From: Stephan Beyer <s-beyer@xxxxxxx>
This option is nearly like "--merge" except that it is
safer.
The table below shows what happens when running
"git reset --option target" to reset the HEAD to another
commit (as a special case "target" could be the same as
HEAD) in the cases where "--merge" and "--merge-safe"
(abreviated --m-s) behave differently.
working index HEAD target working index HEAD
B B A A --m-s B A A
--merge A A A
B B A C --m-s (disallowed)
--merge C C C
In this table, A, B and C are some different states of
a file. For example the first line of the table means
that if a file is in state B in the working tree and
the index, and in a different state A in HEAD and in
the target, then "git reset --merge-safe target" will
put the file in state B in the working tree and in
state A in the index and HEAD.
So as can be seen in the table, "--merge" discards changes
in the index, while "--merge-safe" does not.
A following patch will add some test cases for
"--merge-safe", where the differences between "--merge"
and "--merge-safe" can also be seen.
The "--merge-safe" option is implemented by doing a 2 way
merge between HEAD and the reset target, and if this
succeeds by doing a mixed reset to the target.
The code comes from the sequencer GSoC project:
git://repo.or.cz/git/sbeyer.git
(at commit 5a78908b70ceb5a4ea9fd4b82f07ceba1f019079)
But in the sequencer project the "reset" flag was set
in the "struct unpack_trees_options" passed to
"unpack_trees()". With this flag the changes in the
working tree were discarded if the file was different
between HEAD and the reset target.
Mentored-by: Daniel Barkalow <barkalow@xxxxxxxxxxxx>
Mentored-by: Christian Couder <chriscool@xxxxxxxxxxxxx>
Signed-off-by: Stephan Beyer <s-beyer@xxxxxxx>
Signed-off-by: Christian Couder <chriscool@xxxxxxxxxxxxx>
---
builtin-reset.c | 30 +++++++++++++++++++++++++-----
1 files changed, 25 insertions(+), 5 deletions(-)
diff --git a/builtin-reset.c b/builtin-reset.c
index ddb81f3..78d42e6 100644
--- a/builtin-reset.c
+++ b/builtin-reset.c
@@ -22,13 +22,15 @@
#include "cache-tree.h"
static const char * const git_reset_usage[] = {
- "git reset [--mixed | --soft | --hard | --merge] [-q] [<commit>]",
+ "git reset [--mixed | --soft | --hard | --merge | --merge-safe] [-q] [<commit>]",
"git reset [--mixed] <commit> [--] <paths>...",
NULL
};
-enum reset_type { MIXED, SOFT, HARD, MERGE, NONE };
-static const char *reset_type_names[] = { "mixed", "soft", "hard", "merge", NULL };
+enum reset_type { MIXED, SOFT, HARD, MERGE, MERGE_SAFE, NONE };
+static const char *reset_type_names[] = {
+ "mixed", "soft", "hard", "merge", "merge_safe", NULL
+};
static char *args_to_str(const char **argv)
{
@@ -81,6 +83,7 @@ static int reset_index_file(const unsigned char *sha1, int reset_type, int quiet
if (!quiet)
opts.verbose_update = 1;
switch (reset_type) {
+ case MERGE_SAFE:
case MERGE:
opts.update = 1;
break;
@@ -95,6 +98,16 @@ static int reset_index_file(const unsigned char *sha1, int reset_type, int quiet
read_cache_unmerged();
+ if (reset_type == MERGE_SAFE) {
+ unsigned char *head_sha1;
+ if (get_sha1("HEAD", head_sha1))
+ return error("You do not have a valid HEAD.");
+ if (parse_and_init_tree_desc(head_sha1, desc))
+ return error("Failed to find tree of HEAD.");
+ nr++;
+ opts.fn = twoway_merge;
+ }
+
if (parse_and_init_tree_desc(sha1, desc + nr - 1))
return error("Failed to find tree of %s.", sha1_to_hex(sha1));
if (unpack_trees(nr, desc, &opts))
@@ -238,6 +251,9 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
"reset HEAD, index and working tree", HARD),
OPT_SET_INT(0, "merge", &reset_type,
"reset HEAD, index and working tree", MERGE),
+ OPT_SET_INT(0, "merge-safe", &reset_type,
+ "reset HEAD, index and working tree",
+ MERGE_SAFE),
OPT_BOOLEAN('q', NULL, &quiet,
"disable showing new HEAD in hard reset and progress message"),
OPT_BOOLEAN('p', "patch", &patch_mode, "select hunks interactively"),
@@ -324,9 +340,13 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
if (reset_type == SOFT) {
if (is_merge() || read_cache() < 0 || unmerged_cache())
die("Cannot do a soft reset in the middle of a merge.");
+ } else {
+ int err = reset_index_file(sha1, reset_type, quiet);
+ if (reset_type == MERGE_SAFE)
+ err = err || reset_index_file(sha1, MIXED, quiet);
+ if (err)
+ die("Could not reset index file to revision '%s'.", rev);
}
- else if (reset_index_file(sha1, reset_type, quiet))
- die("Could not reset index file to revision '%s'.", rev);
/* Any resets update HEAD to the head being switched to,
* saving the previous head in ORIG_HEAD before. */
--
1.6.5.rc0.150.g38fe6
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