[v3,1/4] rebase -i: mark commits that begin empty in todo editor

Commit Message

John Passaro via GitGitGadget April 11, 2020, 2:44 a.m. UTC

From: Elijah Newren <[e-mail]>

While many users who intentionally create empty commits do not want them
thrown away by a rebase, there are third-party tools that generate empty
commits that a user might not want.  In the past, users have used rebase
to get rid of such commits (a side-effect of the fact that the --apply
backend is not currently capable of keeping them).  While such users
could fire up an interactive rebase and just remove the lines
corresponding to empty commits, that might be difficult if the
third-party tool generates many of them.  Simplify this task for users
by marking such lines with a suffix of " # empty" in the todo list.

Suggested-by: Sami Boukortt <[e-mail]>
Signed-off-by: Elijah Newren <[e-mail]>
---
 Documentation/git-rebase.txt | 3 ++-
 sequencer.c                  | 5 +++++
 2 files changed, 7 insertions(+), 1 deletion(-)

Comments

Junio C Hamano April 15, 2020, 8:52 p.m. UTC | #1

"Elijah Newren via GitGitGadget" <[e-mail]> writes:

> diff --git a/sequencer.c b/sequencer.c
> index e528225e787..ce9fd27a878 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -4656,6 +4656,9 @@ static int make_script_with_merges(struct pretty_print_context *pp,
>  			strbuf_addf(&buf, "%s %s %s", cmd_pick,
>  				    oid_to_hex(&commit->object.oid),
>  				    oneline.buf);
> +			if (is_empty)
> +				strbuf_addf(&buf, " %c empty",
> +					    comment_line_char);
> ...
> @@ -4861,6 +4864,8 @@ int sequencer_make_script(struct repository *r, struct strbuf *out,>  		pretty_print_commit(&pp, commit, out);
> +		if (is_empty)
> +			strbuf_addf(out, " %c empty", comment_line_char);
>  		strbuf_addch(out, '\n');

While I was re-reviewing the topics in flight, it occurred to me
that this change may hurt automation if people feed the insn file to
their own machinery to process, as the title in "git log --oneline"
and in the file no longer matches.  I am not sure how big a deal is
(even when I am scripting, I only use the commit object name and
ignore the title string, but there are people with diferent taste in
this world, so...).  It might be safer to add this as a comment on
its own line, next to the usual "pick <commit> <title>" line, but I
dunno.

This is more about raising awareness of possible regression than a
suggestion to change anything.

Thanks.

Patch

diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index f7a6033607f..8ab0558aca2 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -620,7 +620,8 @@  commits that started empty, though these are rare in practice.  It
 also drops commits that become empty and has no option for controlling
 this behavior.
 
-The merge backend keeps intentionally empty commits.  Similar to the
+The merge backend keeps intentionally empty commits (though with -i
+they are marked as empty in the todo list editor).  Similar to the
 apply backend, by default the merge backend drops commits that become
 empty unless -i/--interactive is specified (in which case it stops and
 asks the user what to do).  The merge backend also has an
diff --git a/sequencer.c b/sequencer.c
index e528225e787..ce9fd27a878 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -4656,6 +4656,9 @@  static int make_script_with_merges(struct pretty_print_context *pp,
 			strbuf_addf(&buf, "%s %s %s", cmd_pick,
 				    oid_to_hex(&commit->object.oid),
 				    oneline.buf);
+			if (is_empty)
+				strbuf_addf(&buf, " %c empty",
+					    comment_line_char);
 
 			FLEX_ALLOC_STR(entry, string, buf.buf);
 			oidcpy(&entry->entry.oid, &commit->object.oid);
@@ -4861,6 +4864,8 @@  int sequencer_make_script(struct repository *r, struct strbuf *out, int argc,
 		strbuf_addf(out, "%s %s ", insn,
 			    oid_to_hex(&commit->object.oid));
 		pretty_print_commit(&pp, commit, out);
+		if (is_empty)
+			strbuf_addf(out, " %c empty", comment_line_char);
 		strbuf_addch(out, '\n');
 	}
 	return 0;