post-receive-email example hook: detect rewind-only updates and output sensible message
[git/git.git] / contrib / hooks / post-receive-email
1 #!/bin/sh
2 #
3 # Copyright (c) 2007 Andy Parkins
4 #
5 # An example hook script to mail out commit update information. This hook sends emails
6 # listing new revisions to the repository introduced by the change being reported. The
7 # rule is that (for branch updates) each commit will appear on one email and one email
8 # only.
9 #
10 # This hook is stored in the contrib/hooks directory. Your distribution will have put
11 # this somewhere standard. You should make this script executable then link to it in
12 # the repository you would like to use it in. For example, on debian the hook is stored
13 # in /usr/share/doc/git-core/contrib/hooks/post-receive-email:
14 #
15 # chmod a+x post-receive-email
16 # cd /path/to/your/repository.git
17 # ln -sf /usr/share/doc/git-core/contrib/hooks/post-receive-email hooks/post-receive
18 #
19 # This hook script assumes it is enabled on the central repository of a project, with
20 # all users pushing only to it and not between each other. It will still work if you
21 # don't operate in that style, but it would become possible for the email to be from
22 # someone other than the person doing the push.
23 #
24 # Config
25 # ------
26 # hooks.mailinglist
27 # This is the list that all pushes will go to; leave it blank to not send
28 # emails for every ref update.
29 # hooks.announcelist
30 # This is the list that all pushes of annotated tags will go to. Leave it
31 # blank to default to the mailinglist field. The announce emails lists the
32 # short log summary of the changes since the last annotated tag.
33 # hook.envelopesender
34 # If set then the -f option is passed to sendmail to allow the envelope sender
35 # address to be set
36 #
37 # Notes
38 # -----
39 # All emails have their subjects prefixed with "[SCM]" to aid filtering.
40 # All emails include the headers "X-Git-Refname", "X-Git-Oldrev",
41 # "X-Git-Newrev", and "X-Git-Reftype" to enable fine tuned filtering and
42 # give information for debugging.
43 #
44
45 # ---------------------------- Functions
46
47 #
48 # Top level email generation function. This decides what type of update
49 # this is and calls the appropriate body-generation routine after outputting
50 # the common header
51 #
52 # Note this function doesn't actually generate any email output, that is taken
53 # care of by the functions it calls:
54 # - generate_email_header
55 # - generate_create_XXXX_email
56 # - generate_update_XXXX_email
57 # - generate_delete_XXXX_email
58 # - generate_email_footer
59 #
60 generate_email()
61 {
62 # --- Arguments
63 oldrev=$(git rev-parse $1)
64 newrev=$(git rev-parse $2)
65 refname="$3"
66
67 # --- Interpret
68 # 0000->1234 (create)
69 # 1234->2345 (update)
70 # 2345->0000 (delete)
71 if expr "$oldrev" : '0*$' >/dev/null
72 then
73 change_type="create"
74 else
75 if expr "$newrev" : '0*$' >/dev/null
76 then
77 change_type="delete"
78 else
79 change_type="update"
80 fi
81 fi
82
83 # --- Get the revision types
84 newrev_type=$(git cat-file -t $newrev 2> /dev/null)
85 oldrev_type=$(git cat-file -t "$oldrev" 2> /dev/null)
86 case "$change_type" in
87 create|update)
88 rev="$newrev"
89 rev_type="$newrev_type"
90 ;;
91 delete)
92 rev="$oldrev"
93 rev_type="$oldrev_type"
94 ;;
95 esac
96
97 # The revision type tells us what type the commit is, combined with
98 # the location of the ref we can decide between
99 # - working branch
100 # - tracking branch
101 # - unannoted tag
102 # - annotated tag
103 case "$refname","$rev_type" in
104 refs/tags/*,commit)
105 # un-annotated tag
106 refname_type="tag"
107 short_refname=${refname##refs/tags/}
108 ;;
109 refs/tags/*,tag)
110 # annotated tag
111 refname_type="annotated tag"
112 short_refname=${refname##refs/tags/}
113 # change recipients
114 if [ -n "$announcerecipients" ]; then
115 recipients="$announcerecipients"
116 fi
117 ;;
118 refs/heads/*,commit)
119 # branch
120 refname_type="branch"
121 short_refname=${refname##refs/heads/}
122 ;;
123 refs/remotes/*,commit)
124 # tracking branch
125 refname_type="tracking branch"
126 short_refname=${refname##refs/remotes/}
127 echo >&2 "*** Push-update of tracking branch, $refname"
128 echo >&2 "*** - no email generated."
129 exit 0
130 ;;
131 *)
132 # Anything else (is there anything else?)
133 echo >&2 "*** Unknown type of update to $refname ($rev_type)"
134 echo >&2 "*** - no email generated"
135 exit 1
136 ;;
137 esac
138
139 # Check if we've got anyone to send to
140 if [ -z "$recipients" ]; then
141 echo >&2 "*** hooks.recipients is not set so no email will be sent"
142 echo >&2 "*** for $refname update $oldrev->$newrev"
143 exit 0
144 fi
145
146 # Email parameters
147 # The committer will be obtained from the latest existing rev; so
148 # for a deletion it will be the oldrev, for the others, then newrev
149 committer=$(git show --pretty=full -s $rev | sed -ne "s/^Commit: //p" |
150 sed -ne 's/\(.*\) </"\1" </p')
151 # The email subject will contain the best description of the ref
152 # that we can build from the parameters
153 describe=$(git describe $rev 2>/dev/null)
154 if [ -z "$describe" ]; then
155 describe=$rev
156 fi
157
158 generate_email_header
159
160 # Call the correct body generation function
161 fn_name=general
162 case "$refname_type" in
163 "tracking branch"|branch)
164 fn_name=branch
165 ;;
166 "annotated tag")
167 fn_name=atag
168 ;;
169 esac
170 generate_${change_type}_${fn_name}_email
171
172 generate_email_footer
173 }
174
175 generate_email_header()
176 {
177 # --- Email (all stdout will be the email)
178 # Generate header
179 cat <<-EOF
180 From: $committer
181 To: $recipients
182 Subject: ${EMAILPREFIX}$projectdesc $refname_type, $short_refname, ${change_type}d. $describe
183 X-Git-Refname: $refname
184 X-Git-Reftype: $refname_type
185 X-Git-Oldrev: $oldrev
186 X-Git-Newrev: $newrev
187
188 This is an automated email from the git hooks/post-receive script. It was
189 generated because a ref change was pushed to the repository containing
190 the project "$projectdesc".
191
192 The $refname_type, $short_refname has been ${change_type}d
193 EOF
194 }
195
196 generate_email_footer()
197 {
198 cat <<-EOF
199
200
201 hooks/post-receive
202 --
203 $projectdesc
204 EOF
205 }
206
207 # --------------- Branches
208
209 #
210 # Called for the creation of a branch
211 #
212 generate_create_branch_email()
213 {
214 # This is a new branch and so oldrev is not valid
215 echo " at $newrev ($newrev_type)"
216 echo ""
217
218 echo $LOGBEGIN
219 # This shows all log entries that are not already covered by
220 # another ref - i.e. commits that are now accessible from this
221 # ref that were previously not accessible (see generate_update_branch_email
222 # for the explanation of this command)
223 git rev-parse --not --branches | grep -v $(git rev-parse $refname) |
224 git rev-list --pretty --stdin $newrev
225 echo $LOGEND
226 }
227
228 #
229 # Called for the change of a pre-existing branch
230 #
231 generate_update_branch_email()
232 {
233 # Consider this:
234 # 1 --- 2 --- O --- X --- 3 --- 4 --- N
235 #
236 # O is $oldrev for $refname
237 # N is $newrev for $refname
238 # X is a revision pointed to by some other ref, for which we may
239 # assume that an email has already been generated.
240 # In this case we want to issue an email containing only revisions
241 # 3, 4, and N. Given (almost) by
242 #
243 # git-rev-list N ^O --not --all
244 #
245 # The reason for the "almost", is that the "--not --all" will take
246 # precedence over the "N", and effectively will translate to
247 #
248 # git-rev-list N ^O ^X ^N
249 #
250 # So, we need to build up the list more carefully. git-rev-parse will
251 # generate a list of revs that may be fed into git-rev-list. We can get
252 # it to make the "--not --all" part and then filter out the "^N" with:
253 #
254 # git-rev-parse --not --all | grep -v N
255 #
256 # Then, using the --stdin switch to git-rev-list we have effectively
257 # manufactured
258 #
259 # git-rev-list N ^O ^X
260 #
261 # This leaves a problem when someone else updates the repository
262 # while this script is running. Their new value of the ref we're working
263 # on would be included in the "--not --all" output; and as our $newrev
264 # would be an ancestor of that commit, it would exclude all of our
265 # commits. What we really want is to exclude the current value of
266 # $refname from the --not list, rather than N itself. So:
267 #
268 # git-rev-parse --not --all | grep -v $(git-rev-parse $refname)
269 #
270 # Get's us to something pretty safe (apart from the small time between
271 # refname being read, and git-rev-parse running - for that, I give up)
272 #
273 #
274 # Next problem, consider this:
275 # * --- B --- * --- O ($oldrev)
276 # \
277 # * --- X --- * --- N ($newrev)
278 #
279 # That is to say, there is no guarantee that oldrev is a strict subset of
280 # newrev (it would have required a --force, but that's allowed). So, we
281 # can't simply say rev-list $oldrev..$newrev. Instead we find the common
282 # base of the two revs and list from there.
283 #
284 # As above, we need to take into account the presence of X; if another
285 # branch is already in the repository and points at some of the revisions
286 # that we are about to output - we don't want them. The solution is as
287 # before: git-rev-parse output filtered.
288 #
289 # Finally, tags:
290 # 1 --- 2 --- O --- T --- 3 --- 4 --- N
291 #
292 # Tags pushed into the repository generate nice shortlog emails that
293 # summarise the commits between them and the previous tag. However,
294 # those emails don't include the full commit messages that we output
295 # for a branch update. Therefore we still want to output revisions
296 # that have been output on a tag email.
297 #
298 # Luckily, git-rev-parse includes just the tool. Instead of using "--all"
299 # we use "--branches"; this has the added benefit that "remotes/" will
300 # be ignored as well.
301
302 # List all of the revisions that were removed by this update, in a fast forward
303 # update, this list will be empty, because rev-list O ^N is empty. For a non
304 # fast forward, O ^N is the list of removed revisions
305 fast_forward=""
306 rev=""
307 for rev in $(git rev-list $newrev..$oldrev)
308 do
309 revtype=$(git cat-file -t "$rev")
310 echo " discards $rev ($revtype)"
311 done
312 if [ -z "$rev" ]; then
313 fast_forward=1
314 fi
315
316 # List all the revisions from baserev to newrev in a kind of
317 # "table-of-contents"; note this list can include revisions that have
318 # already had notification emails and is present to show the full detail
319 # of the change from rolling back the old revision to the base revision and
320 # then forward to the new revision
321 for rev in $(git rev-list $oldrev..$newrev)
322 do
323 revtype=$(git cat-file -t "$rev")
324 echo " via $rev ($revtype)"
325 done
326
327 if [ -z "$fastforward" ]; then
328 echo " from $oldrev ($oldrev_type)"
329 else
330 # 1. Existing revisions were removed. In this case newrev is a
331 # subset of oldrev - this is the reverse of a fast-forward,
332 # a rewind
333 # 2. New revisions were added on top of an old revision, this is
334 # a rewind and addition.
335
336 # (1) certainly happened, (2) possibly. When (2) hasn't happened,
337 # we set a flag to indicate that no log printout is required.
338
339 echo ""
340
341 # Find the common ancestor of the old and new revisions and compare
342 # it with newrev
343 baserev=$(git merge-base $oldrev $newrev)
344 rewind_only=""
345 if [ "$baserev" = "$newrev" ]; then
346 echo "This update discarded existing revisions and left the branch pointing at"
347 echo "a previous point in the repository history."
348 echo ""
349 echo " * -- * -- N ($newrev)"
350 echo " \\"
351 echo " O -- O -- O ($oldrev)"
352 echo ""
353 echo "The removed revisions are not necessarilly gone - if another reference"
354 echo "still refers to them they will stay in the repository."
355 rewind_only=1
356 else
357 echo "This update added new revisions after undoing existing revisions. That is"
358 echo "to say, the old revision is not a strict subset of the new revision. This"
359 echo "situation occurs when you --force push a change and generate a repository"
360 echo "containing something like this:"
361 echo ""
362 echo " * -- * -- B -- O -- O -- O ($oldrev)"
363 echo " \\"
364 echo " N -- N -- N ($newrev)"
365 echo ""
366 echo "When this happens we assume that you've already had alert emails for all"
367 echo "of the O revisions, and so we here report only the revisions in the N"
368 echo "branch from the common base, B."
369 fi
370 fi
371
372 echo ""
373 if [ -z "$rewind_only" ]; then
374 echo "Those revisions listed above that are new to this repository have"
375 echo "not appeared on any other notification email; so we list those"
376 echo "revisions in full, below."
377
378 echo ""
379 echo $LOGBEGIN
380 git rev-parse --not --branches | grep -v $(git rev-parse $refname) |
381 git rev-list --pretty --stdin $oldrev..$newrev
382
383 # XXX: Need a way of detecting whether git rev-list actually outputted
384 # anything, so that we can issue a "no new revisions added by this
385 # update" message
386
387 echo $LOGEND
388 else
389 echo "No new revisions were added by this update."
390 fi
391
392 # The diffstat is shown from the old revision to the new revision. This
393 # is to show the truth of what happened in this change. There's no point
394 # showing the stat from the base to the new revision because the base
395 # is effectively a random revision at this point - the user will be
396 # interested in what this revision changed - including the undoing of
397 # previous revisions in the case of non-fast forward updates.
398 echo ""
399 echo "Summary of changes:"
400 git diff-tree --stat --summary --find-copies-harder $oldrev..$newrev
401 }
402
403 #
404 # Called for the deletion of a branch
405 #
406 generate_delete_branch_email()
407 {
408 echo " was $oldrev"
409 echo ""
410 echo $LOGEND
411 git show -s --pretty=oneline $oldrev
412 echo $LOGEND
413 }
414
415 # --------------- Annotated tags
416
417 #
418 # Called for the creation of an annotated tag
419 #
420 generate_create_atag_email()
421 {
422 echo " at $newrev ($newrev_type)"
423
424 generate_atag_email
425 }
426
427 #
428 # Called for the update of an annotated tag (this is probably a rare event
429 # and may not even be allowed)
430 #
431 generate_update_atag_email()
432 {
433 echo " to $newrev ($newrev_type)"
434 echo " from $oldrev (which is now obsolete)"
435
436 generate_atag_email
437 }
438
439 #
440 # Called when an annotated tag is created or changed
441 #
442 generate_atag_email()
443 {
444 # Use git-for-each-ref to pull out the individual fields from the tag
445 eval $(git for-each-ref --shell --format='
446 tagobject=%(*objectname)
447 tagtype=%(*objecttype)
448 tagger=%(taggername)
449 tagged=%(taggerdate)' $refname
450 )
451
452 echo " tagging $tagobject ($tagtype)"
453 case "$tagtype" in
454 commit)
455 # If the tagged object is a commit, then we assume this is a
456 # release, and so we calculate which tag this tag is replacing
457 prevtag=$(git describe --abbrev=0 $newrev^ 2>/dev/null)
458
459 if [ -n "$prevtag" ]; then
460 echo " replaces $prevtag"
461 fi
462 ;;
463 *)
464 echo " length $(git cat-file -s $tagobject) bytes"
465 ;;
466 esac
467 echo " tagged by $tagger"
468 echo " on $tagged"
469
470 echo ""
471 echo $LOGBEGIN
472
473 # Show the content of the tag message; this might contain a change log
474 # or release notes so is worth displaying.
475 git cat-file tag $newrev | sed -e '1,/^$/d'
476
477 echo ""
478 case "$tagtype" in
479 commit)
480 # Only commit tags make sense to have rev-list operations performed
481 # on them
482 if [ -n "$prevtag" ]; then
483 # Show changes since the previous release
484 git rev-list --pretty=short "$prevtag..$newrev" | git shortlog
485 else
486 # No previous tag, show all the changes since time began
487 git rev-list --pretty=short $newrev | git shortlog
488 fi
489 ;;
490 *)
491 # XXX: Is there anything useful we can do for non-commit objects?
492 ;;
493 esac
494
495 echo $LOGEND
496 }
497
498 #
499 # Called for the deletion of an annotated tag
500 #
501 generate_delete_atag_email()
502 {
503 echo " was $oldrev"
504 echo ""
505 echo $LOGEND
506 git show -s --pretty=oneline $oldrev
507 echo $LOGEND
508 }
509
510 # --------------- General references
511
512 #
513 # Called when any other type of reference is created (most likely a
514 # non-annotated tag)
515 #
516 generate_create_general_email()
517 {
518 echo " at $newrev ($newrev_type)"
519
520 generate_general_email
521 }
522
523 #
524 # Called when any other type of reference is updated (most likely a
525 # non-annotated tag)
526 #
527 generate_update_general_email()
528 {
529 echo " to $newrev ($newrev_type)"
530 echo " from $oldrev"
531
532 generate_general_email
533 }
534
535 #
536 # Called for creation or update of any other type of reference
537 #
538 generate_general_email()
539 {
540 # Unannotated tags are more about marking a point than releasing a version;
541 # therefore we don't do the shortlog summary that we do for annotated tags
542 # above - we simply show that the point has been marked, and print the log
543 # message for the marked point for reference purposes
544 #
545 # Note this section also catches any other reference type (although there
546 # aren't any) and deals with them in the same way.
547
548 echo ""
549 if [ "$newrev_type" = "commit" ]; then
550 echo $LOGBEGIN
551 git show --no-color --root -s $newrev
552 echo $LOGEND
553 else
554 # What can we do here? The tag marks an object that is not a commit,
555 # so there is no log for us to display. It's probably not wise to
556 # output git-cat-file as it could be a binary blob. We'll just say how
557 # big it is
558 echo "$newrev is a $newrev_type, and is $(git cat-file -s $newrev) bytes long."
559 fi
560 }
561
562 #
563 # Called for the deletion of any other type of reference
564 #
565 generate_delete_general_email()
566 {
567 echo " was $oldrev"
568 echo ""
569 echo $LOGEND
570 git show -s --pretty=oneline $oldrev
571 echo $LOGEND
572 }
573
574 # ---------------------------- main()
575
576 # --- Constants
577 EMAILPREFIX="[SCM] "
578 LOGBEGIN="- Log -----------------------------------------------------------------"
579 LOGEND="-----------------------------------------------------------------------"
580
581 # --- Config
582 # Set GIT_DIR either from the working directory, or from the environment
583 # variable.
584 GIT_DIR=$(git rev-parse --git-dir 2>/dev/null)
585 if [ -z "$GIT_DIR" ]; then
586 echo >&2 "fatal: post-receive: GIT_DIR not set"
587 exit 1
588 fi
589
590 projectdesc=$(sed -e '1p' "$GIT_DIR/description")
591 # Check if the description is unchanged from it's default, and shorten it to a
592 # more manageable length if it is
593 if expr "$projectdesc" : "Unnamed repository.*$" >/dev/null
594 then
595 projectdesc="UNNAMED PROJECT"
596 fi
597
598 recipients=$(git repo-config hooks.mailinglist)
599 announcerecipients=$(git repo-config hooks.announcelist)
600 envelopesender=$(git-repo-config hooks.envelopesender)
601
602 # --- Main loop
603 # Allow dual mode: run from the command line just like the update hook, or if
604 # no arguments are given then run as a hook script
605 if [ -n "$1" -a -n "$2" -a -n "$3" ]; then
606 # Output to the terminal in command line mode - if someone wanted to
607 # resend an email; they could redirect the output to sendmail themselves
608 PAGER= generate_email $2 $3 $1
609 else
610 if [ -n "$envelopesender" ]; then
611 envelopesender="-f '$envelopesender'"
612 fi
613
614 while read oldrev newrev refname
615 do
616 generate_email $oldrev $newrev $refname |
617 /usr/sbin/sendmail -t $envelopesender
618 done
619 fi