[PATCH v3 3/4] reset: add option "--merge-safe" to "git reset"
From: Christian Couder <hidden>
Date: 2016-06-15 22:47:25
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: Stephan Beyer <redacted>
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 [off-list ref]
Mentored-by: Christian Couder [off-list ref]
Signed-off-by: Stephan Beyer <redacted>
Signed-off-by: Christian Couder <redacted>
---
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