[PATCH] make file merging respect permissions

1) permissions aren't respected in the merge script (primarily because
they're never passed in to it in the first place).  Fix that and also
check for permission conflicts in the merge

2) the delete of a file in both branches may indeed be just that, but it
could also be the indicator of a rename conflict (file moved to
different locations in both branches), so error out and ask the
committer for guidance.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

git-merge-one-file-script

@@ -20,23 +20,45 @@ mkdir -p "$dir"
 
 case "${1:-.}${2:-.}${3:-.}" in
 #
-# deleted in both, or deleted in one and unchanged in the other
+# deleted in both
+#
+"$1..")
+	echo "ERROR: $4 is removed in both branches"
+	echo "ERROR: This is a potential rename conflict"
+	exit 1;;
+#
+# deleted in one and unchanged in the other
 #
 "$1.." | "$1.$1" | "$1$1.")
 	rm -f -- "$4"
+	echo "Removing $4"
 	update-cache --remove -- "$4"
 	exit 0
 	;;
 
 #
-# added in one, or added identically in both
+# added in one
 #
-".$2." | "..$3" | ".$2$2")
-	mv $(unpack-file "${2:-$3}") $4
+".$2." | "..$3" )
+	echo "Adding $4 with perm $6$7"
+	mv $(unpack-file "$2$3") $4
+	chmod "$6$7" $4
 	update-cache --add -- $4
 	exit 0
 	;;
-
+#
+# Added in both (check for same permissions)
+#
+".$2$2")
+	if [ "$6" != "$7" ]; then
+		echo "ERROR: File $4 added in both branches, permissions conflict $6->$7"
+		exit 1
+	fi
+	echo "Adding $4 with perm $6"
+	mv $(unpack-file "$2") $4
+	chmod "$6" $4
+	update-cache --add -- $4
+	exit 0;;
 #
 # Modified in both, but differently ;(
 #
@@ -46,11 +68,20 @@ case "${1:-.}${2:-.}${3:-.}" in
 	src1=$(unpack-file $2)
 	src2=$(unpack-file $3)
 	merge "$src2" "$orig" "$src1"
-	if [ $? -ne 0 ]; then
-		echo Leaving conflict merge in $src2
+	ret=$?
+	if [ "$6" != "$7" ]; then
+		echo "ERROR: Permissions $5->$6->$7 don't match merging $src2"
+		if [ $ret -ne 0 ]; then
+			echo "ERROR: Leaving conflict merge in $src2"
+		fi
+		exit 1
+	fi
+	chmod -- "$6" "$src2"
+	if [ $ret -ne 0 ]; then
+		echo "ERROR: Leaving conflict merge in $src2"
 		exit 1
 	fi
-	cp "$src2" "$4" && update-cache --add -- "$4" && exit 0
+	cp -- "$src2" "$4" && chmod -- "$6" "$4" &&  update-cache --add -- "$4" && exit 0
 	;;
 
 *)

merge-cache.c

@@ -4,7 +4,7 @@
 #include "cache.h"
 
 static const char *pgm = NULL;
-static const char *arguments[5];
+static const char *arguments[8];
 
 static void run_program(void)
 {
@@ -18,6 +18,9 @@ static void run_program(void)
 			    arguments[2],
 			    arguments[3],
 			    arguments[4],
+			    arguments[5],
+			    arguments[6],
+			    arguments[7],
 			    NULL);
 		die("unable to execute '%s'", pgm);
 	}
@@ -36,17 +39,23 @@ static int merge_entry(int pos, const char *path)
 	arguments[2] = "";
 	arguments[3] = "";
 	arguments[4] = path;
+	arguments[5] = "";
+	arguments[6] = "";
+	arguments[7] = "";
 	found = 0;
 	do {
 		static char hexbuf[4][60];
+		static char ownbuf[4][60];
 		struct cache_entry *ce = active_cache[pos];
 		int stage = ce_stage(ce);
 
 		if (strcmp(ce->name, path))
 			break;
 		found++;
 		strcpy(hexbuf[stage], sha1_to_hex(ce->sha1));
+		sprintf(ownbuf[stage], "%o", ntohl(ce->ce_mode) & (~S_IFMT));
 		arguments[stage] = hexbuf[stage];
+		arguments[stage + 4] = ownbuf[stage];
 	} while (++pos < active_nr);
 	if (!found)
 		die("merge-cache: %s not in the cache", path);