git-upload-pack: Support the multi_ack protocol

diff --git a/git-merge.sh b/git-merge.sh
index 7607e819c355fd30923c520b35ab4de7b918f013..6ad96ebfbb06697a0ad0875274022d9103b24d0a 100755 (executable)
--- a/git-merge.sh
+++ b/git-merge.sh
@@ -24,7 +24,9 @@ dropsave() {
 }
 
 savestate() {
-       git diff -r -z --name-only $head | cpio -0 -o >"$GIR_DIR/MERGE_SAVE"
+       # Stash away any local modifications.
+       git-diff-index -z --name-only $head |
+       cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
 }
 
 restorestate() {
@@ -36,10 +38,20 @@ restorestate() {
        fi
 }
 
-summary() {
+finish () {
+       test '' = "$2" || echo "$2"
+       case "$merge_msg" in
+       '')
+               echo "No merge message -- not updating HEAD"
+               ;;
+       *)
+               git-update-ref HEAD "$1" "$head" || exit 1
+               ;;
+       esac
+
        case "$no_summary" in
        '')
-               git-diff-tree -p -M $head "$1" |
+               git-diff-tree -p -M "$head" "$1" |
                git-apply --stat --summary
                ;;
        esac
@@ -101,12 +113,12 @@ echo "$head" >"$GIT_DIR/ORIG_HEAD"
 
 case "$#,$common" in
 *,'')
-       die "Unable to find common commit between $head_arg and $*"
+       # No common ancestors found. We need a real merge.
        ;;
 1,"$1")
        # If head can reach all the merge then we are up to date.
        # but first the most common case of merging one remote
-       echo "Already up-to-date. Yeeah!"
+       echo "Already up-to-date."
        dropsave
        exit 0
        ;;
@@ -114,16 +126,35 @@ case "$#,$common" in
        # Again the most common case of merging one remote.
        echo "Updating from $head to $1."
        git-update-index --refresh 2>/dev/null
-       git-read-tree -u -m $head "$1" || exit 1
-       git-rev-parse --verify "$1^0" > "$GIT_DIR/HEAD"
-       summary "$1"
+       new_head=$(git-rev-parse --verify "$1^0") &&
+       git-read-tree -u -m $head "$new_head" &&
+       finish "$new_head" "Fast forward"
        dropsave
        exit 0
        ;;
-1,*)
+1,?*"$LF"?*)
        # We are not doing octopus and not fast forward.  Need a
        # real merge.
        ;;
+1,*)
+       # We are not doing octopus, not fast forward, and have only
+       # one common.  See if it is really trivial.
+       echo "Trying really trivial in-index merge..."
+       git-update-index --refresh 2>/dev/null
+       if git-read-tree --trivial -m -u $common $head "$1" &&
+          result_tree=$(git-write-tree)
+       then
+           echo "Wonderful."
+           result_commit=$(
+               echo "$merge_msg" |
+               git-commit-tree $result_tree -p HEAD -p "$1"
+           ) || exit
+           finish "$result_commit" "In-index merge"
+           dropsave
+           exit 0
+       fi
+       echo "Nope."
+       ;;
 *)
        # An octopus.  If we can reach all the remote we are up to date.
        up_to_date=t
@@ -149,12 +180,7 @@ esac
 # we use, it would operate on the index, possibly affecting the
 # working tree, and when resolved cleanly, have the desired tree
 # in the index -- this means that the index must be in sync with
-# the $head commit.
-files=$(git-diff-index --cached --name-only $head) || exit
-if [ "$files" ]; then
-   echo >&2 "Dirty index: cannot merge (dirty: $files)"
-   exit 1
-fi
+# the $head commit.  The strategies are responsible to ensure this.
 
 case "$use_strategies" in
 ?*' '?*)
@@ -218,10 +244,8 @@ then
     do
         parents="$parents -p $remote"
     done
-    result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents)
-    echo "Committed merge $result_commit, made by $wt_strategy."
-    echo $result_commit >"$GIT_DIR/HEAD"
-    summary $result_commit
+    result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
+    finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
     dropsave
     exit 0
 fi