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[PATCH v6 02/10] rebase -i: generate the script via rebase--helper

From
Johannes Schindelin <johannes.schindelin@gmx.de>
Date
Jul 14, 2017, 14:44 UTC
Message-ID
<814284075336e715dd52859e69aeb41226624af7.1500043437.git.johannes.schindelin@gmx.de>
In-Reply-To
<cover.1500043436.git.johannes.schindelin@gmx.de>

The first step of an interactive rebase is to generate the so-called "todo script", to be stored in the state directory as "git-rebase-todo" and to be edited by the user.

Originally, we adjusted the output of `git log <options>` using a simple sed script. Over the course of the years, the code became more complicated. We now use shell scripting to edit the output of `git log` conditionally, depending whether to keep "empty" commits (i.e. commits that do not change any files).

On platforms where shell scripting is not native, this can be a serious drag. And it opens the door for incompatibilities between platforms when it comes to shell scripting or to Unix-y commands.

Let's just re-implement the todo script generation in plain C, using the revision machinery directly.

This is substantially faster, improving the speed relative to the shell script version of the interactive rebase from 2x to 3x on Windows.

Note that the rearrange_squash() function in git-rebase--interactive relied on the fact that we set the "format" variable to the config setting rebase.instructionFormat. Relying on a side effect like this is no good, hence we explicitly perform that assignment (possibly again) in rearrange_squash().

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 builtin/rebase--helper.c   |  8 +++++++-
 git-rebase--interactive.sh | 44 +++++++++++++++++++++--------------------
 sequencer.c                | 49 ++++++++++++++++++++++++++++++++++++++++++++++
 sequencer.h                |  3 +++
 4 files changed, 82 insertions(+), 22 deletions(-)
diff --git a/builtin/rebase--helper.c b/builtin/rebase--helper.c
index c82b4dce683..613053276e6 100644
--- a/builtin/rebase--helper.c
+++ b/builtin/rebase--helper.c
@@ -12,15 +12,19 @@ static const char * const builtin_rebase_helper_usage[] = {
 int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
 {
 	struct replay_opts opts = REPLAY_OPTS_INIT;
+	int keep_empty = 0;
 	enum {
-		CONTINUE = 1, ABORT
+		CONTINUE = 1, ABORT, MAKE_SCRIPT
 	} command = 0;
 	struct option options[] = {
 		OPT_BOOL(0, "ff", &opts.allow_ff, N_("allow fast-forward")),
+		OPT_BOOL(0, "keep-empty", &keep_empty, N_("keep empty commits")),
 		OPT_CMDMODE(0, "continue", &command, N_("continue rebase"),
 				CONTINUE),
 		OPT_CMDMODE(0, "abort", &command, N_("abort rebase"),
 				ABORT),
+		OPT_CMDMODE(0, "make-script", &command,
+			N_("make rebase script"), MAKE_SCRIPT),
 		OPT_END()
 	};
 
@@ -37,5 +41,7 @@ int cmd_rebase__helper(int argc, const char **argv, const char *prefix)
 		return !!sequencer_continue(&opts);
 	if (command == ABORT && argc == 1)
 		return !!sequencer_remove_state(&opts);
+	if (command == MAKE_SCRIPT && argc > 1)
+		return !!sequencer_make_script(keep_empty, stdout, argc, argv);
 	usage_with_options(builtin_rebase_helper_usage, options);
 }
diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
index 90b1fbe9cf6..05766835de1 100644
--- a/git-rebase--interactive.sh
+++ b/git-rebase--interactive.sh
@@ -785,6 +785,7 @@ collapse_todo_ids() {
 # each log message will be re-retrieved in order to normalize the
 # autosquash arrangement
 rearrange_squash () {
+	format=$(git config --get rebase.instructionFormat)
 	# extract fixup!/squash! lines and resolve any referenced sha1's
 	while read -r pick sha1 message
 	do
@@ -1210,26 +1211,27 @@ else
 	revisions=$onto...$orig_head
 	shortrevisions=$shorthead
 fi
-format=$(git config --get rebase.instructionFormat)
-# the 'rev-list .. | sed' requires %m to parse; the instruction requires %H to parse
-git rev-list $merges_option --format="%m%H ${format:-%s}" \
-	--reverse --left-right --topo-order \
-	$revisions ${restrict_revision+^$restrict_revision} | \
-	sed -n "s/^>//p" |
-while read -r sha1 rest
-do
-
-	if test -z "$keep_empty" && is_empty_commit $sha1 && ! is_merge_commit $sha1
-	then
-		comment_out="$comment_char "
-	else
-		comment_out=
-	fi
+if test t != "$preserve_merges"
+then
+	git rebase--helper --make-script ${keep_empty:+--keep-empty} \
+		$revisions ${restrict_revision+^$restrict_revision} >"$todo"
+else
+	format=$(git config --get rebase.instructionFormat)
+	# the 'rev-list .. | sed' requires %m to parse; the instruction requires %H to parse
+	git rev-list $merges_option --format="%m%H ${format:-%s}" \
+		--reverse --left-right --topo-order \
+		$revisions ${restrict_revision+^$restrict_revision} | \
+		sed -n "s/^>//p" |
+	while read -r sha1 rest
+	do
+
+		if test -z "$keep_empty" && is_empty_commit $sha1 && ! is_merge_commit $sha1
+		then
+			comment_out="$comment_char "
+		else
+			comment_out=
+		fi
 
-	if test t != "$preserve_merges"
-	then
-		printf '%s\n' "${comment_out}pick $sha1 $rest" >>"$todo"
-	else
 		if test -z "$rebase_root"
 		then
 			preserve=t
@@ -1248,8 +1250,8 @@ do
 			touch "$rewritten"/$sha1
 			printf '%s\n' "${comment_out}pick $sha1 $rest" >>"$todo"
 		fi
-	fi
-done
+	done
+fi
 
 # Watch for commits that been dropped by --cherry-pick
 if test t = "$preserve_merges"
diff --git a/sequencer.c b/sequencer.c
index 3010faf8639..afcb3d00a32 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -2413,3 +2413,52 @@ void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
 
 	strbuf_release(&sob);
 }
+
+int sequencer_make_script(int keep_empty, FILE *out,
+		int argc, const char **argv)
+{
+	char *format = NULL;
+	struct pretty_print_context pp = {0};
+	struct strbuf buf = STRBUF_INIT;
+	struct rev_info revs;
+	struct commit *commit;
+
+	init_revisions(&revs, NULL);
+	revs.verbose_header = 1;
+	revs.max_parents = 1;
+	revs.cherry_pick = 1;
+	revs.limited = 1;
+	revs.reverse = 1;
+	revs.right_only = 1;
+	revs.sort_order = REV_SORT_IN_GRAPH_ORDER;
+	revs.topo_order = 1;
+
+	revs.pretty_given = 1;
+	git_config_get_string("rebase.instructionFormat", &format);
+	if (!format || !*format) {
+		free(format);
+		format = xstrdup("%s");
+	}
+	get_commit_format(format, &revs);
+	free(format);
+	pp.fmt = revs.commit_format;
+	pp.output_encoding = get_log_output_encoding();
+
+	if (setup_revisions(argc, argv, &revs, NULL) > 1)
+		return error(_("make_script: unhandled options"));
+
+	if (prepare_revision_walk(&revs) < 0)
+		return error(_("make_script: error preparing revisions"));
+
+	while ((commit = get_revision(&revs))) {
+		strbuf_reset(&buf);
+		if (!keep_empty && is_original_commit_empty(commit))
+			strbuf_addf(&buf, "%c ", comment_line_char);
+		strbuf_addf(&buf, "pick %s ", oid_to_hex(&commit->object.oid));
+		pretty_print_commit(&pp, commit, &buf);
+		strbuf_addch(&buf, '\n');
+		fputs(buf.buf, out);
+	}
+	strbuf_release(&buf);
+	return 0;
+}
diff --git a/sequencer.h b/sequencer.h
index f885b68395f..83f2943b7a9 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -45,6 +45,9 @@ int sequencer_continue(struct replay_opts *opts);
 int sequencer_rollback(struct replay_opts *opts);
 int sequencer_remove_state(struct replay_opts *opts);
 
+int sequencer_make_script(int keep_empty, FILE *out,
+		int argc, const char **argv);
+
 extern const char sign_off_header[];
 
 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag);

-- 
2.13.3.windows.1.13.gaf0c2223da0
Previous: Johannes SchindelinNext: Stefan Beller
Message 4 of 17 in “The final building block for a faster rebase -i”
  1. 00/10 The final building block for a faster rebase -iJohannes Schindelin, Jul 14, 2017
  2. 01/10 t3415: verify that an empty instructionFormat is handled as beforeJohannes Schindelin, Jul 14, 2017
  3. 03/10 rebase -i: remove useless indentationJohannes Schindelin, Jul 14, 2017
  4. 02/10 rebase -i: generate the script via rebase--helperJohannes Schindelin, Jul 14, 2017
  5. Stefan BellerJul 14, 2017
  6. Johannes SchindelinJul 15, 2017
  7. 04/10 rebase -i: do not invent onelines when expanding/collapsing SHA-1sJohannes Schindelin, Jul 14, 2017
  8. 05/10 rebase -i: also expand/collapse the SHA-1s via the rebase--helperJohannes Schindelin, Jul 14, 2017
  9. 06/10 t3404: relax rebase.missingCommitsCheck testsJohannes Schindelin, Jul 14, 2017
  10. 07/10 rebase -i: check for missing commits in the rebase--helperJohannes Schindelin, Jul 14, 2017
  11. 09/10 t3415: test fixup with wrapped onelineJohannes Schindelin, Jul 14, 2017
  12. 08/10 rebase -i: skip unnecessary picks using the rebase--helperJohannes Schindelin, Jul 14, 2017
  13. 10/10 rebase -i: rearrange fixup/squash lines using the rebase--helperJohannes Schindelin, Jul 14, 2017
  14. Stefan BellerJul 14, 2017
  15. Johannes SchindelinJul 14, 2017
  16. Junio C HamanoJul 20, 2017
  17. Johannes SchindelinJul 22, 2017

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