Subject: Re: 'git commit' duplicates parents?

From: Dan Holmsand <[email-masked]>
Date: Mon, 20 Jun 2005 20:52:38 +0200

Linus Torvalds wrote:
> 
> [ Side note: I should make "git-resolve-script" run "git-rev-parse" on its
>   arguments, so that it would expand HEAD and MERGE_HEAD on its own. Maybe 
>   somebody who is interested in this script might want to do that? Hint 
>   hint. ]

Got it. Included below.

> Note how we could make both of us happy by saving that temporary 
> MERGE_HEAD information somewhere _else_ instead. Maybe the answer is to 
> only use "MERGE_HEAD" for the "merge manually" case, and use something 
> else for the "this was the merge you tried to do last" case?

I like the "everybody happy" idea...

How about "LAST_MERGE"? And something like this?

/dan

---

[PATCH] git-resolve-script: Add LAST_MERGE and use git-rev-parse

Make git-resolve-script only write MERGE_HEAD if a merge actually
occurred. All merge failures leave ORIG_HEAD and LAST_MERGE
behind (instead of ORIG_HEAD and MERGE_HEAD).

Use git-rev-parse to expand arguments (and check for bad ones).

Signed-off-by: Dan Holmsand <[email-masked]>
diff --git a/git-resolve-script b/git-resolve-script
--- a/git-resolve-script
+++ b/git-resolve-script
@@ -4,26 +4,31 @@
 #
 # Resolve two trees.
 #
-head="$1"
-merge="$2"
+head=$(git-rev-parse --revs-only "$1")
+merge=$(git-rev-parse --revs-only "$2")
 merge_repo="$3"
 
 : ${GIT_DIR=.git}
 : ${GIT_OBJECT_DIRECTORY="${SHA1_FILE_DIRECTORY-"$GIT_DIR/objects"}"}
 
-rm -f "$GIT_DIR"/MERGE_HEAD "$GIT_DIR"/ORIG_HEAD
-echo $head > "$GIT_DIR"/ORIG_HEAD
-echo $merge > "$GIT_DIR"/MERGE_HEAD
+dropheads() {
+	rm -f -- "$GIT_DIR/ORIG_HEAD" "$GIT_DIR/MERGE_HEAD" \
+		"$GIT_DIR/LAST_MERGE" || exit 1
+}
 
 #
 # The remote name is just used for the message,
 # but we do want it.
 #
-if [ "$merge_repo" == "" ]; then
+if [ -z "$head" -o -z "$merge" -o -z "$merge_repo" ]; then
 	echo "git-resolve-script <head> <remote> <merge-repo-name>"
 	exit 1
 fi
 
+dropheads
+echo $head > "$GIT_DIR"/ORIG_HEAD
+echo $merge > "$GIT_DIR"/LAST_MERGE
+
 common=$(git-merge-base $head $merge)
 if [ -z "$common" ]; then
 	echo "Unable to find common commit between" $merge $head
@@ -32,7 +37,7 @@ fi
 
 if [ "$common" == "$merge" ]; then
 	echo "Already up-to-date. Yeeah!"
-	rm -f -- "$GIT_DIR/ORIG_HEAD" "$GIT_DIR/MERGE_HEAD"
+	dropheads
 	exit 0
 fi
 if [ "$common" == "$head" ]; then
@@ -40,7 +45,7 @@ if [ "$common" == "$head" ]; then
 	git-read-tree -u -m $head $merge || exit 1
 	echo $merge > "$GIT_DIR"/HEAD
 	git-diff-tree -p ORIG_HEAD HEAD | git-apply --stat
-	rm -f -- "$GIT_DIR/ORIG_HEAD" "$GIT_DIR/MERGE_HEAD"
+	dropheads
 	exit 0
 fi
 echo "Trying to merge $merge into $head"
@@ -51,6 +56,7 @@ if [ $? -ne 0 ]; then
 	echo "Simple merge failed, trying Automatic merge"
 	git-merge-cache -o git-merge-one-file-script -a
 	if [ $? -ne 0 ]; then
+		echo $merge > "$GIT_DIR"/MERGE_HEAD
 		echo "Automatic merge failed, fix up by hand"
 		exit 1
 	fi
@@ -60,4 +66,4 @@ result_commit=$(echo "$merge_msg" | git-
 echo "Committed merge $result_commit"
 echo $result_commit > "$GIT_DIR"/HEAD
 git-diff-tree -p $head $result_commit | git-apply --stat
-rm -f -- "$GIT_DIR/ORIG_HEAD" "$GIT_DIR/MERGE_HEAD"
+dropheads