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>
This commit is contained in:
Andy Parkins 2007-04-26 22:36:24 +01:00 committed by Junio C Hamano
parent 8e404f82ab
commit 024e5b31af

View file

@ -327,36 +327,67 @@ generate_update_branch_email()
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 ""
echo "This update added new revisions after undoing old revisions. That is to"
echo "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"
echo "repository 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."
# 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 ($newrev)"
echo ""
echo "When this happens we assume that you've already had alert emails for all"
echo "of the O revisions, and so we here report only the revisions in the N"
echo "branch from the common base, B."
fi
fi
echo ""
echo "Those revisions listed above that are new to this repository have"
echo "not appeared on any other notification email; so we list those"
echo "revisions in full, below."
if [ -z "$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
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
# 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
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