When I reimplemented the most performance-critical bits of the interactive rebase in the sequencer, to speed up `git rebase -i` particularly on Windows (even if the benefits are still quite notable on Linux or macOS), I punted on the --root part.
I had always hoped that some other contributor (or I myself) would come back later to address the --root part in the sequencer, too, with the idea that this would move the last remaining complicated code from git-rebase--interactive.sh into sequencer.c, to facilitate converting the rest of git-rebase--interactive.sh.
When I say "the last remaining complicated code", of course I neglect the --preserve-merges code, but as I worked hard on the --rebase-merges patch series with the intention to eventually deprecate and maybe even remove the --preserve-merges mode, I always implicitly assume that the --preserve-merges code will be moved into its own shell script (git-rebase--preserve-merges.sh, maybe?) and never be converted.
So here goes: the patches to move the handling of --root into the sequencer. After two preparatory patches, the real conversion takes place in the third patch. After that, we take care of the --root related concerns that arise in conjunction with the --rebase-merges mode.
As the --rebase-merges/--root patches overlap quite a bit (not so much in the code itself as in philosophical considerations such as "what should happen if you try to merge a branch into a new root", or the fact that the label/reset/merge commands make it desirable to be able to create a new root commit in the middle of a todo list), I had to consider in which order to contribute them. In the end, I decided to go with --rebase-merges first, so the --root patches are based on the --rebase-merges patch series.
I consider this patch series a critical prerequisite for Alban's Google Summer of Code project to convert rebase -i into a builtin.
Changes since v1:
- Expanded is_pick_or_similar() to use a clear and verbose switch()
statement, replacing the magic "command <= TODO_SQUASH".
- Completely revamped read_author_ident(), using sq_dequote(); Sadly,
trying to reuse builtin/am.c's read_author_script() would result in
substantialy more lines of code, and I also failed to find an easy way
to allow for arbitrary order of the environment variables in
author-script.
Johannes Schindelin (6):
sequencer: extract helper to update active_cache_tree
sequencer: learn about the special "fake root commit" handling
rebase -i --root: let the sequencer handle even the initial part
sequencer: allow introducing new root commits
rebase --rebase-merges: a "merge" into a new root is a fast-forward
rebase --rebase-merges: root commits can be cousins, too
git-rebase--interactive.sh | 4 +-
sequencer.c | 206 ++++++++++++++++++++++++++----
sequencer.h | 4 +
t/t3404-rebase-interactive.sh | 19 ++-
t/t3421-rebase-topology-linear.sh | 6 +-
t/t3430-rebase-merges.sh | 72 +++++++++++
6 files changed, 276 insertions(+), 35 deletions(-)
base-commit: 673fb9cb8b5c7d57cb560b6ade45e419c8dd09fc
Based-On: recreate-merges at https://github.com/dscho/git
Fetch-Base-Via: git fetch https://github.com/dscho/git recreate-merges
Published-As: https://github.com/dscho/git/releases/tag/sequencer-and-root-commits-v2
Fetch-It-Via: git fetch https://github.com/dscho/git sequencer-and-root-commits-v2
Branch-diff vs v1:
1: 42db734a980 ! 1: 73398da7119 sequencer: learn about the special "fake root commit" handling
@@ -54,40 +54,50 @@
return NULL;
}
++/* Read author-script and return an ident line (author <email> timestamp) */
+static const char *read_author_ident(struct strbuf *buf)
+{
-+ char *p, *p2;
++ const char *keys[] = {
++ "GIT_AUTHOR_NAME=", "GIT_AUTHOR_EMAIL=", "GIT_AUTHOR_DATE="
++ };
++ char *in, *out, *eol;
++ int i = 0, len;
+
+ if (strbuf_read_file(buf, rebase_path_author_script(), 256) <= 0)
+ return NULL;
+
-+ for (p = buf->buf; *p; p++)
-+ if (skip_prefix(p, "'\\\\''", (const char **)&p2))
-+ strbuf_splice(buf, p - buf->buf, p2 - p, "'", 1);
-+ else if (*p == '\'')
-+ strbuf_splice(buf, p-- - buf->buf, 1, "", 0);
-+
-+ if (skip_prefix(buf->buf, "GIT_AUTHOR_NAME=", (const char **)&p)) {
-+ strbuf_splice(buf, 0, p - buf->buf, "", 0);
-+ p = strchr(buf->buf, '\n');
-+ if (skip_prefix(p, "\nGIT_AUTHOR_EMAIL=", (const char **)&p2)) {
-+ strbuf_splice(buf, p - buf->buf, p2 - p, " <", 2);
-+ p = strchr(p, '\n');
-+ if (skip_prefix(p, "\nGIT_AUTHOR_DATE=@",
-+ (const char **)&p2)) {
-+ strbuf_splice(buf, p - buf->buf, p2 - p,
-+ "> ", 2);
-+ p = strchr(p, '\n');
-+ if (p) {
-+ strbuf_setlen(buf, p - buf->buf);
-+ return buf->buf;
-+ }
-+ }
++ /* dequote values and construct ident line in-place */
++ for (in = out = buf->buf; i < 3 && in - buf->buf < buf->len; i++) {
++ if (!skip_prefix(in, keys[i], (const char **)&in)) {
++ warning("could not parse '%s' (looking for '%s'",
++ rebase_path_author_script(), keys[i]);
++ return NULL;
+ }
-+ }
-+
-+ warning(_("could not parse '%s'"), rebase_path_author_script());
-+ return NULL;
++
++ eol = strchrnul(in, '\n');
++ *eol = '\0';
++ sq_dequote(in);
++ len = strlen(in);
++
++ if (i > 0) /* separate values by spaces */
++ *(out++) = ' ';
++ if (i == 1) /* email needs to be surrounded by <...> */
++ *(out++) = '<';
++ memmove(out, in, len);
++ out += len;
++ if (i == 1) /* email needs to be surrounded by <...> */
++ *(out++) = '>';
++ in = eol + 1;
++ }
++
++ if (i < 3) {
++ warning("could not parse '%s' (looking for '%s')",
++ rebase_path_author_script(), keys[i]);
++ return NULL;
++ }
++
++ buf->len = out - buf->buf;
++ return buf->buf;
+}
+
static const char staged_changes_advice[] =
@@ -159,7 +169,17 @@
+/* Does this command create a (non-merge) commit? */
+static int is_pick_or_similar(enum todo_command command)
+{
-+ return command <= TODO_SQUASH;
++ switch (command) {
++ case TODO_PICK:
++ case TODO_REVERT:
++ case TODO_EDIT:
++ case TODO_REWORD:
++ case TODO_FIXUP:
++ case TODO_SQUASH:
++ return 1;
++ default:
++ return 0;
++ }
+}
+
static int update_squash_messages(enum todo_command command,
2: 1c8740eaa91 = 2: 2dfe8315993 rebase -i --root: let the sequencer handle even the initial part
3: 8a7f5751412 = 3: 0ee765bbb36 sequencer: allow introducing new root commits
4: 0b7379b576b = 4: 29d7a9265e3 rebase --rebase-merges: a "merge" into a new root is a fast-forward
5: 270b8fdf477 = 5: f7ee1b3de12 rebase --rebase-merges: root commits can be cousins, too
Johannes Schindelin