Re: [PATCH] Convert emailing part of hooks--update to hooks--post-receive

>  git rev-parse --not --all | grep -v $(<$refname) |
>  git rev-list --pretty --stdin $newrev --not $baserev
>
> This uses git-rev-parse followed by grep to filter out the revision of
> the ref in question before it gets to rev-list and inhibits the output
> of itself.  By using $(<$refname) rather than $newrev as the filter, it
> also takes care of the situation where another update to the same ref
> has been made since $refname was $newrev.

> +generate_email()
> +{
> ...
> +		refs/remotes/*,commit)
> +			# tracking branch
> +			refname_type="tracking branch"
> +			short_refname=${refname##refs/remotes/}
> +			echo "*** Push-update of tracking branch, $refname"
> +			echo "***  - no email generated." >&2

> +			exit 0
> +			;;
> +		*)
> +			# Anything else (is there anything else?)
> +			echo "*** Unknown type of update to $refname ($rev_type)" >&2
> +			echo "***  - no email generated"

> +			exit 1
> +			;;
> +	esac
> +
> +	# Check if we've got anyone to send to
> +	if [ -z "$recipients" ]; then
> +		echo "*** hooks.recipients is not set so no email will be sent" >&2
> +		echo "*** for $refname update $oldrev->$newrev" >&2
> +		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 | grep "^Commit: " | sed -e "s/^Commit: //")

> +	# 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 - object oriented programming
> +	# in a script - overkill perhaps?

> +	fn_name=general
> +	case "$refname_type" in
> +		# --- Branches
> +		"tracking branch"|branch)
> +			fn_name=branch
> +			;;
> +		# --- Annotated tags
> +		"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
> +	--
> +	Git Source Code Management System
> +	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_DIR}/$refname) |
> +	git rev-list --pretty --stdin $newrev --not $baserev
> +	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.

> +	# Next problem, consider this:
> +	#   * --- B --- * --- O ($oldrev)
> +	#          \
> +	#           * --- X --- * --- N ($newrev)
> +	#
> +	# That is to say, there is no guarantee that newrev is a strict subset of
> +	# oldrev (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.

> +
> +	baserev=$(git merge-base $oldrev $newrev)
> +
> +	# 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 $newrev --not $baserev)
> +	do
> +		revtype=$(git cat-file -t "$rev")
> +		echo "       via  $rev ($revtype)"
> +	done
> +
> +	# If the baserev is equal to the oldrev, then we know that this was a
> +	# fast forward update; otherwise "--force" was used, and we give a more
> +	# detailed explanation of what happened.

> +	if [ "$baserev" = "$oldrev" ]; then
> +		echo "      from  $oldrev ($oldrev_type)"
> +	else
> +		echo "      from  $baserev"
> +		echo "  discards  $oldrev ($oldrev_type) and its branch"
> +		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 ($baserev),"
> +		echo "up to the new branch endpoint."
> +	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."
> +
> +	echo ""
> +	echo $LOGBEGIN
> +	git rev-parse --not --branches | grep -v $(<${GIT_DIR}/$refname) |
> +	git rev-list --pretty --stdin $newrev --not $baserev

> +
> +	# 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
> +
> +	# 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.

> +
> +#
> +# Called for the deletion of a branch
> +#
> +generate_delete_branch_email()
> +{
> +	echo "       was  $oldrev"
> +	echo ""
> +}

> +
> +# --------------- 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 --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.  "tail -n +5" is there to
> +	# remove the first 4 lines of the tag object, those details have
> +	# already been summarised above
> +	git cat-file tag $newrev | tail -q -n +5

> +
> +	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?
> +		;;

> +# --- 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 "fatal: post-receive: GIT_DIR not set"
> +	exit 1
> +fi
> +
> +projectdesc=$(cat $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