Get rid of the dependency on RCS' merge program

Now that we have git-merge-file, an RCS merge lookalike, we no longer
need it. So long, merge, and thanks for all the fish!

Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>

8 files changed, 20 insertions, 89 deletions

diff --git a/.gitignore b/.gitignore
index 7f2cd55088..d706dd92c6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -60,6 +60,7 @@ git-mailsplit
 git-merge
 git-merge-base
 git-merge-index
+git-merge-file
 git-merge-tree
 git-merge-octopus
 git-merge-one-file
diff --git a/Documentation/git-merge-index.txt b/Documentation/git-merge-index.txt
index 6cd0601082..0cf505ea84 100644
--- a/Documentation/git-merge-index.txt
+++ b/Documentation/git-merge-index.txt
@@ -40,8 +40,8 @@ If "git-merge-index" is called with multiple <file>s (or -a) then it
 processes them in turn only stopping if merge returns a non-zero exit
 code.
 
-Typically this is run with the a script calling the merge command from
-the RCS package.
+Typically this is run with the a script calling git's imitation of
+the merge command from the RCS package.
 
 A sample script called "git-merge-one-file" is included in the
 distribution.
diff --git a/INSTALL b/INSTALL
index 8f69039fb9..b5dd9f0abb 100644
--- a/INSTALL
+++ b/INSTALL
@@ -82,15 +82,6 @@ Issues of note:
 	  do that even if it wasn't for git.  There's no point in living
 	  in the dark ages any more. 
 
-	- "merge", the standard UNIX three-way merge program.  It usually
-	  comes with the "rcs" package on most Linux distributions, so if
-	  you have a developer install you probably have it already, but a
-	  "graphical user desktop" install might have left it out.
-
-	  You'll only need the merge program if you do development using
-	  git, and if you only use git to track other peoples work you'll
-	  never notice the lack of it. 
-
         - "wish", the Tcl/Tk windowing shell is used in gitk to show the
           history graphically
 
diff --git a/git-cvsserver.perl b/git-cvsserver.perl
index ca519b7e49..55ff83b1a3 100755
--- a/git-cvsserver.perl
+++ b/git-cvsserver.perl
@@ -945,7 +945,7 @@ sub req_update
 
             $log->debug("Temporary directory for merge is $dir");
 
-            my $return = system("merge", $file_local, $file_old, $file_new);
+            my $return = system("git merge-file", $file_local, $file_old, $file_new);
             $return >>= 8;
 
             if ( $return == 0 )
diff --git a/git-rerere.perl b/git-rerere.perl
index d3664ff491..2e8dbbd4ea 100755
--- a/git-rerere.perl
+++ b/git-rerere.perl
@@ -154,7 +154,7 @@ sub find_conflict {
 sub merge {
 	my ($name, $path) = @_;
 	record_preimage($path, "$rr_dir/$name/thisimage");
-	unless (system('merge', map { "$rr_dir/$name/${_}image" }
+	unless (system('git merge-file', map { "$rr_dir/$name/${_}image" }
 		       qw(this pre post))) {
 		my $in;
 		open $in, "<$rr_dir/$name/thisimage" or
diff --git a/git.spec.in b/git.spec.in
index f2374b7331..fb95e37594 100644
--- a/git.spec.in
+++ b/git.spec.in
@@ -24,7 +24,7 @@ This is a dummy package which brings in all subpackages.
 %package core
 Summary:	Core git tools
 Group:		Development/Tools
-Requires:	zlib >= 1.2, rsync, rcs, curl, less, openssh-clients, expat
+Requires:	zlib >= 1.2, rsync, curl, less, openssh-clients, expat
 %description core
 This is a stupid (but extremely fast) directory content manager.  It
 doesn't do a whole lot, but what it _does_ do is track directory
diff --git a/merge-file.c b/merge-file.c
index fc9b148993..69dc1ebbf7 100644
--- a/merge-file.c
+++ b/merge-file.c
@@ -3,52 +3,6 @@
 #include "xdiff-interface.h"
 #include "blob.h"
 
-static void rm_temp_file(const char *filename)
-{
-	unlink(filename);
-	free((void *)filename);
-}
-
-static const char *write_temp_file(mmfile_t *f)
-{
-	int fd;
-	const char *tmp = getenv("TMPDIR");
-	char *filename;
-
-	if (!tmp)
-		tmp = "/tmp";
-	filename = mkpath("%s/%s", tmp, "git-tmp-XXXXXX");
-	fd = mkstemp(filename);
-	if (fd < 0)
-		return NULL;
-	filename = xstrdup(filename);
-	if (f->size != xwrite(fd, f->ptr, f->size)) {
-		rm_temp_file(filename);
-		return NULL;
-	}
-	close(fd);
-	return filename;
-}
-
-static void *read_temp_file(const char *filename, unsigned long *size)
-{
-	struct stat st;
-	char *buf = NULL;
-	int fd = open(filename, O_RDONLY);
-	if (fd < 0)
-		return NULL;
-	if (!fstat(fd, &st)) {
-		*size = st.st_size;
-		buf = xmalloc(st.st_size);
-		if (st.st_size != xread(fd, buf, st.st_size)) {
-			free(buf);
-			buf = NULL;
-		}
-	}
-	close(fd);
-	return buf;
-}
-
 static int fill_mmfile_blob(mmfile_t *f, struct blob *obj)
 {
 	void *buf;
@@ -72,22 +26,19 @@ static void free_mmfile(mmfile_t *f)
 
 static void *three_way_filemerge(mmfile_t *base, mmfile_t *our, mmfile_t *their, unsigned long *size)
 {
-	void *res;
-	const char *t1, *t2, *t3;
-
-	t1 = write_temp_file(base);
-	t2 = write_temp_file(our);
-	t3 = write_temp_file(their);
-	res = NULL;
-	if (t1 && t2 && t3) {
-		int code = run_command("merge", t2, t1, t3, NULL);
-		if (!code || code == -1)
-			res = read_temp_file(t2, size);
-	}
-	rm_temp_file(t1);
-	rm_temp_file(t2);
-	rm_temp_file(t3);
-	return res;
+	mmbuffer_t res;
+	xpparam_t xpp;
+	int merge_status;
+
+	memset(&xpp, 0, sizeof(xpp));
+	merge_status = xdl_merge(base, our, ".our", their, ".their",
+		&xpp, XDL_MERGE_ZEALOUS, &res);
+
+	if (merge_status < 0)
+		return NULL;
+
+	*size = res.size;
+	return res.ptr;
 }
 
 static int common_outf(void *priv_, mmbuffer_t *mb, int nbuf)
diff --git a/t/t0000-basic.sh b/t/t0000-basic.sh
index 81f3bedc90..3260d1d7a7 100755
--- a/t/t0000-basic.sh
+++ b/t/t0000-basic.sh
@@ -19,11 +19,7 @@ modification *should* take notice and update the test vectors here.
 '
 
 ################################################################
-# It appears that people are getting bitten by not installing
-# 'merge' (usually part of RCS package in binary distributions).
-# Check this and error out before running any tests.  Also catch
-# the bogosity of trying to run tests without building while we
-# are at it.
+# It appears that people try to run tests without building...
 
 ../git >/dev/null
 if test $? != 1
@@ -32,14 +28,6 @@ then
 	exit 1
 fi
 
-merge >/dev/null 2>/dev/null
-if test $? = 127
-then
-	echo >&2 'You do not seem to have "merge" installed.
-Please check INSTALL document.'
-	exit 1
-fi
-
 . ./test-lib.sh
 
 ################################################################