rev-list.c: fix non-grammatical comments.
[gitweb.git] / git-merge.sh
index a784e0f2cc5935a68795cb9f5ecf1b13716477f6..4609fe54d52843f42d2c1d18a9dc2ff235b5c7ce 100755 (executable)
@@ -3,29 +3,55 @@
 # Copyright (c) 2005 Junio C Hamano
 #
 
-. git-sh-setup || die "Not a git archive"
+
+USAGE='[-n] [--no-commit] [-s <strategy>]... <merge-message> <head> <remote>+'
+. git-sh-setup
 
 LF='
 '
 
-usage () {
-    die "git-merge [-n] [-s <strategy>]... <merge-message> <head> <remote>+"
-}
+all_strategies='recursive octopus resolve stupid ours'
+default_strategies='recursive'
+use_strategies=
+if test "@@NO_PYTHON@@"; then
+       all_strategies='resolve octopus stupid ours'
+       default_strategies='resolve'
+fi
 
-# all_strategies='resolve fredrik stupid octopus'
+dropsave() {
+       rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
+                "$GIT_DIR/MERGE_SAVE" || exit 1
+}
 
-all_strategies='fredrik octopus resolve stupid'
-default_strategies='resolve octopus'
-use_strategies=
+savestate() {
+       # Stash away any local modifications.
+       git-diff-index -z --name-only $head |
+       cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
+}
 
-dropheads() {
-       rm -f -- "$GIT_DIR/MERGE_HEAD" || exit 1
+restorestate() {
+        if test -f "$GIT_DIR/MERGE_SAVE"
+       then
+               git reset --hard $head
+               cpio -iuv <"$GIT_DIR/MERGE_SAVE"
+               git-update-index --refresh >/dev/null
+       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" "$1" |
                git-apply --stat --summary
                ;;
        esac
@@ -37,13 +63,15 @@ do
        -n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
                --no-summa|--no-summar|--no-summary)
                no_summary=t ;;
+       --no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
+               no_commit=t ;;
        -s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
                --strateg=*|--strategy=*|\
        -s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
                case "$#,$1" in
                *,*=*)
                        strategy=`expr "$1" : '-[^=]*=\(.*\)'` ;;
-               0,*)
+               1,*)
                        usage ;;
                *)
                        strategy="$2"
@@ -62,59 +90,86 @@ do
        shift
 done
 
-case "$use_strategies" in
-'')
-       use_strategies=$default_strategies
-       ;;
-esac
 test "$#" -le 2 && usage ;# we need at least two heads.
 
 merge_msg="$1"
 shift
+head_arg="$1"
 head=$(git-rev-parse --verify "$1"^0) || usage
 shift
 
 # All the rest are remote heads
+remoteheads=
 for remote
 do
-       git-rev-parse --verify "$remote"^0 >/dev/null ||
+       remotehead=$(git-rev-parse --verify "$remote"^0) ||
            die "$remote - not something we can merge"
+       remoteheads="${remoteheads}$remotehead "
 done
+set x $remoteheads ; shift
 
-common=$(git-show-branch --merge-base $head "$@")
+case "$#" in
+1)
+       common=$(git-merge-base --all $head "$@")
+       ;;
+*)
+       common=$(git-show-branch --merge-base $head "$@")
+       ;;
+esac
 echo "$head" >"$GIT_DIR/ORIG_HEAD"
 
-case "$#,$common" in
-*,'')
-       die "Unable to find common commit between $head and $*"
+case "$#,$common,$no_commit" in
+*,'',*)
+       # No common ancestors found. We need a real merge.
        ;;
-1,"$1")
+1,"$1",*)
        # If head can reach all the merge then we are up to date.
        # but first the most common case of merging one remote
-       echo "Already up-to-date. Yeeah!"
-       dropheads
+       echo "Already up-to-date."
+       dropsave
        exit 0
        ;;
-1,"$head")
+1,"$head",*)
        # 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 "$1"
-       dropheads
+       new_head=$(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.
+       git var GIT_COMMITTER_IDENT >/dev/null || exit
+
+       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
        for remote
        do
-               common_one=$(git-merge-base $head $remote)
+               common_one=$(git-merge-base --all $head $remote)
                if test "$common_one" != "$remote"
                then
                        up_to_date=f
@@ -124,35 +179,74 @@ case "$#,$common" in
        if test "$up_to_date" = t
        then
                echo "Already up-to-date. Yeeah!"
-               dropheads
+               dropsave
                exit 0
        fi
        ;;
 esac
 
-# At this point we need a real merge.  Require that the tree matches
-# exactly our head.
+# We are going to make a new commit.
+git var GIT_COMMITTER_IDENT >/dev/null || exit
 
-git-update-index --refresh &&
-test '' = "`git-diff-index --cached --name-only $head`" || {
-       die "Need real merge but the working tree has local changes."
-}
+case "$use_strategies" in
+'')
+       case "$#" in
+       1)
+               use_strategies="$default_strategies" ;;
+       *)
+               use_strategies=octopus ;;
+       esac            
+       ;;
+esac
+
+# At this point, we need a real merge.  No matter what strategy
+# 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 $head commit.  The strategies are responsible to ensure this.
+
+case "$use_strategies" in
+?*' '?*)
+    # Stash away the local changes so that we can try more than one.
+    savestate
+    single_strategy=no
+    ;;
+*)
+    rm -f "$GIT_DIR/MERGE_SAVE"
+    single_strategy=yes
+    ;;
+esac
 
 result_tree= best_cnt=-1 best_strategy= wt_strategy=
+merge_was_ok=
 for strategy in $use_strategies
 do
     test "$wt_strategy" = '' || {
        echo "Rewinding the tree to pristine..."
-       git reset --hard $head
+       restorestate
     }
-    echo "Trying merge strategy $strategy..."
+    case "$single_strategy" in
+    no)
+       echo "Trying merge strategy $strategy..."
+       ;;
+    esac
+
+    # Remember which strategy left the state in the working tree
     wt_strategy=$strategy
-    git-merge-$strategy $common -- $head "$@" || {
+
+    git-merge-$strategy $common -- "$head_arg" "$@"
+    exit=$?
+    if test "$no_commit" = t && test "$exit" = 0
+    then
+        merge_was_ok=t
+       exit=1 ;# pretend it left conflicts.
+    fi
+
+    test "$exit" = 0 || {
 
        # The backend exits with 1 when conflicts are left to be resolved,
        # with 2 when it does not handle the given merge at all.
 
-       exit=$?
        if test "$exit" -eq 1
        then
            cnt=`{
@@ -181,32 +275,52 @@ 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 $result_commit
-    dropheads
+    result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
+    finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
+    dropsave
     exit 0
 fi
 
 # Pick the result from the best strategy and have the user fix it up.
 case "$best_strategy" in
 '')
-       git reset --hard $head
-       die "No merge strategy handled the merge."
+       restorestate
+       echo >&2 "No merge strategy handled the merge."
+       exit 2
        ;;
 "$wt_strategy")
        # We already have its result in the working tree.
        ;;
 *)
        echo "Rewinding the tree to pristine..."
-       git reset --hard $head
+       restorestate
        echo "Using the $best_strategy to prepare resolving by hand."
-       git-merge-$best_strategy $common -- $head "$@"
+       git-merge-$best_strategy $common -- "$head_arg" "$@"
        ;;
 esac
 for remote
 do
        echo $remote
 done >"$GIT_DIR/MERGE_HEAD"
-die "Automatic merge failed; fix up by hand"
+echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
+
+if test "$merge_was_ok" = t
+then
+       echo >&2 \
+       "Automatic merge went well; stopped before committing as requested"
+       exit 0
+else
+       {
+           echo '
+Conflicts:
+'
+               git ls-files --unmerged |
+               sed -e 's/^[^   ]*      /       /' |
+               uniq
+       } >>"$GIT_DIR/MERGE_MSG"
+       if test -d "$GIT_DIR/rr-cache"
+       then
+               git-rerere
+       fi
+       die "Automatic merge failed; fix up by hand"
+fi