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authorJunio C Hamano <>2005-09-08 20:47:12 (GMT)
committerJunio C Hamano <>2005-09-11 01:30:41 (GMT)
commit91063bbc6c4187184e94ebc4ab2b807e6d53cd0a (patch)
tree473b699f8570ca750aa44689ca63875ff10136bf /
parentbb97a2a804e0afdd686ed9f18fed2ddc15833540 (diff)
Multi-backend merge driver.
The new command 'git merge' takes the current head and one or more remote heads, with the commit log message for the automated case. If the heads being merged are simple fast-forwards, it acts the same way as the current 'git resolve'. Otherwise, it tries different merge strategies and takes the result from the one that succeeded auto-merging, if there is any. If no merge strategy succeeds auto-merging, their results are evaluated for number of paths needed for hand resolving, and the one with the least number of such paths is left in the working tree. The user is asked to resolve them by hand and make a commit manually. The calling convention from the 'git merge' driver to merge strategy programs is very simple: - A strategy program is to be called 'git-merge-<strategy>'. - They take input of this form: <common1> <common2> ... '--' <head> <remote1> <remote2>... That is, one or more the common ancestors, double dash, the current head, and one or more remote heads being merged into the current branch. - Before a strategy program is called, the working tree is matched to the current <head>. - The strategy program exits with status code 0 when it successfully auto-merges the given heads. It should do update-cache for all the merged paths when it does so -- the index file will be used to record the merge result as a commit by the driver. - The strategy program exits with status code 1 when it leaves conflicts behind. It should do update-cache for all the merged paths that it successfully auto-merged, and leave the cache entry in the index file as the same as <head> for paths it could not auto-merge, and leave its best-effort result with conflict markers in the working tree when it does so. - The strategy program exists with status code other than 0 or 1 if it does not handle the given merge at all. As examples, this commit comes with merge strategies based on 'git resolve' and 'git octopus'. Signed-off-by: Junio C Hamano <>
Diffstat (limited to '')
1 files changed, 80 insertions, 0 deletions
diff --git a/ b/
new file mode 100755
index 0000000..f0a19b4
--- /dev/null
+++ b/
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+# Copyright (c) 2005 Linus Torvalds
+# Resolve two trees.
+# The first parameters up to -- are merge bases; the rest are heads.
+bases= head= remotes= sep_seen=
+for arg
+ case ",$sep_seen,$head,$arg," in
+ *,--,)
+ sep_seen=yes
+ ;;
+ ,yes,,*)
+ head=$arg
+ ;;
+ ,yes,*)
+ remotes="$remotes$arg "
+ ;;
+ *)
+ bases="$bases$arg "
+ ;;
+ esac
+# Give up if we are given more than two remotes -- not handling octopus.
+case "$remotes" in
+?*' '?*)
+ exit 2 ;;
+# Find an optimum merge base if there are more than one candidates.
+case "$bases" in
+?*' '?*)
+ echo "Trying to find the optimum merge base."
+ G=.tmp-index$$
+ best=
+ best_cnt=-1
+ for c in $bases
+ do
+ rm -f $G
+ GIT_INDEX_FILE=$G git-read-tree -m $c $head $remotes \
+ 2>/dev/null || continue
+ # Count the paths that are unmerged.
+ cnt=`GIT_INDEX_FILE=$G git-ls-files --unmerged | wc -l`
+ if test $best_cnt -le 0 -o $cnt -le $best_cnt
+ then
+ best=$c
+ best_cnt=$cnt
+ if test "$best_cnt" -eq 0
+ then
+ # Cannot do any better than all trivial merge.
+ break
+ fi
+ fi
+ done
+ rm -f $G
+ common="$best"
+ ;;
+ common="$bases"
+ ;;
+git-update-index --refresh 2>/dev/null
+git-read-tree -u -m $common $head $remotes || exit 2
+echo "Trying simple merge."
+if result_tree=$(git-write-tree 2>/dev/null)
+ exit 0
+ echo "Simple merge failed, trying Automatic merge."
+ if git-merge-index -o git-merge-one-file -a
+ then
+ exit 0
+ else
+ exit 1
+ fi