git-commit-vandalism/contrib/hooks/post-receive-email
Andy Parkins 024e5b31af post-receive-email example hook: detect rewind-only updates and output sensible message
Sometimes a non-fast-forward update doesn't add new commits, it merely
removes old commits.  This patch adds support for detecting that and
outputting a more correct message.

Signed-off-by: Andy Parkins <andyparkins@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-04-26 20:59:49 -07:00

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#!/bin/sh
#
# Copyright (c) 2007 Andy Parkins
#
# An example hook script to mail out commit update information. This hook sends emails
# listing new revisions to the repository introduced by the change being reported. The
# rule is that (for branch updates) each commit will appear on one email and one email
# only.
#
# This hook is stored in the contrib/hooks directory. Your distribution will have put
# this somewhere standard. You should make this script executable then link to it in
# the repository you would like to use it in. For example, on debian the hook is stored
# in /usr/share/doc/git-core/contrib/hooks/post-receive-email:
#
# chmod a+x post-receive-email
# cd /path/to/your/repository.git
# ln -sf /usr/share/doc/git-core/contrib/hooks/post-receive-email hooks/post-receive
#
# This hook script assumes it is enabled on the central repository of a project, with
# all users pushing only to it and not between each other. It will still work if you
# don't operate in that style, but it would become possible for the email to be from
# someone other than the person doing the push.
#
# Config
# ------
# hooks.mailinglist
# This is the list that all pushes will go to; leave it blank to not send
# emails for every ref update.
# hooks.announcelist
# This is the list that all pushes of annotated tags will go to. Leave it
# blank to default to the mailinglist field. The announce emails lists the
# short log summary of the changes since the last annotated tag.
# hook.envelopesender
# If set then the -f option is passed to sendmail to allow the envelope sender
# address to be set
#
# Notes
# -----
# All emails have their subjects prefixed with "[SCM]" to aid filtering.
# All emails include the headers "X-Git-Refname", "X-Git-Oldrev",
# "X-Git-Newrev", and "X-Git-Reftype" to enable fine tuned filtering and
# give information for debugging.
#
# ---------------------------- Functions
#
# Top level email generation function. This decides what type of update
# this is and calls the appropriate body-generation routine after outputting
# the common header
#
# Note this function doesn't actually generate any email output, that is taken
# care of by the functions it calls:
# - generate_email_header
# - generate_create_XXXX_email
# - generate_update_XXXX_email
# - generate_delete_XXXX_email
# - generate_email_footer
#
generate_email()
{
# --- Arguments
oldrev=$(git rev-parse $1)
newrev=$(git rev-parse $2)
refname="$3"
# --- Interpret
# 0000->1234 (create)
# 1234->2345 (update)
# 2345->0000 (delete)
if expr "$oldrev" : '0*$' >/dev/null
then
change_type="create"
else
if expr "$newrev" : '0*$' >/dev/null
then
change_type="delete"
else
change_type="update"
fi
fi
# --- Get the revision types
newrev_type=$(git cat-file -t $newrev 2> /dev/null)
oldrev_type=$(git cat-file -t "$oldrev" 2> /dev/null)
case "$change_type" in
create|update)
rev="$newrev"
rev_type="$newrev_type"
;;
delete)
rev="$oldrev"
rev_type="$oldrev_type"
;;
esac
# The revision type tells us what type the commit is, combined with
# the location of the ref we can decide between
# - working branch
# - tracking branch
# - unannoted tag
# - annotated tag
case "$refname","$rev_type" in
refs/tags/*,commit)
# un-annotated tag
refname_type="tag"
short_refname=${refname##refs/tags/}
;;
refs/tags/*,tag)
# annotated tag
refname_type="annotated tag"
short_refname=${refname##refs/tags/}
# change recipients
if [ -n "$announcerecipients" ]; then
recipients="$announcerecipients"
fi
;;
refs/heads/*,commit)
# branch
refname_type="branch"
short_refname=${refname##refs/heads/}
;;
refs/remotes/*,commit)
# tracking branch
refname_type="tracking branch"
short_refname=${refname##refs/remotes/}
echo >&2 "*** Push-update of tracking branch, $refname"
echo >&2 "*** - no email generated."
exit 0
;;
*)
# Anything else (is there anything else?)
echo >&2 "*** Unknown type of update to $refname ($rev_type)"
echo >&2 "*** - no email generated"
exit 1
;;
esac
# Check if we've got anyone to send to
if [ -z "$recipients" ]; then
echo >&2 "*** hooks.recipients is not set so no email will be sent"
echo >&2 "*** for $refname update $oldrev->$newrev"
exit 0
fi
# Email parameters
# The committer will be obtained from the latest existing rev; so
# for a deletion it will be the oldrev, for the others, then newrev
committer=$(git show --pretty=full -s $rev | sed -ne "s/^Commit: //p" |
sed -ne 's/\(.*\) </"\1" </p')
# The email subject will contain the best description of the ref
# that we can build from the parameters
describe=$(git describe $rev 2>/dev/null)
if [ -z "$describe" ]; then
describe=$rev
fi
generate_email_header
# Call the correct body generation function
fn_name=general
case "$refname_type" in
"tracking branch"|branch)
fn_name=branch
;;
"annotated tag")
fn_name=atag
;;
esac
generate_${change_type}_${fn_name}_email
generate_email_footer
}
generate_email_header()
{
# --- Email (all stdout will be the email)
# Generate header
cat <<-EOF
From: $committer
To: $recipients
Subject: ${EMAILPREFIX}$projectdesc $refname_type, $short_refname, ${change_type}d. $describe
X-Git-Refname: $refname
X-Git-Reftype: $refname_type
X-Git-Oldrev: $oldrev
X-Git-Newrev: $newrev
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "$projectdesc".
The $refname_type, $short_refname has been ${change_type}d
EOF
}
generate_email_footer()
{
cat <<-EOF
hooks/post-receive
--
$projectdesc
EOF
}
# --------------- Branches
#
# Called for the creation of a branch
#
generate_create_branch_email()
{
# This is a new branch and so oldrev is not valid
echo " at $newrev ($newrev_type)"
echo ""
echo $LOGBEGIN
# This shows all log entries that are not already covered by
# another ref - i.e. commits that are now accessible from this
# ref that were previously not accessible (see generate_update_branch_email
# for the explanation of this command)
git rev-parse --not --branches | grep -v $(git rev-parse $refname) |
git rev-list --pretty --stdin $newrev
echo $LOGEND
}
#
# Called for the change of a pre-existing branch
#
generate_update_branch_email()
{
# Consider this:
# 1 --- 2 --- O --- X --- 3 --- 4 --- N
#
# O is $oldrev for $refname
# N is $newrev for $refname
# X is a revision pointed to by some other ref, for which we may
# assume that an email has already been generated.
# In this case we want to issue an email containing only revisions
# 3, 4, and N. Given (almost) by
#
# git-rev-list N ^O --not --all
#
# The reason for the "almost", is that the "--not --all" will take
# precedence over the "N", and effectively will translate to
#
# git-rev-list N ^O ^X ^N
#
# So, we need to build up the list more carefully. git-rev-parse will
# generate a list of revs that may be fed into git-rev-list. We can get
# it to make the "--not --all" part and then filter out the "^N" with:
#
# git-rev-parse --not --all | grep -v N
#
# Then, using the --stdin switch to git-rev-list we have effectively
# manufactured
#
# git-rev-list N ^O ^X
#
# This leaves a problem when someone else updates the repository
# while this script is running. Their new value of the ref we're working
# on would be included in the "--not --all" output; and as our $newrev
# would be an ancestor of that commit, it would exclude all of our
# commits. What we really want is to exclude the current value of
# $refname from the --not list, rather than N itself. So:
#
# git-rev-parse --not --all | grep -v $(git-rev-parse $refname)
#
# Get's us to something pretty safe (apart from the small time between
# refname being read, and git-rev-parse running - for that, I give up)
#
#
# Next problem, consider this:
# * --- B --- * --- O ($oldrev)
# \
# * --- X --- * --- N ($newrev)
#
# That is to say, there is no guarantee that oldrev is a strict subset of
# newrev (it would have required a --force, but that's allowed). So, we
# can't simply say rev-list $oldrev..$newrev. Instead we find the common
# base of the two revs and list from there.
#
# As above, we need to take into account the presence of X; if another
# branch is already in the repository and points at some of the revisions
# that we are about to output - we don't want them. The solution is as
# before: git-rev-parse output filtered.
#
# Finally, tags:
# 1 --- 2 --- O --- T --- 3 --- 4 --- N
#
# Tags pushed into the repository generate nice shortlog emails that
# summarise the commits between them and the previous tag. However,
# those emails don't include the full commit messages that we output
# for a branch update. Therefore we still want to output revisions
# that have been output on a tag email.
#
# Luckily, git-rev-parse includes just the tool. Instead of using "--all"
# we use "--branches"; this has the added benefit that "remotes/" will
# be ignored as well.
# List all of the revisions that were removed by this update, in a fast forward
# update, this list will be empty, because rev-list O ^N is empty. For a non
# fast forward, O ^N is the list of removed revisions
fast_forward=""
rev=""
for rev in $(git rev-list $newrev..$oldrev)
do
revtype=$(git cat-file -t "$rev")
echo " discards $rev ($revtype)"
done
if [ -z "$rev" ]; then
fast_forward=1
fi
# List all the revisions from baserev to newrev in a kind of
# "table-of-contents"; note this list can include revisions that have
# already had notification emails and is present to show the full detail
# of the change from rolling back the old revision to the base revision and
# then forward to the new revision
for rev in $(git rev-list $oldrev..$newrev)
do
revtype=$(git cat-file -t "$rev")
echo " via $rev ($revtype)"
done
if [ -z "$fastforward" ]; then
echo " from $oldrev ($oldrev_type)"
else
# 1. Existing revisions were removed. In this case newrev is a
# subset of oldrev - this is the reverse of a fast-forward,
# a rewind
# 2. New revisions were added on top of an old revision, this is
# a rewind and addition.
# (1) certainly happened, (2) possibly. When (2) hasn't happened,
# we set a flag to indicate that no log printout is required.
echo ""
# Find the common ancestor of the old and new revisions and compare
# it with newrev
baserev=$(git merge-base $oldrev $newrev)
rewind_only=""
if [ "$baserev" = "$newrev" ]; then
echo "This update discarded existing revisions and left the branch pointing at"
echo "a previous point in the repository history."
echo ""
echo " * -- * -- N ($newrev)"
echo " \\"
echo " O -- O -- O ($oldrev)"
echo ""
echo "The removed revisions are not necessarilly gone - if another reference"
echo "still refers to them they will stay in the repository."
rewind_only=1
else
echo "This update added new revisions after undoing existing revisions. That is"
echo "to say, the old revision is not a strict subset of the new revision. This"
echo "situation occurs when you --force push a change and generate a repository"
echo "containing something like this:"
echo ""
echo " * -- * -- B -- O -- O -- O ($oldrev)"
echo " \\"
echo " N -- N -- N ($newrev)"
echo ""
echo "When this happens we assume that you've already had alert emails for all"
echo "of the O revisions, and so we here report only the revisions in the N"
echo "branch from the common base, B."
fi
fi
echo ""
if [ -z "$rewind_only" ]; then
echo "Those revisions listed above that are new to this repository have"
echo "not appeared on any other notification email; so we list those"
echo "revisions in full, below."
echo ""
echo $LOGBEGIN
git rev-parse --not --branches | grep -v $(git rev-parse $refname) |
git rev-list --pretty --stdin $oldrev..$newrev
# XXX: Need a way of detecting whether git rev-list actually outputted
# anything, so that we can issue a "no new revisions added by this
# update" message
echo $LOGEND
else
echo "No new revisions were added by this update."
fi
# The diffstat is shown from the old revision to the new revision. This
# is to show the truth of what happened in this change. There's no point
# showing the stat from the base to the new revision because the base
# is effectively a random revision at this point - the user will be
# interested in what this revision changed - including the undoing of
# previous revisions in the case of non-fast forward updates.
echo ""
echo "Summary of changes:"
git diff-tree --stat --summary --find-copies-harder $oldrev..$newrev
}
#
# Called for the deletion of a branch
#
generate_delete_branch_email()
{
echo " was $oldrev"
echo ""
echo $LOGEND
git show -s --pretty=oneline $oldrev
echo $LOGEND
}
# --------------- Annotated tags
#
# Called for the creation of an annotated tag
#
generate_create_atag_email()
{
echo " at $newrev ($newrev_type)"
generate_atag_email
}
#
# Called for the update of an annotated tag (this is probably a rare event
# and may not even be allowed)
#
generate_update_atag_email()
{
echo " to $newrev ($newrev_type)"
echo " from $oldrev (which is now obsolete)"
generate_atag_email
}
#
# Called when an annotated tag is created or changed
#
generate_atag_email()
{
# Use git-for-each-ref to pull out the individual fields from the tag
eval $(git for-each-ref --shell --format='
tagobject=%(*objectname)
tagtype=%(*objecttype)
tagger=%(taggername)
tagged=%(taggerdate)' $refname
)
echo " tagging $tagobject ($tagtype)"
case "$tagtype" in
commit)
# If the tagged object is a commit, then we assume this is a
# release, and so we calculate which tag this tag is replacing
prevtag=$(git describe --abbrev=0 $newrev^ 2>/dev/null)
if [ -n "$prevtag" ]; then
echo " replaces $prevtag"
fi
;;
*)
echo " length $(git cat-file -s $tagobject) bytes"
;;
esac
echo " tagged by $tagger"
echo " on $tagged"
echo ""
echo $LOGBEGIN
# Show the content of the tag message; this might contain a change log
# or release notes so is worth displaying.
git cat-file tag $newrev | sed -e '1,/^$/d'
echo ""
case "$tagtype" in
commit)
# Only commit tags make sense to have rev-list operations performed
# on them
if [ -n "$prevtag" ]; then
# Show changes since the previous release
git rev-list --pretty=short "$prevtag..$newrev" | git shortlog
else
# No previous tag, show all the changes since time began
git rev-list --pretty=short $newrev | git shortlog
fi
;;
*)
# XXX: Is there anything useful we can do for non-commit objects?
;;
esac
echo $LOGEND
}
#
# Called for the deletion of an annotated tag
#
generate_delete_atag_email()
{
echo " was $oldrev"
echo ""
echo $LOGEND
git show -s --pretty=oneline $oldrev
echo $LOGEND
}
# --------------- General references
#
# Called when any other type of reference is created (most likely a
# non-annotated tag)
#
generate_create_general_email()
{
echo " at $newrev ($newrev_type)"
generate_general_email
}
#
# Called when any other type of reference is updated (most likely a
# non-annotated tag)
#
generate_update_general_email()
{
echo " to $newrev ($newrev_type)"
echo " from $oldrev"
generate_general_email
}
#
# Called for creation or update of any other type of reference
#
generate_general_email()
{
# Unannotated tags are more about marking a point than releasing a version;
# therefore we don't do the shortlog summary that we do for annotated tags
# above - we simply show that the point has been marked, and print the log
# message for the marked point for reference purposes
#
# Note this section also catches any other reference type (although there
# aren't any) and deals with them in the same way.
echo ""
if [ "$newrev_type" = "commit" ]; then
echo $LOGBEGIN
git show --no-color --root -s $newrev
echo $LOGEND
else
# What can we do here? The tag marks an object that is not a commit,
# so there is no log for us to display. It's probably not wise to
# output git-cat-file as it could be a binary blob. We'll just say how
# big it is
echo "$newrev is a $newrev_type, and is $(git cat-file -s $newrev) bytes long."
fi
}
#
# Called for the deletion of any other type of reference
#
generate_delete_general_email()
{
echo " was $oldrev"
echo ""
echo $LOGEND
git show -s --pretty=oneline $oldrev
echo $LOGEND
}
# ---------------------------- main()
# --- Constants
EMAILPREFIX="[SCM] "
LOGBEGIN="- Log -----------------------------------------------------------------"
LOGEND="-----------------------------------------------------------------------"
# --- Config
# Set GIT_DIR either from the working directory, or from the environment
# variable.
GIT_DIR=$(git rev-parse --git-dir 2>/dev/null)
if [ -z "$GIT_DIR" ]; then
echo >&2 "fatal: post-receive: GIT_DIR not set"
exit 1
fi
projectdesc=$(sed -e '1p' "$GIT_DIR/description")
# Check if the description is unchanged from it's default, and shorten it to a
# more manageable length if it is
if expr "$projectdesc" : "Unnamed repository.*$" >/dev/null
then
projectdesc="UNNAMED PROJECT"
fi
recipients=$(git repo-config hooks.mailinglist)
announcerecipients=$(git repo-config hooks.announcelist)
envelopesender=$(git-repo-config hooks.envelopesender)
# --- Main loop
# Allow dual mode: run from the command line just like the update hook, or if
# no arguments are given then run as a hook script
if [ -n "$1" -a -n "$2" -a -n "$3" ]; then
# Output to the terminal in command line mode - if someone wanted to
# resend an email; they could redirect the output to sendmail themselves
PAGER= generate_email $2 $3 $1
else
if [ -n "$envelopesender" ]; then
envelopesender="-f '$envelopesender'"
fi
while read oldrev newrev refname
do
generate_email $oldrev $newrev $refname |
/usr/sbin/sendmail -t $envelopesender
done
fi