[PATCH v6 4/4] reset: use "unpack_trees()" directly instead of "git read-tree"

From

Christian Couder <chriscool@tuxfamily.org>

Date

Dec 30, 2009, 05:54 UTC

Message-ID

<20091230055448.4475.64716.chriscool@tuxfamily.org>

In-Reply-To

<20091230055008.4475.95755.chriscool@tuxfamily.org>

From: Stephan Beyer <s-beyer@gmx.net>

"
     - if the index has unmerged entries, "--merge" will currently
       simply refuse to reset ("you need to resolve your current index
       first"). You'll need to use "--hard" or similar in this case.

       This is sad, because normally a unmerged index means that the
       working tree file should have matched the source tree, so the
       correct action is likely to make --merge reset such a path to
       the target (like --hard), regardless of dirty state in-tree or
       in-index. But that's not how read-tree has ever worked, so..
"

The code comes from the sequencer GSoC project:

git://repo.or.cz/git/sbeyer.git

(at commit 5a78908b70ceb5a4ea9fd4b82f07ceba1f019079)

Mentored-by: Daniel Barkalow <barkalow@iabervon.org>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
---
 Documentation/git-reset.txt |    2 +-
 builtin-reset.c             |   41 ++++++++++++++++++++++++++++++-----------
 t/t7110-reset-merge.sh      |   12 +++++++-----
 3 files changed, 38 insertions(+), 17 deletions(-)

diff --git a/Documentation/git-reset.txt b/Documentation/git-reset.txt
index c9044c9..b40999f 100644
--- a/Documentation/git-reset.txt
+++ b/Documentation/git-reset.txt
@@ -122,7 +122,7 @@ entries:
        X       U     A    B     --soft  (disallowed)
                                 --mixed  X       B     B
                                 --hard   B       B     B
-                                --merge (disallowed)
+                                --merge  X       B     B
 
       working index HEAD target         working index HEAD
       ----------------------------------------------------
diff --git a/builtin-reset.c b/builtin-reset.c
index 3180c2b..2c880a7 100644
--- a/builtin-reset.c
+++ b/builtin-reset.c
@@ -18,6 +18,8 @@
 #include "tree.h"
 #include "branch.h"
 #include "parse-options.h"
+#include "unpack-trees.h"
+#include "cache-tree.h"
 
 static const char * const git_reset_usage[] = {
 	"git reset [--mixed | --soft | --hard | --merge] [-q] [<commit>]",
@@ -54,27 +56,44 @@ static inline int is_merge(void)
 
 static int reset_index_file(const unsigned char *sha1, int reset_type, int quiet)
 {
-	int i = 0;
-	const char *args[6];
+	int nr = 1;
+	int newfd;
+	struct tree_desc desc[2];
+	struct unpack_trees_options opts;
+	struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 
-	args[i++] = "read-tree";
+	memset(&opts, 0, sizeof(opts));
+	opts.head_idx = 1;
+	opts.src_index = &the_index;
+	opts.dst_index = &the_index;
+	opts.fn = oneway_merge;
+	opts.merge = 1;
 	if (!quiet)
-		args[i++] = "-v";
+		opts.verbose_update = 1;
 	switch (reset_type) {
 	case MERGE:
-		args[i++] = "-u";
-		args[i++] = "-m";
+		opts.update = 1;
 		break;
 	case HARD:
-		args[i++] = "-u";
+		opts.update = 1;
 		/* fallthrough */
 	default:
-		args[i++] = "--reset";
+		opts.reset = 1;
 	}
-	args[i++] = sha1_to_hex(sha1);
-	args[i] = NULL;
 
-	return run_command_v_opt(args, RUN_GIT_CMD);
+	newfd = hold_locked_index(lock, 1);
+
+	read_cache_unmerged();
+
+	if (!fill_tree_descriptor(desc + nr - 1, sha1))
+		return error("Failed to find tree of %s.", sha1_to_hex(sha1));
+	if (unpack_trees(nr, desc, &opts))
+		return -1;
+	if (write_cache(newfd, active_cache, active_nr) ||
+	    commit_locked_index(lock))
+		return error("Could not write new index file.");
+
+	return 0;
 }
 
 static void print_new_head_line(struct commit *commit)
diff --git a/t/t7110-reset-merge.sh b/t/t7110-reset-merge.sh
index 4c46083..ff2875c 100755
--- a/t/t7110-reset-merge.sh
+++ b/t/t7110-reset-merge.sh
@@ -135,12 +135,14 @@ test_expect_success 'setup 2 different branches' '
 #
 #           working index HEAD target         working index HEAD
 #           ----------------------------------------------------
-# file1:     X       U     B    C     --merge  (disallowed)
-test_expect_success '"reset --merge HEAD^" fails with pending merge' '
+# file1:     X       U     B    C     --merge  X       C     C
+test_expect_success '"reset --merge HEAD^" is ok with pending merge' '
     test_must_fail git merge branch1 &&
-    test_must_fail git reset --merge HEAD^ &&
-    test "$(git rev-parse HEAD)" = "$(git rev-parse third)" &&
-    test -n "$(git diff --cached)"
+    cat file1 >orig_file1 &&
+    git reset --merge HEAD^ &&
+    test "$(git rev-parse HEAD)" = "$(git rev-parse second)" &&
+    test -z "$(git diff --cached)" &&
+    test_cmp file1 orig_file1
 '
 
 # The next test will test the following:

-- 
1.6.6.rc2.5.g49666