[PATCH] merge/pull: --compact-summary

[PATCH] merge/pull: --compact-summary

[Junio C Hamano]

By default, "git merge" and "git pull" shows "git diff --stat @{1}"
to show the extent of the changes.  While it gives a good overview,
one thing that is missing in this output is which paths are created
and/or deleted.

Introduce "--compact-summary" option to these two commands that
tells it to instead show "git diff --compact-summary @{1}", which
gives the same diffstat but notes the created or deleted paths.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/git-merge.adoc     |  2 +-
 Documentation/merge-options.adoc |  3 +++
 builtin/merge.c                  | 39 ++++++++++++++++++++++++++++----
 builtin/pull.c                   |  3 +++
 t/t7600-merge.sh                 | 28 ++++++++++++++++++++++-
 5 files changed, 69 insertions(+), 6 deletions(-)

diff --git a/Documentation/git-merge.adoc b/Documentation/git-merge.adoc
index 12aa859d16..d53923c3b7 100644
--- a/Documentation/git-merge.adoc
+++ b/Documentation/git-merge.adoc
@@ -9,7 +9,7 @@ git-merge - Join two or more development histories together
 SYNOPSIS
 --------
 [synopsis]
-git merge [-n] [--stat] [--no-commit] [--squash] [--[no-]edit]
+git merge [-n] [--stat] [--compact-summary] [--no-commit] [--squash] [--[no-]edit]
 	[--no-verify] [-s <strategy>] [-X <strategy-option>] [-S[<keyid>]]
 	[--[no-]allow-unrelated-histories]
 	[--[no-]rerere-autoupdate] [-m <msg>] [-F <file>]
diff --git a/Documentation/merge-options.adoc b/Documentation/merge-options.adoc
index 078f4f6157..95ef491be1 100644
--- a/Documentation/merge-options.adoc
+++ b/Documentation/merge-options.adoc
@@ -113,6 +113,9 @@ include::signoff-option.adoc[]
 With `-n` or `--no-stat` do not show a diffstat at the end of the
 merge.
 
+`--compact-summary`::
+	Show a compact-summary at the end of the merge.
+
 `--squash`::
 `--no-squash`::
 	Produce the working tree and index state as if a real merge
diff --git a/builtin/merge.c b/builtin/merge.c
index ce90e52fe4..736739d3a9 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -69,7 +69,10 @@ static const char * const builtin_merge_usage[] = {
 	NULL
 };
 
-static int show_diffstat = 1, shortlog_len = -1, squash;
+#define MERGE_SHOW_DIFFSTAT 1
+#define MERGE_SHOW_COMPACTSUMMARY 2
+
+static int show_diffstat = MERGE_SHOW_DIFFSTAT, shortlog_len = -1, squash;
 static int option_commit = -1;
 static int option_edit = -1;
 static int allow_trivial = 1, have_message, verify_signatures;
@@ -243,12 +246,28 @@ static int option_parse_strategy(const struct option *opt UNUSED,
 	return 0;
 }
 
+static int option_parse_compact_summary(const struct option *opt,
+					const char *name UNUSED, int unset)
+{
+	int *setting = opt->value;
+
+	if (unset)
+		*setting = 0;
+	else
+		*setting = MERGE_SHOW_COMPACTSUMMARY;
+	return 0;
+}
+
 static struct option builtin_merge_options[] = {
 	OPT_SET_INT('n', NULL, &show_diffstat,
 		N_("do not show a diffstat at the end of the merge"), 0),
 	OPT_BOOL(0, "stat", &show_diffstat,
 		N_("show a diffstat at the end of the merge")),
 	OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
+	OPT_CALLBACK_F(0, "compact-summary", &show_diffstat, N_("compact-summary"),
+		       N_("show a compactstat at the end of the merge"),
+		       PARSE_OPT_NOARG,
+		       option_parse_compact_summary),
 	{
 		.type = OPTION_INTEGER,
 		.long_name = "log",
@@ -494,8 +513,19 @@ static void finish(struct commit *head_commit,
 		struct diff_options opts;
 		repo_diff_setup(the_repository, &opts);
 		init_diffstat_widths(&opts);
-		opts.output_format |=
-			DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
+
+		switch (show_diffstat) {
+		case MERGE_SHOW_DIFFSTAT: /* 1 */
+			opts.output_format |=
+				DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
+			break;
+		case MERGE_SHOW_COMPACTSUMMARY: /* 2 */
+			opts.output_format |= DIFF_FORMAT_DIFFSTAT;
+			opts.flags.stat_with_summary = 1;
+			break;
+		default:
+			break;
+		}
 		opts.detect_rename = DIFF_DETECT_RENAME;
 		diff_setup_done(&opts);
 		diff_tree_oid(head, new_head, "", &opts);
@@ -643,7 +673,8 @@ static int git_merge_config(const char *k, const char *v,
 	}
 
 	if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat")) {
-		show_diffstat = git_config_bool(k, v);
+		show_diffstat = git_config_bool(k, v)
+			? MERGE_SHOW_DIFFSTAT : 0;
 	} else if (!strcmp(k, "merge.verifysignatures")) {
 		verify_signatures = git_config_bool(k, v);
 	} else if (!strcmp(k, "pull.twohead")) {
diff --git a/builtin/pull.c b/builtin/pull.c
index a1ebc6ad33..6e72a2e9a4 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -143,6 +143,9 @@ static struct option pull_options[] = {
 	OPT_PASSTHRU(0, "summary", &opt_diffstat, NULL,
 		N_("(synonym to --stat)"),
 		PARSE_OPT_NOARG | PARSE_OPT_HIDDEN),
+	OPT_PASSTHRU(0, "compact-summary", &opt_diffstat, NULL,
+		N_("show a compact-summary at the end of the merge"),
+		PARSE_OPT_NOARG),
 	OPT_PASSTHRU(0, "log", &opt_log, N_("n"),
 		N_("add (at most <n>) entries from shortlog to merge commit message"),
 		PARSE_OPT_OPTARG),
diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh
index 2a8df29219..ce666efbcc 100755
--- a/t/t7600-merge.sh
+++ b/t/t7600-merge.sh
@@ -185,8 +185,19 @@ test_expect_success 'reject non-strategy with a git-merge-foo name' '
 test_expect_success 'merge c0 with c1' '
 	echo "OBJID HEAD@{0}: merge c1: Fast-forward" >reflog.expected &&
 
+	cat >expect <<-EOF &&
+	Updating FROM..TO
+	Fast-forward
+	 file  | 2 +-
+	 other | 9 +++++++++
+	 2 files changed, 10 insertions(+), 1 deletion(-)
+	 create mode 100644 other
+	EOF
+
 	git reset --hard c0 &&
-	git merge c1 &&
+	git merge c1 >out &&
+	sed -e "1s/^Updating [0-9a-f.]*/Updating FROM..TO/" out >actual &&
+	test_cmp expect actual &&
 	verify_merge file result.1 &&
 	verify_head "$c1" &&
 
@@ -205,6 +216,21 @@ test_expect_success 'merge c0 with c1 with --ff-only' '
 	verify_head "$c1"
 '
 
+test_expect_success 'the same merge with compact summary' '
+	cat >expect <<-EOF &&
+	Updating FROM..TO
+	Fast-forward
+	 file        | 2 +-
+	 other (new) | 9 +++++++++
+	 2 files changed, 10 insertions(+), 1 deletion(-)
+	EOF
+
+	git reset --hard c0 &&
+	git merge --compact-summary c1 >out &&
+	sed -e "1s/^Updating [0-9a-f.]*/Updating FROM..TO/" out >actual &&
+	test_cmp expect actual
+'
+
 test_debug 'git log --graph --decorate --oneline --all'
 
 test_expect_success 'merge from unborn branch' '
-- 
2.50.0-rc1-276-gda78c2366e

Re: [PATCH] merge/pull: --compact-summary

[D. Ben Knoble]

On Sun, Jun 8, 2025 at 12:06 PM Junio C Hamano <gitster@pobox.com> wrote:
>
> By default, "git merge" and "git pull" shows "git diff --stat @{1}"
> to show the extent of the changes.  While it gives a good overview,
> one thing that is missing in this output is which paths are created
> and/or deleted.
>
> Introduce "--compact-summary" option to these two commands that
> tells it to instead show "git diff --compact-summary @{1}", which
> gives the same diffstat but notes the created or deleted paths.

Does this suggest that we either want a "diff options" option (or
config), which would be more general? Or perhaps that the intended
workflow if you want a compact summary is instead

    git [merge|pull] …
    git diff --compact-summary HEAD^

?

(The code seems reasonable, just wondering about the motivation/workflow.)

>
> Signed-off-by: Junio C Hamano <gitster@pobox.com>
> ---
>  Documentation/git-merge.adoc     |  2 +-
>  Documentation/merge-options.adoc |  3 +++
>  builtin/merge.c                  | 39 ++++++++++++++++++++++++++++----
>  builtin/pull.c                   |  3 +++
>  t/t7600-merge.sh                 | 28 ++++++++++++++++++++++-
>  5 files changed, 69 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/git-merge.adoc b/Documentation/git-merge.adoc
> index 12aa859d16..d53923c3b7 100644
> --- a/Documentation/git-merge.adoc
> +++ b/Documentation/git-merge.adoc
> @@ -9,7 +9,7 @@ git-merge - Join two or more development histories together
>  SYNOPSIS
>  --------
>  [synopsis]
> -git merge [-n] [--stat] [--no-commit] [--squash] [--[no-]edit]
> +git merge [-n] [--stat] [--compact-summary] [--no-commit] [--squash] [--[no-]edit]
>         [--no-verify] [-s <strategy>] [-X <strategy-option>] [-S[<keyid>]]
>         [--[no-]allow-unrelated-histories]
>         [--[no-]rerere-autoupdate] [-m <msg>] [-F <file>]
> diff --git a/Documentation/merge-options.adoc b/Documentation/merge-options.adoc
> index 078f4f6157..95ef491be1 100644
> --- a/Documentation/merge-options.adoc
> +++ b/Documentation/merge-options.adoc
> @@ -113,6 +113,9 @@ include::signoff-option.adoc[]
>  With `-n` or `--no-stat` do not show a diffstat at the end of the
>  merge.
>
> +`--compact-summary`::
> +       Show a compact-summary at the end of the merge.
> +
>  `--squash`::
>  `--no-squash`::
>         Produce the working tree and index state as if a real merge
> diff --git a/builtin/merge.c b/builtin/merge.c
> index ce90e52fe4..736739d3a9 100644
> --- a/builtin/merge.c
> +++ b/builtin/merge.c
> @@ -69,7 +69,10 @@ static const char * const builtin_merge_usage[] = {
>         NULL
>  };
>
> -static int show_diffstat = 1, shortlog_len = -1, squash;
> +#define MERGE_SHOW_DIFFSTAT 1
> +#define MERGE_SHOW_COMPACTSUMMARY 2
> +
> +static int show_diffstat = MERGE_SHOW_DIFFSTAT, shortlog_len = -1, squash;
>  static int option_commit = -1;
>  static int option_edit = -1;
>  static int allow_trivial = 1, have_message, verify_signatures;
> @@ -243,12 +246,28 @@ static int option_parse_strategy(const struct option *opt UNUSED,
>         return 0;
>  }
>
> +static int option_parse_compact_summary(const struct option *opt,
> +                                       const char *name UNUSED, int unset)
> +{
> +       int *setting = opt->value;
> +
> +       if (unset)
> +               *setting = 0;
> +       else
> +               *setting = MERGE_SHOW_COMPACTSUMMARY;
> +       return 0;
> +}
> +
>  static struct option builtin_merge_options[] = {
>         OPT_SET_INT('n', NULL, &show_diffstat,
>                 N_("do not show a diffstat at the end of the merge"), 0),
>         OPT_BOOL(0, "stat", &show_diffstat,
>                 N_("show a diffstat at the end of the merge")),
>         OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
> +       OPT_CALLBACK_F(0, "compact-summary", &show_diffstat, N_("compact-summary"),
> +                      N_("show a compactstat at the end of the merge"),
> +                      PARSE_OPT_NOARG,
> +                      option_parse_compact_summary),
>         {
>                 .type = OPTION_INTEGER,
>                 .long_name = "log",
> @@ -494,8 +513,19 @@ static void finish(struct commit *head_commit,
>                 struct diff_options opts;
>                 repo_diff_setup(the_repository, &opts);
>                 init_diffstat_widths(&opts);
> -               opts.output_format |=
> -                       DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
> +
> +               switch (show_diffstat) {
> +               case MERGE_SHOW_DIFFSTAT: /* 1 */
> +                       opts.output_format |=
> +                               DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
> +                       break;
> +               case MERGE_SHOW_COMPACTSUMMARY: /* 2 */
> +                       opts.output_format |= DIFF_FORMAT_DIFFSTAT;
> +                       opts.flags.stat_with_summary = 1;
> +                       break;
> +               default:
> +                       break;
> +               }
>                 opts.detect_rename = DIFF_DETECT_RENAME;
>                 diff_setup_done(&opts);
>                 diff_tree_oid(head, new_head, "", &opts);
> @@ -643,7 +673,8 @@ static int git_merge_config(const char *k, const char *v,
>         }
>
>         if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat")) {
> -               show_diffstat = git_config_bool(k, v);
> +               show_diffstat = git_config_bool(k, v)
> +                       ? MERGE_SHOW_DIFFSTAT : 0;
>         } else if (!strcmp(k, "merge.verifysignatures")) {
>                 verify_signatures = git_config_bool(k, v);
>         } else if (!strcmp(k, "pull.twohead")) {
> diff --git a/builtin/pull.c b/builtin/pull.c
> index a1ebc6ad33..6e72a2e9a4 100644
> --- a/builtin/pull.c
> +++ b/builtin/pull.c
> @@ -143,6 +143,9 @@ static struct option pull_options[] = {
>         OPT_PASSTHRU(0, "summary", &opt_diffstat, NULL,
>                 N_("(synonym to --stat)"),
>                 PARSE_OPT_NOARG | PARSE_OPT_HIDDEN),
> +       OPT_PASSTHRU(0, "compact-summary", &opt_diffstat, NULL,
> +               N_("show a compact-summary at the end of the merge"),
> +               PARSE_OPT_NOARG),
>         OPT_PASSTHRU(0, "log", &opt_log, N_("n"),
>                 N_("add (at most <n>) entries from shortlog to merge commit message"),
>                 PARSE_OPT_OPTARG),
> diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh
> index 2a8df29219..ce666efbcc 100755
> --- a/t/t7600-merge.sh
> +++ b/t/t7600-merge.sh
> @@ -185,8 +185,19 @@ test_expect_success 'reject non-strategy with a git-merge-foo name' '
>  test_expect_success 'merge c0 with c1' '
>         echo "OBJID HEAD@{0}: merge c1: Fast-forward" >reflog.expected &&
>
> +       cat >expect <<-EOF &&
> +       Updating FROM..TO
> +       Fast-forward
> +        file  | 2 +-
> +        other | 9 +++++++++
> +        2 files changed, 10 insertions(+), 1 deletion(-)
> +        create mode 100644 other
> +       EOF
> +
>         git reset --hard c0 &&
> -       git merge c1 &&
> +       git merge c1 >out &&
> +       sed -e "1s/^Updating [0-9a-f.]*/Updating FROM..TO/" out >actual &&
> +       test_cmp expect actual &&
>         verify_merge file result.1 &&
>         verify_head "$c1" &&
>
> @@ -205,6 +216,21 @@ test_expect_success 'merge c0 with c1 with --ff-only' '
>         verify_head "$c1"
>  '
>
> +test_expect_success 'the same merge with compact summary' '
> +       cat >expect <<-EOF &&
> +       Updating FROM..TO
> +       Fast-forward
> +        file        | 2 +-
> +        other (new) | 9 +++++++++
> +        2 files changed, 10 insertions(+), 1 deletion(-)
> +       EOF
> +
> +       git reset --hard c0 &&
> +       git merge --compact-summary c1 >out &&
> +       sed -e "1s/^Updating [0-9a-f.]*/Updating FROM..TO/" out >actual &&
> +       test_cmp expect actual
> +'
> +
>  test_debug 'git log --graph --decorate --oneline --all'
>
>  test_expect_success 'merge from unborn branch' '
> --
> 2.50.0-rc1-276-gda78c2366e
>
>


-- 
D. Ben Knoble

Re: [PATCH] merge/pull: --compact-summary

[Junio C Hamano]

"D. Ben Knoble" <ben.knoble@gmail.com> writes:

> Does this suggest that we either want a "diff options" option (or
> config), which would be more general?

If I have bk/new-topic branch, here is how I would merge it.

    $ git merge --compact-summary bk/new-topic

but there is an existing merge.stat that (1) is a mere boolean and
(2) is true by default to force use of "--stat" option.  We could
extend it to "bool or the string 'compact-summary'" and when it is

 - not set, do the "--stat" as before;
 - set to true, do the "--stat" as before;
 - set to 'compact-summary', do the "--compact-summary".

With such a configuration variable, "git merge bk/new-topic" would
be how I would run my merge.

[PATCH 2/1] merge/pull: extend merge.stat configuration variable to cover --compact-summary

[Junio C Hamano]

Existing `merge.stat` configuration variable is a Boolean that
defaults to `true` to control `git merge --[no-]stat` behaviour.

Extend it to be "Boolean or text", that takes false, true, or
"compact", with the last one triggering the --compact-summary
option introduced earlier.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

 * "git merge --(summary|stat)[=true/false/compact]" is a
   possibility on the command line options side, but options with
   optional values are generally frowned upon, so [1/1] is unchanged
   and introduces a new --compact-summary option.

 Documentation/config/merge.adoc | 12 ++++++++++--
 builtin/merge.c                 | 18 ++++++++++++++++--
 t/t7600-merge.sh                | 15 +++++++++++++++
 3 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/Documentation/config/merge.adoc b/Documentation/config/merge.adoc
index 86359f6dd2..251a48fdf8 100644
--- a/Documentation/config/merge.adoc
+++ b/Documentation/config/merge.adoc
@@ -81,8 +81,16 @@ as `false`. Defaults to `conflict`.
 	attributes" in linkgit:gitattributes[5].
 
 `merge.stat`::
-	Whether to print the diffstat between `ORIG_HEAD` and the merge result
-	at the end of the merge.  True by default.
+	What, if anything, to print between `ORIG_HEAD` and the merge result
+	at the end of the merge.  Possible values are:
++
+--
+`false`;; Show nothing.
+`true`;; Show `git diff --diffstat ORIG_HEAD`.
+`compact`;; Show `git diff --compact-summary ORIG_HEAD`.
+--
++
+If this variable is left unspecified, it defaults to `true`.
 
 `merge.autoStash`::
 	When set to `true`, automatically create a temporary stash entry
diff --git a/builtin/merge.c b/builtin/merge.c
index 736739d3a9..65fed4b687 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -673,8 +673,22 @@ static int git_merge_config(const char *k, const char *v,
 	}
 
 	if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat")) {
-		show_diffstat = git_config_bool(k, v)
-			? MERGE_SHOW_DIFFSTAT : 0;
+		int val = git_parse_maybe_bool_text(v);
+		switch (val) {
+		case 0:
+			show_diffstat = 0;
+			break;
+		case 1:
+			show_diffstat = MERGE_SHOW_DIFFSTAT;
+			break;
+		default:
+			if (!strcmp(v, "compact"))
+				show_diffstat = MERGE_SHOW_COMPACTSUMMARY;
+			else
+				/* setting from the future -- use the default */
+				show_diffstat = MERGE_SHOW_DIFFSTAT;
+			break;
+		}
 	} else if (!strcmp(k, "merge.verifysignatures")) {
 		verify_signatures = git_config_bool(k, v);
 	} else if (!strcmp(k, "pull.twohead")) {
diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh
index ce666efbcc..95842188e3 100755
--- a/t/t7600-merge.sh
+++ b/t/t7600-merge.sh
@@ -231,6 +231,21 @@ test_expect_success 'the same merge with compact summary' '
 	test_cmp expect actual
 '
 
+test_expect_success 'the same merge with merge.stat=compact' '
+	cat >expect <<-EOF &&
+	Updating FROM..TO
+	Fast-forward
+	 file        | 2 +-
+	 other (new) | 9 +++++++++
+	 2 files changed, 10 insertions(+), 1 deletion(-)
+	EOF
+
+	git reset --hard c0 &&
+	git -c merge.stat=compact merge c1 >out &&
+	sed -e "1s/^Updating [0-9a-f.]*/Updating FROM..TO/" out >actual &&
+	test_cmp expect actual
+'
+
 test_debug 'git log --graph --decorate --oneline --all'
 
 test_expect_success 'merge from unborn branch' '
-- 
2.50.0-rc2-207-gc448ca4963

Re: [PATCH 2/1] merge/pull: extend merge.stat configuration variable to cover --compact-summary

[Eric Sunshine]

On Wed, Jun 11, 2025 at 1:00 PM Junio C Hamano <gitster@pobox.com> wrote:
> Existing `merge.stat` configuration variable is a Boolean that
> defaults to `true` to control `git merge --[no-]stat` behaviour.
>
> Extend it to be "Boolean or text", that takes false, true, or
> "compact", with the last one triggering the --compact-summary
> option introduced earlier.
>
> Signed-off-by: Junio C Hamano <gitster@pobox.com>
> ---
> diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh
> @@ -231,6 +231,21 @@ test_expect_success 'the same merge with compact summary' '
> +test_expect_success 'the same merge with merge.stat=compact' '
> +       cat >expect <<-EOF &&

Do we want \EOF (with backslash)?

> +       Updating FROM..TO
> +       Fast-forward
> +        file        | 2 +-
> +        other (new) | 9 +++++++++
> +        2 files changed, 10 insertions(+), 1 deletion(-)
> +       EOF
> +
> +       git reset --hard c0 &&
> +       git -c merge.stat=compact merge c1 >out &&
> +       sed -e "1s/^Updating [0-9a-f.]*/Updating FROM..TO/" out >actual &&
> +       test_cmp expect actual
> +'

Re: [PATCH 2/1] merge/pull: extend merge.stat configuration variable to cover --compact-summary

[Junio C Hamano]

Eric Sunshine <sunshine@sunshineco.com> writes:

> Do we want \EOF (with backslash)?
>
>> +       Updating FROM..TO
>> +       Fast-forward
>> +        file        | 2 +-
>> +        other (new) | 9 +++++++++
>> +        2 files changed, 10 insertions(+), 1 deletion(-)
>> +       EOF

Indeed.  There is no interpolation necessary for the contents, so it
is a very good idea to do that.  The same for the test part of
[1/1].

Thanks.

Re: [PATCH] merge/pull: --compact-summary

[D. Ben Knoble]

On Tue, Jun 10, 2025 at 11:12 PM Junio C Hamano <gitster@pobox.com> wrote:
>
> "D. Ben Knoble" <ben.knoble@gmail.com> writes:
>
> > Does this suggest that we either want a "diff options" option (or
> > config), which would be more general?
>
> If I have bk/new-topic branch, here is how I would merge it.
>
>     $ git merge --compact-summary bk/new-topic
>
> but there is an existing merge.stat that (1) is a mere boolean and
> (2) is true by default to force use of "--stat" option.  We could
> extend it to "bool or the string 'compact-summary'" and when it is
>
>  - not set, do the "--stat" as before;
>  - set to true, do the "--stat" as before;
>  - set to 'compact-summary', do the "--compact-summary".
>
> With such a configuration variable, "git merge bk/new-topic" would
> be how I would run my merge.

Makes sense; I suppose my question was more along the lines of "should
we go ahead and support extending the options we give to diff more
broadly rather than add a one-off flag (and potentially add more
later)."

-- 
D. Ben Knoble