundle}] Changesets are being transferred to or from a
bos@62 1050 bundle.
bos@62 1051 \end{itemize}
bos@62 1052
bos@62 1053 \subsubsection{Where changes are going---remote repository URLs}
bos@62 1054 \label{sec:hook:url}
bos@62 1055
bos@62 1056 When possible, Mercurial will tell a hook the location of the ``far
bos@62 1057 side'' of an activity that transfers changeset data between
bos@62 1058 repositories. This is provided by Mercurial in a Python parameter
bos@62 1059 named \texttt{url}, or an environment variable named \envar{HG\_URL}.
bos@62 1060
bos@62 1061 This information is not always known. If a hook is invoked in a
bos@62 1062 repository that is being served via http or ssh, Mercurial cannot tell
bos@62 1063 where the remote repository is, but it may know where the client is
bos@62 1064 connecting from. In such cases, the URL will take one of the
bos@62 1065 following forms:
bos@62 1066 \begin{itemize}
bos@62 1067 \item \texttt{remote:ssh:\emph{ip-address}}---remote ssh client, at
bos@62 1068 the given IP address.
bos@62 1069 \item \texttt{remote:http:\emph{ip-address}}---remote http client, at
bos@62 1070 the given IP address. If the client is using SSL, this will be of
bos@62 1071 the form \texttt{remote:https:\emph{ip-address}}.
bos@62 1072 \item Empty---no information could be discovered about the remote
bos@62 1073 client.
bos@62 1074 \end{itemize}
bos@62 1075
bos@64 1076 \section{Hook reference}
bos@64 1077
bos@64 1078 \subsection{\hook{changegroup}---after remote changesets added}
bos@39 1079 \label{sec:hook:changegroup}
bos@39 1080
bos@40 1081 This hook is run after a group of pre-existing changesets has been
bos@40 1082 added to the repository, for example via a \hgcmd{pull} or
bos@40 1083 \hgcmd{unbundle}. This hook is run once per operation that added one
bos@41 1084 or more changesets. This is in contrast to the \hook{incoming} hook,
bos@41 1085 which is run once per changeset, regardless of whether the changesets
bos@41 1086 arrive in a group.
bos@41 1087
bos@41 1088 Some possible uses for this hook include kicking off an automated
bos@41 1089 build or test of the added changesets, updating a bug database, or
bos@41 1090 notifying subscribers that a repository contains new changes.
bos@40 1091
bos@40 1092 Parameters to this hook:
bos@40 1093 \begin{itemize}
bos@40 1094 \item[\texttt{node}] A changeset ID. The changeset ID of the first
bos@40 1095 changeset in the group that was added. All changesets between this
bos@40 1096 and \index{tags!\texttt{tip}}\texttt{tip}, inclusive, were added by
bos@40 1097 a single \hgcmd{pull}, \hgcmd{push} or \hgcmd{unbundle}.
bos@62 1098 \item[\texttt{source}] A string. The source of these changes. See
bos@62 1099 section~\ref{sec:hook:sources} for details.
bos@62 1100 \item[\texttt{url}] A URL. The location of the remote repository, if
bos@62 1101 known. See section~\ref{sec:hook:url} for more information.
bos@40 1102 \end{itemize}
bos@40 1103
bos@40 1104 See also: \hook{incoming} (section~\ref{sec:hook:incoming}),
bos@40 1105 \hook{prechangegroup} (section~\ref{sec:hook:prechangegroup}),
bos@40 1106 \hook{pretxnchangegroup} (section~\ref{sec:hook:pretxnchangegroup})
bos@39 1107
bos@64 1108 \subsection{\hook{commit}---after a new changeset is created}
bos@39 1109 \label{sec:hook:commit}
bos@39 1110
bos@40 1111 This hook is run after a new changeset has been created.
bos@40 1112
bos@40 1113 Parameters to this hook:
bos@40 1114 \begin{itemize}
bos@40 1115 \item[\texttt{node}] A changeset ID. The changeset ID of the newly
bos@40 1116 committed changeset.
bos@40 1117 \item[\texttt{parent1}] A changeset ID. The changeset ID of the first
bos@40 1118 parent of the newly committed changeset.
bos@40 1119 \item[\texttt{parent2}] A changeset ID. The changeset ID of the second
bos@40 1120 parent of the newly committed changeset.
bos@40 1121 \end{itemize}
bos@40 1122
bos@40 1123 See also: \hook{precommit} (section~\ref{sec:hook:precommit}),
bos@40 1124 \hook{pretxncommit} (section~\ref{sec:hook:pretxncommit})
bos@40 1125
bos@64 1126 \subsection{\hook{incoming}---after one remote changeset is added}
bos@40 1127 \label{sec:hook:incoming}
bos@40 1128
bos@40 1129 This hook is run after a pre-existing changeset has been added to the
bos@40 1130 repository, for example via a \hgcmd{push}. If a group of changesets
bos@40 1131 was added in a single operation, this hook is called once for each
bos@40 1132 added changeset.
bos@40 1133
bos@41 1134 You can use this hook for the same purposes as the \hook{changegroup}
bos@41 1135 hook (section~\ref{sec:hook:changegroup}); it's simply more convenient
bos@54 1136 sometimes to run a hook once per group of changesets, while other
bos@41 1137 times it's handier once per changeset.
bos@41 1138
bos@40 1139 Parameters to this hook:
bos@40 1140 \begin{itemize}
bos@40 1141 \item[\texttt{node}] A changeset ID. The ID of the newly added
bos@39 1142 changeset.
bos@62 1143 \item[\texttt{source}] A string. The source of these changes. See
bos@62 1144 section~\ref{sec:hook:sources} for details.
bos@62 1145 \item[\texttt{url}] A URL. The location of the remote repository, if
bos@62 1146 known. See section~\ref{sec:hook:url} for more information.
bos@40 1147 \end{itemize}
bos@40 1148
bos@40 1149 See also: \hook{changegroup} (section~\ref{sec:hook:changegroup}) \hook{prechangegroup} (section~\ref{sec:hook:prechangegroup}), \hook{pretxnchangegroup} (section~\ref{sec:hook:pretxnchangegroup})
bos@40 1150
bos@64 1151 \subsection{\hook{outgoing}---after changesets are propagated}
bos@40 1152 \label{sec:hook:outgoing}
bos@40 1153
bos@40 1154 This hook is run after a group of changesets has been propagated out
bos@40 1155 of this repository, for example by a \hgcmd{push} or \hgcmd{bundle}
bos@40 1156 command.
bos@40 1157
bos@41 1158 One possible use for this hook is to notify administrators that
bos@41 1159 changes have been pulled.
bos@41 1160
bos@40 1161 Parameters to this hook:
bos@40 1162 \begin{itemize}
bos@40 1163 \item[\texttt{node}] A changeset ID. The changeset ID of the first
bos@40 1164 changeset of the group that was sent.
bos@62 1165 \item[\texttt{source}] A string. The source of the of the operation
bos@62 1166 (see section~\ref{sec:hook:sources}). If a remote client pulled
bos@62 1167 changes from this repository, \texttt{source} will be
bos@62 1168 \texttt{serve}. If the client that obtained changes from this
bos@62 1169 repository was local, \texttt{source} will be \texttt{bundle},
bos@62 1170 \texttt{pull}, or \texttt{push}, depending on the operation the
bos@62 1171 client performed.
bos@62 1172 \item[\texttt{url}] A URL. The location of the remote repository, if
bos@62 1173 known. See section~\ref{sec:hook:url} for more information.
bos@40 1174 \end{itemize}
bos@40 1175
bos@40 1176 See also: \hook{preoutgoing} (section~\ref{sec:hook:preoutgoing})
bos@40 1177
bos@64 1178 \subsection{\hook{prechangegroup}---before starting to add remote changesets}
bos@40 1179 \label{sec:hook:prechangegroup}
bos@40 1180
bos@41 1181 This controlling hook is run before Mercurial begins to add a group of
bos@41 1182 changesets from another repository.
bos@41 1183
bos@41 1184 This hook does not have any information about the changesets to be
bos@41 1185 added, because it is run before transmission of those changesets is
bos@41 1186 allowed to begin. If this hook fails, the changesets will not be
bos@41 1187 transmitted.
bos@41 1188
bos@41 1189 One use for this hook is to prevent external changes from being added
bos@62 1190 to a repository. For example, you could use this to ``freeze'' a
bos@62 1191 server-hosted branch temporarily or permanently so that users cannot
bos@62 1192 push to it, while still allowing a local administrator to modify the
bos@62 1193 repository.
bos@62 1194
bos@62 1195 Parameters to this hook:
bos@62 1196 \begin{itemize}
bos@62 1197 \item[\texttt{source}] A string. The source of these changes. See
bos@62 1198 section~\ref{sec:hook:sources} for details.
bos@62 1199 \item[\texttt{url}] A URL. The location of the remote repository, if
bos@62 1200 known. See section~\ref{sec:hook:url} for more information.
bos@62 1201 \end{itemize}
bos@40 1202
bos@40 1203 See also: \hook{changegroup} (section~\ref{sec:hook:changegroup}),
bos@40 1204 \hook{incoming} (section~\ref{sec:hook:incoming}), ,
bos@40 1205 \hook{pretxnchangegroup} (section~\ref{sec:hook:pretxnchangegroup})
bos@40 1206
bos@64 1207 \subsection{\hook{precommit}---before starting to commit a changeset}
bos@40 1208 \label{sec:hook:precommit}
bos@40 1209
bos@41 1210 This hook is run before Mercurial begins to commit a new changeset.
bos@41 1211 It is run before Mercurial has any of the metadata for the commit,
bos@41 1212 such as the files to be committed, the commit message, or the commit
bos@41 1213 date.
bos@41 1214
bos@41 1215 One use for this hook is to disable the ability to commit new
bos@41 1216 changesets, while still allowing incoming changesets. Another is to
bos@41 1217 run a build or test, and only allow the commit to begin if the build
bos@41 1218 or test succeeds.
bos@40 1219
bos@40 1220 Parameters to this hook:
bos@40 1221 \begin{itemize}
bos@40 1222 \item[\texttt{parent1}] A changeset ID. The changeset ID of the first
bos@40 1223 parent of the working directory.
bos@40 1224 \item[\texttt{parent2}] A changeset ID. The changeset ID of the second
bos@40 1225 parent of the working directory.
bos@40 1226 \end{itemize}
bos@40 1227 If the commit proceeds, the parents of the working directory will
bos@40 1228 become the parents of the new changeset.
bos@40 1229
bos@40 1230 See also: \hook{commit} (section~\ref{sec:hook:commit}),
bos@40 1231 \hook{pretxncommit} (section~\ref{sec:hook:pretxncommit})
bos@40 1232
bos@64 1233 \subsection{\hook{preoutgoing}---before starting to propagate changesets}
bos@40 1234 \label{sec:hook:preoutgoing}
bos@40 1235
bos@40 1236 This hook is invoked before Mercurial knows the identities of the
bos@40 1237 changesets to be transmitted.
bos@40 1238
bos@41 1239 One use for this hook is to prevent changes from being transmitted to
bos@41 1240 another repository.
bos@41 1241
bos@40 1242 Parameters to this hook:
bos@40 1243 \begin{itemize}
bos@40 1244 \item[\texttt{source}] A string. The source of the operation that is
bos@62 1245 attempting to obtain changes from this repository (see
bos@62 1246 section~\ref{sec:hook:sources}). See the documentation for the
bos@62 1247 \texttt{source} parameter to the \hook{outgoing} hook, in
bos@62 1248 section~\ref{sec:hook:outgoing}, for possible values of this
bos@62 1249 parameter.
bos@62 1250 \item[\texttt{url}] A URL. The location of the remote repository, if
bos@62 1251 known. See section~\ref{sec:hook:url} for more information.
bos@40 1252 \end{itemize}
bos@40 1253
bos@40 1254 See also: \hook{outgoing} (section~\ref{sec:hook:outgoing})
bos@40 1255
bos@64 1256 \subsection{\hook{pretag}---before tagging a changeset}
bos@40 1257 \label{sec:hook:pretag}
bos@40 1258
bos@41 1259 This controlling hook is run before a tag is created. If the hook
bos@41 1260 succeeds, creation of the tag proceeds. If the hook fails, the tag is
bos@41 1261 not created.
bos@41 1262
bos@40 1263 Parameters to this hook:
bos@40 1264 \begin{itemize}
bos@40 1265 \item[\texttt{local}] A boolean. Whether the tag is local to this
bos@244 1266 repository instance (i.e.~stored in \sfilename{.hg/localtags}) or
bos@244 1267 managed by Mercurial (stored in \sfilename{.hgtags}).
bos@40 1268 \item[\texttt{node}] A changeset ID. The ID of the changeset to be tagged.
bos@40 1269 \item[\texttt{tag}] A string. The name of the tag to be created.
bos@40 1270 \end{itemize}
bos@40 1271
bos@40 1272 If the tag to be created is revision-controlled, the \hook{precommit}
bos@40 1273 and \hook{pretxncommit} hooks (sections~\ref{sec:hook:commit}
bos@40 1274 and~\ref{sec:hook:pretxncommit}) will also be run.
bos@40 1275
bos@40 1276 See also: \hook{tag} (section~\ref{sec:hook:tag})
bos@40 1277
bos@64 1278 \subsection{\hook{pretxnchangegroup}---before completing addition of
bos@64 1279 remote changesets}
bos@40 1280 \label{sec:hook:pretxnchangegroup}
bos@40 1281
bos@41 1282 This controlling hook is run before a transaction---that manages the
bos@41 1283 addition of a group of new changesets from outside the
bos@41 1284 repository---completes. If the hook succeeds, the transaction
bos@41 1285 completes, and all of the changesets become permanent within this
bos@41 1286 repository. If the hook fails, the transaction is rolled back, and
bos@41 1287 the data for the changesets is erased.
bos@41 1288
bos@41 1289 This hook can access the metadata associated with the almost-added
bos@41 1290 changesets, but it should not do anything permanent with this data.
bos@41 1291 It must also not modify the working directory.
bos@41 1292
bos@41 1293 While this hook is running, if other Mercurial processes access this
bos@41 1294 repository, they will be able to see the almost-added changesets as if
bos@41 1295 they are permanent. This may lead to race conditions if you do not
bos@41 1296 take steps to avoid them.
bos@41 1297
bos@41 1298 This hook can be used to automatically vet a group of changesets. If
bos@41 1299 the hook fails, all of the changesets are ``rejected'' when the
bos@41 1300 transaction rolls back.
bos@41 1301
bos@62 1302 Parameters to this hook:
bos@62 1303 \begin{itemize}
bos@62 1304 \item[\texttt{node}] A changeset ID. The changeset ID of the first
bos@62 1305 changeset in the group that was added. All changesets between this
bos@62 1306 and \index{tags!\texttt{tip}}\texttt{tip}, inclusive, were added by
bos@62 1307 a single \hgcmd{pull}, \hgcmd{push} or \hgcmd{unbundle}.
bos@62 1308 \item[\texttt{source}] A string. The source of these changes. See
bos@62 1309 section~\ref{sec:hook:sources} for details.
bos@62 1310 \item[\texttt{url}] A URL. The location of the remote repository, if
bos@62 1311 known. See section~\ref{sec:hook:url} for more information.
bos@62 1312 \end{itemize}
bos@40 1313
bos@40 1314 See also: \hook{changegroup} (section~\ref{sec:hook:changegroup}),
bos@40 1315 \hook{incoming} (section~\ref{sec:hook:incoming}),
bos@40 1316 \hook{prechangegroup} (section~\ref{sec:hook:prechangegroup})
bos@40 1317
bos@64 1318 \subsection{\hook{pretxncommit}---before completing commit of new changeset}
bos@40 1319 \label{sec:hook:pretxncommit}
bos@40 1320
bos@41 1321 This controlling hook is run before a transaction---that manages a new
bos@41 1322 commit---completes. If the hook succeeds, the transaction completes
bos@41 1323 and the changeset becomes permanent within this repository. If the
bos@41 1324 hook fails, the transaction is rolled back, and the commit data is
bos@41 1325 erased.
bos@41 1326
bos@41 1327 This hook can access the metadata associated with the almost-new
bos@41 1328 changeset, but it should not do anything permanent with this data. It
bos@41 1329 must also not modify the working directory.
bos@41 1330
bos@41 1331 While this hook is running, if other Mercurial processes access this
bos@41 1332 repository, they will be able to see the almost-new changeset as if it
bos@41 1333 is permanent. This may lead to race conditions if you do not take
bos@41 1334 steps to avoid them.
bos@41 1335
bos@62 1336 Parameters to this hook:
bos@62 1337 \begin{itemize}
bos@62 1338 \item[\texttt{node}] A changeset ID. The changeset ID of the newly
bos@62 1339 committed changeset.
bos@62 1340 \item[\texttt{parent1}] A changeset ID. The changeset ID of the first
bos@62 1341 parent of the newly committed changeset.
bos@62 1342 \item[\texttt{parent2}] A changeset ID. The changeset ID of the second
bos@62 1343 parent of the newly committed changeset.
bos@62 1344 \end{itemize}
bos@40 1345
bos@40 1346 See also: \hook{precommit} (section~\ref{sec:hook:precommit})
bos@40 1347
bos@64 1348 \subsection{\hook{preupdate}---before updating or merging working directory}
bos@40 1349 \label{sec:hook:preupdate}
bos@40 1350
bos@41 1351 This controlling hook is run before an update or merge of the working
bos@41 1352 directory begins. It is run only if Mercurial's normal pre-update
bos@41 1353 checks determine that the update or merge can proceed. If the hook
bos@41 1354 succeeds, the update or merge may proceed; if it fails, the update or
bos@41 1355 merge does not start.
bos@41 1356
bos@40 1357 Parameters to this hook:
bos@40 1358 \begin{itemize}
bos@40 1359 \item[\texttt{parent1}] A changeset ID. The ID of the parent that the
bos@40 1360 working directory is to be updated to. If the working directory is
bos@40 1361 being merged, it will not change this parent.
bos@40 1362 \item[\texttt{parent2}] A changeset ID. Only set if the working
bos@40 1363 directory is being merged. The ID of the revision that the working
bos@40 1364 directory is being merged with.
bos@40 1365 \end{itemize}
bos@40 1366
bos@40 1367 See also: \hook{update} (section~\ref{sec:hook:update})
bos@40 1368
bos@64 1369 \subsection{\hook{tag}---after tagging a changeset}
bos@40 1370 \label{sec:hook:tag}
bos@40 1371
bos@41 1372 This hook is run after a tag has been created.
bos@41 1373
bos@62 1374 Parameters to this hook:
bos@62 1375 \begin{itemize}
bos@62 1376 \item[\texttt{local}] A boolean. Whether the new tag is local to this
bos@244 1377 repository instance (i.e.~stored in \sfilename{.hg/localtags}) or
bos@244 1378 managed by Mercurial (stored in \sfilename{.hgtags}).
bos@62 1379 \item[\texttt{node}] A changeset ID. The ID of the changeset that was
bos@62 1380 tagged.
bos@62 1381 \item[\texttt{tag}] A string. The name of the tag that was created.
bos@62 1382 \end{itemize}
bos@40 1383
bos@40 1384 If the created tag is revision-controlled, the \hook{commit} hook
bos@41 1385 (section~\ref{sec:hook:commit}) is run before this hook.
bos@40 1386
bos@40 1387 See also: \hook{pretag} (section~\ref{sec:hook:pretag})
bos@40 1388
bos@64 1389 \subsection{\hook{update}---after updating or merging working directory}
bos@40 1390 \label{sec:hook:update}
bos@40 1391
bos@41 1392 This hook is run after an update or merge of the working directory
bos@41 1393 completes. Since a merge can fail (if the external \command{hgmerge}
bos@41 1394 command fails to resolve conflicts in a file), this hook communicates
bos@41 1395 whether the update or merge completed cleanly.
bos@41 1396
bos@40 1397 \begin{itemize}
bos@40 1398 \item[\texttt{error}] A boolean. Indicates whether the update or
bos@40 1399 merge completed successfully.
bos@40 1400 \item[\texttt{parent1}] A changeset ID. The ID of the parent that the
bos@40 1401 working directory was updated to. If the working directory was
bos@40 1402 merged, it will not have changed this parent.
bos@40 1403 \item[\texttt{parent2}] A changeset ID. Only set if the working
bos@40 1404 directory was merged. The ID of the revision that the working
bos@40 1405 directory was merged with.
bos@40 1406 \end{itemize}
bos@40 1407
bos@40 1408 See also: \hook{preupdate} (section~\ref{sec:hook:preupdate})
bos@34 1409
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