[PATCH v6 10/10] rebase -i: rearrange fixup/squash lines using the rebase--helper
This operation has quadratic complexity, which is especially painful on Windows, where shell scripts are *already* slow (mainly due to the overhead of the POSIX emulation layer).
Let's reimplement this with linear complexity (using a hash map to match the commits' subject lines) for the common case; Sadly, the fixup/squash feature's design neglected performance considerations, allowing arbitrary prefixes (read: `fixup! hell` will match the commit subject `hello world`), which means that we are stuck with quadratic performance in the worst case.
The reimplemented logic also happens to fix a bug where commented-out lines (representing empty patches) were dropped by the previous code.
While at it, clarify how the fixup/squash feature works in `git rebase -i`'s man page.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
Documentation/git-rebase.txt | 16 ++--
builtin/rebase--helper.c | 6 +-
git-rebase--interactive.sh | 90 +-------------------
sequencer.c | 196 +++++++++++++++++++++++++++++++++++++++++++
sequencer.h | 1 +
t/t3415-rebase-autosquash.sh | 2 +-
6 files changed, 213 insertions(+), 98 deletions(-)
Show changes to 6 files +213 −98
Documentation/git-rebase.txt, builtin/rebase--helper.c, git-rebase--interactive.sh, sequencer.c, sequencer.h, t/t3415-rebase-autosquash.sh
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index 4f6bed61a92..a3c01dfdc8a 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -430,13 +430,15 @@ without an explicit `--interactive`.
--autosquash::
--no-autosquash::
When the commit log message begins with "squash! ..." (or
- "fixup! ..."), and there is a commit whose title begins with
- the same ..., automatically modify the todo list of rebase -i
- so that the commit marked for squashing comes right after the
- commit to be modified, and change the action of the moved
- commit from `pick` to `squash` (or `fixup`). Ignores subsequent
- "fixup! " or "squash! " after the first, in case you referred to an
- earlier fixup/squash with `git commit --fixup/--squash`.
+ "fixup! ..."), and there is already a commit in the todo list that
+ matches the same `...`, automatically modify the todo list of rebase
+ -i so that the commit marked for squashing comes right after the
+ commit to be modified, and change the action of the moved commit
+ from `pick` to `squash` (or `fixup`). A commit matches the `...` if
+ the commit subject matches, or if the `...` refers to the commit's
+ hash. As a fall-back, partial matches of the commit subject work,
+ too. The recommended way to create fixup/squash commits is by using
+ the `--fixup`/`--squash` options of linkgit:git-commit[1].
+
This option is only valid when the `--interactive` option is used.
+
diff --git a/builtin/rebase--helper.c b/builtin/rebase--helper.c
index 057ae7102ff..f8519363a39 100644
--- a/builtin/rebase--helper.c
+++ b/builtin/rebase--helper.c
@@ -15,7 +15,7 @@ int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
int keep_empty = 0;
enum {
CONTINUE = 1, ABORT, MAKE_SCRIPT, SHORTEN_SHA1S, EXPAND_SHA1S,
- CHECK_TODO_LIST, SKIP_UNNECESSARY_PICKS
+ CHECK_TODO_LIST, SKIP_UNNECESSARY_PICKS, REARRANGE_SQUASH
} command = 0;
struct option options[] = {
OPT_BOOL(0, "ff", &opts.allow_ff, N_("allow fast-forward")),
@@ -34,6 +34,8 @@ int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
N_("check the todo list"), CHECK_TODO_LIST),
OPT_CMDMODE(0, "skip-unnecessary-picks", &command,
N_("skip unnecessary picks"), SKIP_UNNECESSARY_PICKS),
+ OPT_CMDMODE(0, "rearrange-squash", &command,
+ N_("rearrange fixup/squash lines"), REARRANGE_SQUASH),
OPT_END()
};
@@ -60,5 +62,7 @@ int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
return !!check_todo_list();
if (command == SKIP_UNNECESSARY_PICKS && argc == 1)
return !!skip_unnecessary_picks();
+ if (command == REARRANGE_SQUASH && argc == 1)
+ return !!rearrange_squash();
usage_with_options(builtin_rebase_helper_usage, options);
}
diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
index af8d7bd77fb..3b0340e7cc9 100644
--- a/git-rebase--interactive.sh
+++ b/git-rebase--interactive.sh
@@ -721,94 +721,6 @@ collapse_todo_ids() {
git rebase--helper --shorten-ids
}
-# Rearrange the todo list that has both "pick sha1 msg" and
-# "pick sha1 fixup!/squash! msg" appears in it so that the latter
-# comes immediately after the former, and change "pick" to
-# "fixup"/"squash".
-#
-# Note that if the config has specified a custom instruction format
-# each log message will be re-retrieved in order to normalize the
-# autosquash arrangement
-rearrange_squash () {
- format=$(git config --get rebase.instructionFormat)
- # extract fixup!/squash! lines and resolve any referenced sha1's
- while read -r pick sha1 message
- do
- test -z "${format}" || message=$(git log -n 1 --format="%s" ${sha1})
- case "$message" in
- "squash! "*|"fixup! "*)
- action="${message%%!*}"
- rest=$message
- prefix=
- # skip all squash! or fixup! (but save for later)
- while :
- do
- case "$rest" in
- "squash! "*|"fixup! "*)
- prefix="$prefix${rest%%!*},"
- rest="${rest#*! }"
- ;;
- *)
- break
- ;;
- esac
- done
- printf '%s %s %s %s\n' "$sha1" "$action" "$prefix" "$rest"
- # if it's a single word, try to resolve to a full sha1 and
- # emit a second copy. This allows us to match on both message
- # and on sha1 prefix
- if test "${rest#* }" = "$rest"; then
- fullsha="$(git rev-parse -q --verify "$rest" 2>/dev/null)"
- if test -n "$fullsha"; then
- # prefix the action to uniquely identify this line as
- # intended for full sha1 match
- echo "$sha1 +$action $prefix $fullsha"
- fi
- fi
- esac
- done >"$1.sq" <"$1"
- test -s "$1.sq" || return
-
- used=
- while read -r pick sha1 message
- do
- case " $used" in
- *" $sha1 "*) continue ;;
- esac
- printf '%s\n' "$pick $sha1 $message"
- test -z "${format}" || message=$(git log -n 1 --format="%s" ${sha1})
- used="$used$sha1 "
- while read -r squash action msg_prefix msg_content
- do
- case " $used" in
- *" $squash "*) continue ;;
- esac
- emit=0
- case "$action" in
- +*)
- action="${action#+}"
- # full sha1 prefix test
- case "$msg_content" in "$sha1"*) emit=1;; esac ;;
- *)
- # message prefix test
- case "$message" in "$msg_content"*) emit=1;; esac ;;
- esac
- if test $emit = 1; then
- if test -n "${format}"
- then
- msg_content=$(git log -n 1 --format="${format}" ${squash})
- else
- msg_content="$(echo "$msg_prefix" | sed "s/,/! /g")$msg_content"
- fi
- printf '%s\n' "$action $squash $msg_content"
- used="$used$squash "
- fi
- done <"$1.sq"
- done >"$1.rearranged" <"$1"
- cat "$1.rearranged" >"$1"
- rm -f "$1.sq" "$1.rearranged"
-}
-
# Add commands after a pick or after a squash/fixup serie
# in the todo list.
add_exec_commands () {
@@ -1068,7 +980,7 @@ then
fi
test -s "$todo" || echo noop >> "$todo"
-test -n "$autosquash" && rearrange_squash "$todo"
+test -z "$autosquash" || git rebase--helper --rearrange-squash || exit
test -n "$cmd" && add_exec_commands "$todo"
todocount=$(git stripspace --strip-comments <"$todo" | wc -l)
diff --git a/sequencer.c b/sequencer.c
index 96d43aec764..c54596f9699 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -20,6 +20,7 @@
#include "trailer.h"
#include "log-tree.h"
#include "wt-status.h"
+#include "hashmap.h"
#define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
@@ -2748,3 +2749,198 @@ int skip_unnecessary_picks(void)
return 0;
}
+
+struct subject2item_entry {
+ struct hashmap_entry entry;
+ int i;
+ char subject[FLEX_ARRAY];
+};
+
+static int subject2item_cmp(const void *fndata,
+ const struct subject2item_entry *a,
+ const struct subject2item_entry *b, const void *key)
+{
+ return key ? strcmp(a->subject, key) : strcmp(a->subject, b->subject);
+}
+
+/*
+ * Rearrange the todo list that has both "pick commit-id msg" and "pick
+ * commit-id fixup!/squash! msg" in it so that the latter is put immediately
+ * after the former, and change "pick" to "fixup"/"squash".
+ *
+ * Note that if the config has specified a custom instruction format, each log
+ * message will have to be retrieved from the commit (as the oneline in the
+ * script cannot be trusted) in order to normalize the autosquash arrangement.
+ */
+int rearrange_squash(void)
+{
+ const char *todo_file = rebase_path_todo();
+ struct todo_list todo_list = TODO_LIST_INIT;
+ struct hashmap subject2item;
+ int res = 0, rearranged = 0, *next, *tail, fd, i;
+ char **subjects;
+
+ fd = open(todo_file, O_RDONLY);
+ if (fd < 0)
+ return error_errno(_("could not open '%s'"), todo_file);
+ if (strbuf_read(&todo_list.buf, fd, 0) < 0) {
+ close(fd);
+ return error(_("could not read '%s'."), todo_file);
+ }
+ close(fd);
+ if (parse_insn_buffer(todo_list.buf.buf, &todo_list) < 0) {
+ todo_list_release(&todo_list);
+ return -1;
+ }
+
+ /*
+ * The hashmap maps onelines to the respective todo list index.
+ *
+ * If any items need to be rearranged, the next[i] value will indicate
+ * which item was moved directly after the i'th.
+ *
+ * In that case, last[i] will indicate the index of the latest item to
+ * be moved to appear after the i'th.
+ */
+ hashmap_init(&subject2item, (hashmap_cmp_fn) subject2item_cmp,
+ NULL, todo_list.nr);
+ ALLOC_ARRAY(next, todo_list.nr);
+ ALLOC_ARRAY(tail, todo_list.nr);
+ ALLOC_ARRAY(subjects, todo_list.nr);
+ for (i = 0; i < todo_list.nr; i++) {
+ struct strbuf buf = STRBUF_INIT;
+ struct todo_item *item = todo_list.items + i;
+ const char *commit_buffer, *subject, *p;
+ size_t subject_len;
+ int i2 = -1;
+ struct subject2item_entry *entry;
+
+ next[i] = tail[i] = -1;
+ if (item->command >= TODO_EXEC) {
+ subjects[i] = NULL;
+ continue;
+ }
+
+ if (is_fixup(item->command)) {
+ todo_list_release(&todo_list);
+ return error(_("the script was already rearranged."));
+ }
+
+ item->commit->util = item;
+
+ parse_commit(item->commit);
+ commit_buffer = get_commit_buffer(item->commit, NULL);
+ find_commit_subject(commit_buffer, &subject);
+ format_subject(&buf, subject, " ");
+ subject = subjects[i] = strbuf_detach(&buf, &subject_len);
+ unuse_commit_buffer(item->commit, commit_buffer);
+ if ((skip_prefix(subject, "fixup! ", &p) ||
+ skip_prefix(subject, "squash! ", &p))) {
+ struct commit *commit2;
+
+ for (;;) {
+ while (isspace(*p))
+ p++;
+ if (!skip_prefix(p, "fixup! ", &p) &&
+ !skip_prefix(p, "squash! ", &p))
+ break;
+ }
+
+ if ((entry = hashmap_get_from_hash(&subject2item,
+ strhash(p), p)))
+ /* found by title */
+ i2 = entry->i;
+ else if (!strchr(p, ' ') &&
+ (commit2 =
+ lookup_commit_reference_by_name(p)) &&
+ commit2->util)
+ /* found by commit name */
+ i2 = (struct todo_item *)commit2->util
+ - todo_list.items;
+ else {
+ /* copy can be a prefix of the commit subject */
+ for (i2 = 0; i2 < i; i2++)
+ if (subjects[i2] &&
+ starts_with(subjects[i2], p))
+ break;
+ if (i2 == i)
+ i2 = -1;
+ }
+ }
+ if (i2 >= 0) {
+ rearranged = 1;
+ todo_list.items[i].command =
+ starts_with(subject, "fixup!") ?
+ TODO_FIXUP : TODO_SQUASH;
+ if (next[i2] < 0)
+ next[i2] = i;
+ else
+ next[tail[i2]] = i;
+ tail[i2] = i;
+ } else if (!hashmap_get_from_hash(&subject2item,
+ strhash(subject), subject)) {
+ FLEX_ALLOC_MEM(entry, subject, subject, subject_len);
+ entry->i = i;
+ hashmap_entry_init(entry, strhash(entry->subject));
+ hashmap_put(&subject2item, entry);
+ }
+ }
+
+ if (rearranged) {
+ struct strbuf buf = STRBUF_INIT;
+
+ for (i = 0; i < todo_list.nr; i++) {
+ enum todo_command command = todo_list.items[i].command;
+ int cur = i;
+
+ /*
+ * Initially, all commands are 'pick's. If it is a
+ * fixup or a squash now, we have rearranged it.
+ */
+ if (is_fixup(command))
+ continue;
+
+ while (cur >= 0) {
+ int offset = todo_list.items[cur].offset_in_buf;
+ int end_offset = cur + 1 < todo_list.nr ?
+ todo_list.items[cur + 1].offset_in_buf :
+ todo_list.buf.len;
+ char *bol = todo_list.buf.buf + offset;
+ char *eol = todo_list.buf.buf + end_offset;
+
+ /* replace 'pick', by 'fixup' or 'squash' */
+ command = todo_list.items[cur].command;
+ if (is_fixup(command)) {
+ strbuf_addstr(&buf,
+ todo_command_info[command].str);
+ bol += strcspn(bol, " \t");
+ }
+
+ strbuf_add(&buf, bol, eol - bol);
+
+ cur = next[cur];
+ }
+ }
+
+ fd = open(todo_file, O_WRONLY);
+ if (fd < 0)
+ res = error_errno(_("could not open '%s'"), todo_file);
+ else if (write(fd, buf.buf, buf.len) < 0)
+ res = error_errno(_("could not read '%s'."), todo_file);
+ else if (ftruncate(fd, buf.len) < 0)
+ res = error_errno(_("could not finish '%s'"),
+ todo_file);
+ close(fd);
+ strbuf_release(&buf);
+ }
+
+ free(next);
+ free(tail);
+ for (i = 0; i < todo_list.nr; i++)
+ free(subjects[i]);
+ free(subjects);
+ hashmap_free(&subject2item, 1);
+ todo_list_release(&todo_list);
+
+ return res;
+}
diff --git a/sequencer.h b/sequencer.h
index 04a57e09a1d..6f3d3df82c0 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -51,6 +51,7 @@ int sequencer_make_script(int keep_empty, FILE *out,
int transform_todo_ids(int shorten_ids);
int check_todo_list(void);
int skip_unnecessary_picks(void);
+int rearrange_squash(void);
extern const char sign_off_header[];
diff --git a/t/t3415-rebase-autosquash.sh b/t/t3415-rebase-autosquash.sh
index 62cb977e4ec..e364c12622f 100755
--- a/t/t3415-rebase-autosquash.sh
+++ b/t/t3415-rebase-autosquash.sh
@@ -290,7 +290,7 @@ set_backup_editor () {
test_set_editor "$PWD/backup-editor.sh"
}
-test_expect_failure 'autosquash with multiple empty patches' '
+test_expect_success 'autosquash with multiple empty patches' '
test_tick &&
git commit --allow-empty -m "empty" &&
test_tick &&
Johannes Schindelin
