git-fetch: exit with non-zero status when fast-forward check fails

diff --git a/git-merge-one-file.sh b/git-merge-one-file.sh
index 5419e598c52eec1b8e40b4179b0bd6ebae40b682..c49e4c65af606496c7e65b5147e36fee105d9ae7 100755 (executable)
--- a/git-merge-one-file.sh
+++ b/git-merge-one-file.sh
@@ -8,7 +8,7 @@
 #   $2 - file in branch1 SHA1 (or empty)
 #   $3 - file in branch2 SHA1 (or empty)
 #   $4 - pathname in repository
-#   $5 - orignal file mode (or empty)
+#   $5 - original file mode (or empty)
 #   $6 - file in branch1 mode (or empty)
 #   $7 - file in branch2 mode (or empty)
 #
@@ -23,9 +23,16 @@ case "${1:-.}${2:-.}${3:-.}" in
 "$1.." | "$1.$1" | "$1$1.")
        if [ "$2" ]; then
                echo "Removing $4"
+       else
+               # read-tree checked that index matches HEAD already,
+               # so we know we do not have this path tracked.
+               # there may be an unrelated working tree file here,
+               # which we should just leave unmolested.
+               exit 0
        fi
        if test -f "$4"; then
-               rm -f -- "$4"
+               rm -f -- "$4" &&
+               rmdir -p "$(expr "z$4" : 'z\(.*\)/')" 2>/dev/null || :
        fi &&
                exec git-update-index --remove -- "$4"
        ;;
@@ -33,14 +40,22 @@ case "${1:-.}${2:-.}${3:-.}" in
 #
 # Added in one.
 #
-".$2." | "..$3" )
+".$2.")
+       # the other side did not add and we added so there is nothing
+       # to be done.
+       ;;
+"..$3")
        echo "Adding $4"
+       test -f "$4" || {
+               echo "ERROR: untracked $4 is overwritten by the merge."
+               exit 1
+       }
        git-update-index --add --cacheinfo "$6$7" "$2$3" "$4" &&
                exec git-checkout-index -u -f -- "$4"
        ;;
 
 #
-# Added in both (check for same permissions).
+# Added in both, identically (check for same permissions).
 #
 ".$3$2")
        if [ "$6" != "$7" ]; then
@@ -56,26 +71,57 @@ case "${1:-.}${2:-.}${3:-.}" in
 #
 # Modified in both, but differently.
 #
-"$1$2$3")
-       echo "Auto-merging $4."
-       orig=`git-unpack-file $1`
+"$1$2$3" | ".$2$3")
+
+       case ",$6,$7," in
+       *,120000,*)
+               echo "ERROR: $4: Not merging symbolic link changes."
+               exit 1
+               ;;
+       esac
+
        src2=`git-unpack-file $3`
+       case "$1" in
+       '')
+               echo "Added $4 in both, but differently."
+               # This extracts OUR file in $orig, and uses git-apply to
+               # remove lines that are unique to ours.
+               orig=`git-unpack-file $2`
+               sz0=`wc -c <"$orig"`
+               diff -u -La/$orig -Lb/$orig $orig $src2 | git-apply --no-add 
+               sz1=`wc -c <"$orig"`
 
-       # We reset the index to the first branch, making
-       # git-diff-file useful
-       git-update-index --add --cacheinfo "$6" "$2" "$4"
-               git-checkout-index -u -f -- "$4" &&
-               merge "$4" "$orig" "$src2"
+               # If we do not have enough common material, it is not
+               # worth trying two-file merge using common subsections.
+               expr "$sz0" \< "$sz1" \* 2 >/dev/null || : >$orig
+               ;;
+       *)
+               echo "Auto-merging $4"
+               orig=`git-unpack-file $1`
+               ;;
+       esac
+
+       # Be careful for funny filename such as "-L" in "$4", which
+       # would confuse "merge" greatly.
+       src1=`git-unpack-file $2`
+       merge "$src1" "$orig" "$src2"
        ret=$?
-       rm -f -- "$orig" "$src2"
+
+       # Create the working tree file, using "our tree" version from the
+       # index, and then store the result of the merge.
+       git-checkout-index -f --stage=2 -- "$4" && cat "$src1" >"$4"
+       rm -f -- "$orig" "$src1" "$src2"
 
        if [ "$6" != "$7" ]; then
                echo "ERROR: Permissions conflict: $5->$6,$7."
                ret=1
        fi
+       if [ "$1" = '' ]; then
+               ret=1
+       fi
 
        if [ $ret -ne 0 ]; then
-               echo "ERROR: Merge conflict in $4."
+               echo "ERROR: Merge conflict in $4"
                exit 1
        fi
        exec git-update-index -- "$4"