[PATCH] Fix default pull not to do an unintended Octopus.

From: Junio C Hamano <junkio@cox.net>
Date: Sep 27, 2005, 07:38 UTC
Message-ID: <7vu0g72c4y.fsf_-_@assigned-by-dhcp.cox.net>
In-Reply-To: <7vr7bba3lo.fsf@assigned-by-dhcp.cox.net>

This is what I ended up doing Sunday night before the discussion started, and what I still have in the proposed updates branch.

It implements the 'when puling using a shorthand without explicitly telling which refs to pull, only use the first ref found from Pull: lines for merging -- creating Octopus using all default refs is not useful 99.99% of the time' behaviour I outlined yesterday.

I think it could be modified without too much pain to take "which heads to use for merge by default" information from separate "Merge: " line as Jon proposed, if enough people like that idea better. Personally I do not think it would make much practical difference from the end users' point of view, but I've been proven wrong more often than not in the past, so...

As Pasky said in another thread, git-fetch is not the most elegantly written script on earth, and it is not my favorite script either -- it needs to do complex things, like interacting with the later git-pull stage.

------------ The refspecs specified in the .git/remotes/<remote> on the "Pull: " lines are for fetching multiple heads in one go, but most of the time making an Octopus out of them is not what is wanted. Make git-fetch leave the marker in .git/FETCH_HEAD file so that later stages can tell which heads are for merging and which are not.

Tom Prince made me realize how stupid the original behaviour was.

Signed-off-by: Junio C Hamano <junkio@cox.net>

---

 git-fetch.sh           |   32 ++++++++++++++++++++++++++++----
 git-fmt-merge-msg.perl |    4 +++-
 git-parse-remote.sh    |   11 +++++++++--
 git-pull.sh            |    4 +++-
 4 files changed, 43 insertions(+), 8 deletions(-)

44dbc712fe3dd045550123e1cc689c41482c62e5

diff --git a/git-fetch.sh b/git-fetch.sh
--- a/git-fetch.sh
+++ b/git-fetch.sh
@@ -54,6 +54,10 @@ append_fetch_head () {
     remote_name_="$3"
     remote_nick_="$4"
     local_name_="$5"
+    case "$6" in
+    t) not_for_merge_='not-for-merge' ;;
+    '') not_for_merge_= ;;
+    esac
 
     # remote-nick is the URL given on the command line (or a shorthand)
     # remote-name is the $GIT_DIR relative refs/ path we computed
@@ -78,10 +82,11 @@ append_fetch_head () {
     if git-cat-file commit "$head_" >/dev/null 2>&1
     then
 	headc_=$(git-rev-parse --verify "$head_^0") || exit
-	echo "$headc_	$note_" >>$GIT_DIR/FETCH_HEAD
+	echo "$headc_	$not_for_merge_	$note_" >>$GIT_DIR/FETCH_HEAD
 	echo >&2 "* committish: $head_"
 	echo >&2 "  $note_"
     else
+	echo "$head_	not-for-merge	$note_" >>$GIT_DIR/FETCH_HEAD
 	echo >&2 "* non-commit: $head_"
 	echo >&2 "  $note_"
     fi
@@ -157,6 +162,13 @@ do
 
     # These are relative path from $GIT_DIR, typically starting at refs/
     # but may be HEAD
+    if expr "$ref" : '\.' >/dev/null
+    then
+	not_for_merge=t
+	ref=$(expr "$ref" : '\.\(.*\)')
+    else
+	not_for_merge=
+    fi
     if expr "$ref" : '\+' >/dev/null
     then
 	single_force=t
@@ -216,7 +228,8 @@ do
 	continue ;;
     esac
 
-    append_fetch_head "$head" "$remote" "$remote_name" "$remote_nick" "$local_name"
+    append_fetch_head "$head" "$remote" \
+    	"$remote_name" "$remote_nick" "$local_name" "$not_for_merge"
 
 done
 
@@ -241,16 +254,27 @@ http://* | https://* | rsync://* )
 	    case "$ref" in
 	    +$remote_name:*)
 		single_force=t
+		not_for_merge=
+		found="$ref"
+		break ;;
+	    .+$remote_name:*)
+		single_force=t
+		not_for_merge=t
+		found="$ref"
+		break ;;
+	    .$remote_name:*)
+	        not_for_merge=t
 		found="$ref"
 		break ;;
 	    $remote_name:*)
+	    	not_for_merge=
 		found="$ref"
 		break ;;
 	    esac
 	done
-
 	local_name=$(expr "$found" : '[^:]*:\(.*\)')
-	append_fetch_head "$sha1" "$remote" "$remote_name" "$remote_nick" "$local_name"
+	append_fetch_head "$sha1" "$remote" \
+		"$remote_name" "$remote_nick" "$local_name" "$not_for_merge"
     done || exit
     ;;
 esac
diff --git a/git-fmt-merge-msg.perl b/git-fmt-merge-msg.perl
--- a/git-fmt-merge-msg.perl
+++ b/git-fmt-merge-msg.perl
@@ -31,6 +31,8 @@ while (<>) {
 	my ($bname, $tname, $gname, $src);
 	chomp;
 	s/^[0-9a-f]*	//;
+	next if (/^not-for-merge/);
+	s/^	//;
 	if (s/ of (.*)$//) {
 		$src = $1;
 	} else {
@@ -86,7 +88,7 @@ for my $src (@src) {
 			    $src{$src}{GENERIC});
 	my $this = join(', ', @this);
 	if ($src ne '.') {
-		$this .= " from $src";
+		$this .= " of $src";
 	}
 	push @msg, $this;
 }
diff --git a/git-parse-remote.sh b/git-parse-remote.sh
--- a/git-parse-remote.sh
+++ b/git-parse-remote.sh
@@ -65,8 +65,11 @@ get_remote_default_refs_for_push () {
 	esac
 }
 
-# Subroutine to canonicalize remote:local notation
+# Subroutine to canonicalize remote:local notation.
 canon_refs_list_for_fetch () {
+	# Leave only the first one alone; add prefix . to the rest
+	# to prevent the secondary branches to be merged by default.
+	dot_prefix=
 	for ref
 	do
 		force=
@@ -91,7 +94,8 @@ canon_refs_list_for_fetch () {
 		heads/* | tags/* ) local="refs/$local" ;;
 		*) local="refs/heads/$local" ;;
 		esac
-		echo "${force}${remote}:${local}"
+		echo "${dot_prefix}${force}${remote}:${local}"
+		dot_prefix=.
 	done
 }
 
@@ -107,6 +111,9 @@ get_remote_default_refs_for_fetch () {
 		echo "refs/heads/${remote_branch}:refs/heads/$1"
 		;;
 	remotes)
+		# This prefixes the second and later default refspecs
+		# with a '.', to signal git-fetch to mark them
+		# not-for-merge.
 		canon_refs_list_for_fetch $(sed -ne '/^Pull: */{
 						s///p
 					}' "$GIT_DIR/remotes/$1")
diff --git a/git-pull.sh b/git-pull.sh
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -24,7 +24,9 @@ then
 		die "You need to first update your working tree."
 fi
 
-merge_head=$(sed -e 's/	.*//' "$GIT_DIR"/FETCH_HEAD | tr '\012' ' ')
+merge_head=$(sed -e '/	not-for-merge	/d' \
+	-e 's/	.*//' "$GIT_DIR"/FETCH_HEAD | \
+	tr '\012' ' ')
 
 case "$merge_head" in
 '')