Handle core.symlinks=false case in merge-recursive.

If the file system does not support symbolic links (core.symlinks=false),
merge-recursive must write the merged symbolic link text into a regular
file.

While we are here, fix a tiny memory leak in the if-branch that writes
real symbolic links.

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
Signed-off-by: Junio C Hamano <junkio@cox.net>

merge-recursive.c

@@ -570,7 +570,7 @@ static void update_file_flags(const unsigned char *sha,
 		if (type != OBJ_BLOB)
 			die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 
-		if (S_ISREG(mode)) {
+		if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 			int fd;
 			if (mkdir_p(path, 0777))
 				die("failed to create path %s: %s", path, strerror(errno));
@@ -591,6 +591,7 @@ static void update_file_flags(const unsigned char *sha,
 			mkdir_p(path, 0777);
 			unlink(path);
 			symlink(lnk, path);
+			free(lnk);
 		} else
 			die("do not know what to do with %06o %s '%s'",
 			    mode, sha1_to_hex(sha), path);

t/t6025-merge-symlinks.sh

@@ -0,0 +1,62 @@
+#!/bin/sh
+#
+# Copyright (c) 2007 Johannes Sixt
+#
+
+test_description='merging symlinks on filesystem w/o symlink support.
+
+This tests that git-merge-recursive writes merge results as plain files
+if core.symlinks is false.'
+
+. ./test-lib.sh
+
+test_expect_success \
+'setup' '
+git-config core.symlinks false &&
+> file &&
+git-add file &&
+git-commit -m initial &&
+git-branch b-symlink &&
+git-branch b-file &&
+l=$(echo -n file | git-hash-object -t blob -w --stdin) &&
+echo "120000 $l	symlink" | git-update-index --index-info &&
+git-commit -m master &&
+git-checkout b-symlink &&
+l=$(echo -n file-different | git-hash-object -t blob -w --stdin) &&
+echo "120000 $l	symlink" | git-update-index --index-info &&
+git-commit -m b-symlink &&
+git-checkout b-file &&
+echo plain-file > symlink &&
+git-add symlink &&
+git-commit -m b-file'
+
+test_expect_failure \
+'merge master into b-symlink, which has a different symbolic link' '
+! git-checkout b-symlink ||
+git-merge master'
+
+test_expect_success \
+'the merge result must be a file' '
+test -f symlink'
+
+test_expect_failure \
+'merge master into b-file, which has a file instead of a symbolic link' '
+! (git-reset --hard &&
+git-checkout b-file) ||
+git-merge master'
+
+test_expect_success \
+'the merge result must be a file' '
+test -f symlink'
+
+test_expect_failure \
+'merge b-file, which has a file instead of a symbolic link, into master' '
+! (git-reset --hard &&
+git-checkout master) ||
+git-merge b-file'
+
+test_expect_success \
+'the merge result must be a file' '
+test -f symlink'
+
+test_done