Subject: [PATCH v4 0/1] range-diff: treat notes like `log`

From: Kristoffer Haugsbakk <[email-masked]>
Date: Tue, 19 Sep 2023 20:05:31 +0200

Hi

Same cover letter up until but not including “Changes ...”.

Cheers

🙛 🙙

Currently, `range-diff` shows the default notes if no notes-related
arguments are given. This is also how `log` behaves. But unlike
`range-diff`, `log` does *not* show the default notes if
`--notes=<custom>` are given.

These changes are supposed to make `format-range` behave like `log` with
regards to notes.

These changes also fixes an issue with notes being shared in the cover
letter via `range-diff`, and that’s really the main motivation for
making these changes.

§ How `log` works

`log` shows the default notes if no notes arguments are given. But if
you give it specific notes to show then it forgets about the default
notes. Further, there is the convenience `--notes` option which will
show the default notes again. These options are cumulative. For example:

    git log --notes --notes=custom

Will show the default notes as well as the `custom` notes.

See discussion in: https://lore.kernel.org/git/[email-masked]/

§ How `range-format` works

`range-format` passes `--notes` to `log`, which means that it does not
have the default behavior of `log` (forget the default logs if you say
e.g. `--notes=custom`). However, the man page says that (under
`--[no-]notes[=<ref>]`):

> This flag is passed to the git log program (see git-log(1)) that generates the patches.

This makes me (at least) think that `range-format` is supposed to work
just like `log` with regards to notes.

§ `format-patch` and the difference between showing and sharing

`format-patch` has a different default: it shows no notes. This makes
sense in my opinion since `format-patch` is meant to be used to share
changes with others, and you might be surprised if your notes (which
might have only been notes to yourself) are sent out in your emails
(keep in mind that notes refs are *not* pushed by default).

But the slightly faulty behavior of `range-diff` bleeds through to
`format-patch` since the latter calls the former; if you have default
notes they can be shared in the range-diff on the cover letter, even
though `format-patch` isn’t supposed to show them.

§ Changes since version 3

Dscho [rewrote] the fix: introduce a new option to pass to `git log`.

🔗 rewrote: https://lore.kernel.org/git/[email-masked]/

§ CI (WIP)

https://github.com/LemmingAvalanche/git/actions/runs/6238806624

Kristoffer Haugsbakk (1):
  range-diff: treat notes like `log`

 Documentation/pretty-options.txt |  4 ++++
 range-diff.c                     |  2 +-
 revision.c                       |  7 +++++++
 revision.h                       |  1 +
 t/t3206-range-diff.sh            | 28 ++++++++++++++++++++++++++++
 5 files changed, 41 insertions(+), 1 deletion(-)

Range-diff against v3:
1:  a37dfb3748 ! 1:  244e102cc4 range-diff: treat notes like `log`
    @@ Commit message
         to say about the changes to the default notes, since that will be shown
         in the cover letter.

    -    Remedy this by only conditionally passing in `--notes` to `range-diff`.
    +    Remedy this by introducing `--show-notes-by-default` that `range-diff` can
    +    use to tell the `log` subprocess what to do.

         § Root cause

    @@ Commit message
         Co-authored-by: Johannes Schindelin <[email-masked]>
         Signed-off-by: Kristoffer Haugsbakk <[email-masked]>

    - ## range-diff.c ##
    -@@ range-diff.c: static int read_patches(const char *range, struct string_list *list,
    - 	struct child_process cp = CHILD_PROCESS_INIT;
    - 	struct strbuf buf = STRBUF_INIT, contents = STRBUF_INIT;
    - 	struct patch_util *util = NULL;
    --	int in_header = 1;
    -+	int i, implicit_notes_arg = 1, in_header = 1;
    - 	char *line, *current_filename = NULL;
    - 	ssize_t len;
    - 	size_t size;
    - 	int ret = -1;
    + ## Documentation/pretty-options.txt ##
    +@@ Documentation/pretty-options.txt: message by 4 spaces (i.e.  'medium', which is the default, 'full',
    + and 'fuller').

    -+	for (i = 0; other_arg && i < other_arg->nr; i++)
    -+		if (!strcmp(other_arg->v[i], "--notes") ||
    -+		    starts_with(other_arg->v[i], "--notes=") ||
    -+		    !strcmp(other_arg->v[i], "--no-notes")) {
    -+			implicit_notes_arg = 0;
    -+			break;
    -+		}
    + ifndef::git-rev-list[]
    ++--show-notes-by-default::
    ++	Show the default notes (see `--notes`) unless subsequent arguments
    ++	are used to display specific notes.
     +
    - 	strvec_pushl(&cp.args, "log", "--no-color", "-p", "--no-merges",
    - 		     "--reverse", "--date-order", "--decorate=no",
    - 		     "--no-prefix", "--submodule=short",
    + --notes[=<ref>]::
    + 	Show the notes (see linkgit:git-notes[1]) that annotate the
    + 	commit, when showing the commit log message.  This is the default
    +
    + ## range-diff.c ##
     @@ range-diff.c: static int read_patches(const char *range, struct string_list *list,
      		     "--output-indicator-context=#",
      		     "--no-abbrev-commit",
      		     "--pretty=medium",
     -		     "--notes",
    ++		     "--show-notes-by-default",
      		     NULL);
    -+	if (implicit_notes_arg)
    -+		     strvec_push(&cp.args, "--notes");
      	strvec_push(&cp.args, range);
      	if (other_arg)
    - 		strvec_pushv(&cp.args, other_arg->v);
    +
    + ## revision.c ##
    +@@ revision.c: static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
    + 		revs->break_bar = xstrdup(optarg);
    + 		revs->track_linear = 1;
    + 		revs->track_first_time = 1;
    ++	} else if (!strcmp(arg, "--show-notes-by-default")) {
    ++		revs->show_notes_by_default = 1;
    + 	} else if (skip_prefix(arg, "--show-notes=", &optarg) ||
    + 		   skip_prefix(arg, "--notes=", &optarg)) {
    + 		if (starts_with(arg, "--show-notes=") &&
    +@@ revision.c: int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
    + 	if (revs->expand_tabs_in_log < 0)
    + 		revs->expand_tabs_in_log = revs->expand_tabs_in_log_default;
    +
    ++	if (!revs->show_notes_given && revs->show_notes_by_default) {
    ++		enable_default_display_notes(&revs->notes_opt, &revs->show_notes);
    ++		revs->show_notes_given = 1;
    ++	}
    ++
    + 	return left;
    + }
    +
    +
    + ## revision.h ##
    +@@ revision.h: struct rev_info {
    + 			shown_dashes:1,
    + 			show_merge:1,
    + 			show_notes_given:1,
    ++			show_notes_by_default:1,
    + 			show_signature:1,
    + 			pretty_given:1,
    + 			abbrev_commit:1,

      ## t/t3206-range-diff.sh ##
     @@ t/t3206-range-diff.sh: test_expect_success 'range-diff with multiple --notes' '
--
2.42.0