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Merge branch 'nh/empty-rebase'

"git rebase" learned to optionally keep commits that do not introduce
any change in the original history.

By Neil Horman
* nh/empty-rebase:
  git-rebase: add keep_empty flag
  git-cherry-pick: Add test to validate new options
  git-cherry-pick: Add keep-redundant-commits option
  git-cherry-pick: add allow-empty option
  • Loading branch information...
2 parents 563b352 + 90e1818 commit 1692579dd3569ebc01187872db91ee2ad93cc962 @gitster gitster committed Apr 30, 2012
@@ -103,6 +103,25 @@ effect to your index in a row.
cherry-pick'ed commit, then a fast forward to this commit will
be performed.
+--allow-empty::
+ By default, cherry-picking an empty commit will fail,
+ indicating that an explicit invocation of `git commit
+ --allow-empty` is required. This option overrides that
+ 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. 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 dropped. 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 become empty. 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.
See the MERGE STRATEGIES section in linkgit:git-merge[1]
@@ -238,6 +238,10 @@ leave out at most one of A and B, in which case it defaults to HEAD.
will be reset to where it was when the rebase operation was
started.
+--keep-empty::
+ Keep the commits that do not change anything from its
+ parents in the result.
+
--skip::
Restart the rebasing process by skipping the current patch.
View
@@ -115,12 +115,16 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
OPT_END(),
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 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))
@@ -138,6 +142,10 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
"--abort", rollback,
NULL);
+ /* implies allow_empty */
+ if (opts->keep_redundant_commits)
+ opts->allow_empty = 1;
+
/* Set the subcommand */
if (remove_state)
opts->subcommand = REPLAY_REMOVE_STATE;
View
@@ -20,11 +20,20 @@ esac
test -n "$rebase_root" && root_flag=--root
-git format-patch -k --stdout --full-index --ignore-if-in-upstream \
- --src-prefix=a/ --dst-prefix=b/ \
- --no-renames $root_flag "$revisions" |
-git am $git_am_opt --rebasing --resolvemsg="$resolvemsg" &&
-move_to_original_branch
+if test -n "$keep_empty"
+then
+ # we have to do this the hard way. git format-patch completely squashes
+ # empty commits and even if it didn't the format doesn't really lend
+ # itself well to recording empty patches. fortunately, cherry-pick
+ # makes this easy
+ git cherry-pick --allow-empty "$revisions"
+else
+ git format-patch -k --stdout --full-index --ignore-if-in-upstream \
+ --src-prefix=a/ --dst-prefix=b/ \
+ --no-renames $root_flag "$revisions" |
+ git am $git_am_opt --rebasing --resolvemsg="$resolvemsg"
+fi && move_to_original_branch
+
ret=$?
test 0 != $ret -a -d "$state_dir" && write_basic_state
exit $ret
View
@@ -167,6 +167,14 @@ has_action () {
sane_grep '^[^#]' "$1" >/dev/null
}
+is_empty_commit() {
+ tree=$(git rev-parse -q --verify "$1"^{tree} 2>/dev/null ||
+ die "$1: not a commit that can be picked")
+ ptree=$(git rev-parse -q --verify "$1"^^{tree} 2>/dev/null ||
+ ptree=4b825dc642cb6eb9a060e54bf8d69288fbee4904)
+ test "$tree" = "$ptree"
+}
+
# Run command with GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, and
# GIT_AUTHOR_DATE exported from the current environment.
do_with_author () {
@@ -191,12 +199,19 @@ git_sequence_editor () {
pick_one () {
ff=--ff
+
case "$1" in -n) sha1=$2; ff= ;; *) sha1=$1 ;; esac
case "$force_rebase" in '') ;; ?*) ff= ;; esac
output git rev-parse --verify $sha1 || die "Invalid commit name: $sha1"
+
+ if is_empty_commit "$sha1"
+ then
+ empty_args="--allow-empty"
+ fi
+
test -d "$rewritten" &&
pick_one_preserving_merges "$@" && return
- output git cherry-pick $ff "$@"
+ output git cherry-pick $empty_args $ff "$@"
}
pick_one_preserving_merges () {
@@ -780,9 +795,17 @@ git rev-list $merges_option --pretty=oneline --abbrev-commit \
sed -n "s/^>//p" |
while read -r shortsha1 rest
do
+
+ if test -z "$keep_empty" && is_empty_commit $shortsha1
+ then
+ comment_out="# "
+ else
+ comment_out=
+ fi
+
if test t != "$preserve_merges"
then
- printf '%s\n' "pick $shortsha1 $rest" >> "$todo"
+ printf '%s\n' "${comment_out}pick $shortsha1 $rest" >>"$todo"
else
sha1=$(git rev-parse $shortsha1)
if test -z "$rebase_root"
@@ -801,7 +824,7 @@ do
if test f = "$preserve"
then
touch "$rewritten"/$sha1
- printf '%s\n' "pick $shortsha1 $rest" >> "$todo"
+ printf '%s\n' "${comment_out}pick $shortsha1 $rest" >>"$todo"
fi
fi
done
@@ -853,6 +876,12 @@ cat >> "$todo" << EOF
#
EOF
+if test -z "$keep_empty"
+then
+ echo "# Note that empty commits are commented out" >>"$todo"
+fi
+
+
has_action "$todo" ||
die_abort "Nothing to do"
View
@@ -43,6 +43,7 @@ s,strategy=! use the given merge strategy
no-ff! cherry-pick all commits, even if unchanged
m,merge! use merging strategies to rebase
i,interactive! let the user edit the list of commits to rebase
+k,keep-empty preserve empty commits during rebase
f,force-rebase! force rebase even if branch is up to date
X,strategy-option=! pass the argument through to the merge strategy
stat! display a diffstat of what changed upstream
@@ -97,6 +98,7 @@ state_dir=
action=
preserve_merges=
autosquash=
+keep_empty=
test "$(git config --bool rebase.autosquash)" = "true" && autosquash=t
read_basic_state () {
@@ -220,6 +222,9 @@ do
-i)
interactive_rebase=explicit
;;
+ -k)
+ keep_empty=yes
+ ;;
-p)
preserve_merges=t
test -z "$interactive_rebase" && interactive_rebase=implied
View
@@ -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(void)
+{
+ 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
@@ -260,21 +285,46 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
*/
static int run_git_commit(const char *defmsg, struct replay_opts *opts)
{
- /* 6 is max possible length of our args array including NULL */
- const char *args[6];
- int i = 0;
+ struct argv_array array;
+ int rc;
+
+ 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)
+ argv_array_push(&array, "--allow-empty");
+
+ rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
+ argv_array_clear(&array);
+ return rc;
+}
+
+static int is_original_commit_empty(struct commit *commit)
+{
+ const unsigned char *ptree_sha1;
+
+ 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 */
}
- args[i] = NULL;
- return run_command_v_opt(args, RUN_GIT_CMD);
+ return !hashcmp(ptree_sha1, commit->tree->object.sha1);
}
static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
@@ -286,6 +336,8 @@ 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;
+ int index_unchanged;
if (opts->no_commit) {
/*
@@ -411,6 +463,10 @@ 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.
@@ -431,6 +487,25 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
print_advice(res == 1, opts);
rerere(opts->allow_rerere_auto);
} else {
+ index_unchanged = is_index_unchanged();
+ /*
+ * If index_unchanged is less than 0, that indicates we either
+ * couldn't parse HEAD or the index, so error out here.
+ */
+ if (index_unchanged < 0)
+ return index_unchanged;
+
+ if (!empty_commit && !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;
+
if (!opts->no_commit)
res = run_git_commit(defmsg, opts);
}
View
@@ -29,6 +29,8 @@ struct replay_opts {
int signoff;
int allow_ff;
int allow_rerere_auto;
+ int allow_empty;
+ int keep_redundant_commits;
int mainline;
@@ -18,7 +18,12 @@ test_expect_success setup '
echo third >> file1 &&
git add file1 &&
test_tick &&
- git commit --allow-empty-message -m ""
+ git commit --allow-empty-message -m "" &&
+
+ git checkout master &&
+ git checkout -b empty-branch2 &&
+ test_tick &&
+ git commit --allow-empty -m "empty"
'
@@ -48,4 +53,22 @@ test_expect_success 'index lockfile was removed' '
'
+test_expect_success 'cherry pick an empty non-ff commit without --allow-empty' '
+ git checkout master &&
+ echo fourth >>file2 &&
+ git add file2 &&
+ git commit -m "fourth" &&
+ test_must_fail git cherry-pick empty-branch2
+'
+
+test_expect_success 'cherry pick an empty non-ff commit with --allow-empty' '
+ git checkout master &&
+ git cherry-pick --allow-empty empty-branch2
+'
+
+test_expect_success 'cherry pick with --keep-redundant-commits' '
+ git checkout master &&
+ git cherry-pick --keep-redundant-commits HEAD^
+'
+
test_done

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