The git-cherry-pick --allow-empty command by default only preserves empty
commits that were originally empty, i.e only those commits for which
<commit>^{tree} and <commit>^^{tree} are equal. By default commits which are
non-empty, but were made empty by the inclusion of a prior commit on the current
history are filtered out. This option allows us to override that behavior and
include redundant commits as empty commits in the change history.
Signed-off-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
---
Documentation/git-cherry-pick.txt | 12 ++++-
builtin/revert.c | 8 +++-
sequencer.c | 97 ++++++++++++++++++++++++++++++++-----
sequencer.h | 1 +
4 files changed, 103 insertions(+), 15 deletions(-)
diff --git a/Documentation/git-cherry-pick.txt b/Documentation/git-cherry-pick.txt
index 730237a..0c004e9 100644
--- a/Documentation/git-cherry-pick.txt
+++ b/Documentation/git-cherry-pick.txt
@@ -110,7 +110,17 @@ effect to your index in a row.
behavior, allowing empty commits to be preserved automatically
in a cherry-pick. Note that when "--ff" is in effect, empty
commits that meet the "fast-forward" requirement will be kept
- even without this option.
+ even without this option. Note also, that use of this option only
+ keeps commits that were initially empty (i.e. the commit recorded the
+ same tree as its parent). Commits which are made empty due to a
+ previous commit are ignored. To force the inclusion of those commits
+ use `--keep-redundant-commits`.
+
+--keep-redundant-commits::
+ If a commit being cherry picked duplicates a commit already in the
+ current history, it will result in an empty changeset. By default these
+ redundant commits are ignored. This option overrides that behavior and
+ creates an empty commit object. Implies `--allow-empty`.
--strategy=<strategy>::
Use the given merge strategy. Should only be used once.
diff --git a/builtin/revert.c b/builtin/revert.c
index 06b00e6..f135502 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -115,13 +115,15 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
OPT_END(),
OPT_END(),
OPT_END(),
+ OPT_END(),
};
if (opts->action == REPLAY_PICK) {
struct option cp_extra[] = {
OPT_BOOLEAN('x', NULL, &opts->record_origin, "append commit name"),
OPT_BOOLEAN(0, "ff", &opts->allow_ff, "allow fast-forward"),
- OPT_BOOLEAN(0, "allow-empty", &opts->allow_empty, "preserve empty commits"),
+ OPT_BOOLEAN(0, "allow-empty", &opts->allow_empty, "preserve initially empty commits"),
+ OPT_BOOLEAN(0, "keep-redundant-commits", &opts->keep_redundant_commits, "keep redundant, empty commits"),
OPT_END(),
};
if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
@@ -139,6 +141,10 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
"--abort", rollback,
NULL);
+ /* keep_if_made_empty implies allow_empty */
+ if (opts->keep_redundant_commits)
+ opts->allow_empty = 1;
+
/* Set the subcommand */
if (remove_state)
opts->subcommand = REPLAY_REMOVE_STATE;
diff --git a/sequencer.c b/sequencer.c
index 71929ba..acc9c6d 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -13,6 +13,7 @@
#include "rerere.h"
#include "merge-recursive.h"
#include "refs.h"
+#include "argv-array.h"
#define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
@@ -251,6 +252,30 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
return !clean;
}
+static int is_index_unchanged()
+{
+ unsigned char head_sha1[20];
+ struct commit *head_commit;
+
+ if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
+ return error(_("Could not resolve HEAD commit\n"));
+
+ head_commit = lookup_commit(head_sha1);
+ if (!head_commit || parse_commit(head_commit))
+ return error(_("could not parse commit %s\n"),
+ sha1_to_hex(head_commit->object.sha1));
+
+ if (!active_cache_tree)
+ active_cache_tree = cache_tree();
+
+ if (!cache_tree_fully_valid(active_cache_tree))
+ if (cache_tree_update(active_cache_tree, active_cache,
+ active_nr, 0))
+ return error(_("Unable to update cache tree\n"));
+
+ return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
+}
+
/*
* If we are cherry-pick, and if the merge did not result in
* hand-editing, we will hit this commit and inherit the original
@@ -258,26 +283,67 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
* If we are revert, or if our cherry-pick results in a hand merge,
* we had better say that the current user is responsible for that.
*/
-static int run_git_commit(const char *defmsg, struct replay_opts *opts)
+static int run_git_commit(const char *defmsg, struct replay_opts *opts, int empty)
{
- /* 7 is max possible length of our args array including NULL */
- const char *args[7];
- int i = 0;
+ struct argv_array array;
+ int rc;
+ int index_unchanged = is_index_unchanged();
+
+ /*
+ * if index_unchanged is < 0, then we encountered an error
+ * trying to parse HEAD or the active_cache_tree, so bail out
+ */
+ if (index_unchanged < 0)
+ return index_unchanged;
+
+ if (!empty && !opts->keep_redundant_commits && index_unchanged)
+ /*
+ * The head tree and the index match
+ * meaning the commit is empty. Since it wasn't created
+ * empty (based on the previous test), we can conclude
+ * the commit has been made redundant. Since we don't
+ * want to keep redundant commits, we can just return
+ * here, skipping this commit
+ */
+ return 0;
+
+ argv_array_init(&array);
+ argv_array_push(&array, "commit");
+ argv_array_push(&array, "-n");
- args[i++] = "commit";
- args[i++] = "-n";
if (opts->signoff)
- args[i++] = "-s";
+ argv_array_push(&array, "-s");
if (!opts->edit) {
- args[i++] = "-F";
- args[i++] = defmsg;
+ argv_array_push(&array, "-F");
+ argv_array_push(&array, defmsg);
}
+
if (opts->allow_empty)
- args[i++] = "--allow-empty";
+ argv_array_push(&array, "--allow-empty");
+
+ rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
+ argv_array_clear(&array);
+ return rc;
+}
- args[i] = NULL;
+static int is_original_commit_empty(struct commit *commit)
+{
+ const unsigned char *ptree_sha1;
- return run_command_v_opt(args, RUN_GIT_CMD);
+ if (parse_commit(commit))
+ return error(_("Could not parse commit %s\n"),
+ sha1_to_hex(commit->object.sha1));
+ if (commit->parents) {
+ struct commit *parent = commit->parents->item;
+ if (parse_commit(parent))
+ return error(_("Could not parse parent commit %s\n"),
+ sha1_to_hex(parent->object.sha1));
+ ptree_sha1 = parent->tree->object.sha1;
+ } else {
+ ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
+ }
+
+ return !hashcmp(ptree_sha1, commit->tree->object.sha1);
}
static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
@@ -289,6 +355,7 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
char *defmsg = NULL;
struct strbuf msgbuf = STRBUF_INIT;
int res;
+ int empty_commit;
if (opts->no_commit) {
/*
@@ -414,6 +481,10 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
free_commit_list(remotes);
}
+ empty_commit = is_original_commit_empty(commit);
+ if (empty_commit < 0)
+ return empty_commit;
+
/*
* If the merge was clean or if it failed due to conflict, we write
* CHERRY_PICK_HEAD for the subsequent invocation of commit to use.
@@ -435,7 +506,7 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
rerere(opts->allow_rerere_auto);
} else {
if (!opts->no_commit)
- res = run_git_commit(defmsg, opts);
+ res = run_git_commit(defmsg, opts, empty_commit);
}
free_message(&msg);
diff --git a/sequencer.h b/sequencer.h
index e2cd725..aa5f17c 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -30,6 +30,7 @@ struct replay_opts {
int allow_ff;
int allow_rerere_auto;
int allow_empty;
+ int keep_redundant_commits;
int mainline;
--
1.7.7.6
--
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