[PATCH v2] git-contacts: allow inputting patch via stdin

From

Brigham Campbell <me@brighamcampbell.com>

Date

Sep 16, 2026, 04:52 UTC

Message-ID

<20260915-git-contacts-stdin-v2-1-2005061d907a@brighamcampbell.com>

In-Reply-To

<20260914-git-contacts-stdin-v1-1-9ac628e6fd20@brighamcampbell.com>

* stdin is not a terminal
* argv is empty

Signed-off-by: Brigham Campbell <me@brighamcampbell.com>
---
I authored this patch as the first of a two-patch series to enable b4 to
automatically determine patch recipients. The second patch modifies
.b4-config to wire everything up. I discovered, however, that the latest
version of b4 doesn't pass the mbox "Fixes " header as it should. A fix
is queued for the next release of b4.

Link: https://lore.kernel.org/tools/20260914-mbox-from-auto-to-cc-v1-1-fbf0c3fbd460@brighamcampbell.com
---
Changes in v2 (Thanks for your careful review, Junio):
- Minor variable cleanup / un-spaghettification
- Include update to usage comment
- Remove Cc trailers from commit message
- Link to v1: https://patch.msgid.link/20260914-git-contacts-stdin-v1-1-9ac628e6fd20@brighamcampbell.com
---
 contrib/contacts/git-contacts | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/contrib/contacts/git-contacts b/contrib/contacts/git-contacts
index 85ad732fc0..03d03135d6 100755
--- a/contrib/contacts/git-contacts
+++ b/contrib/contacts/git-contacts
@@ -4,6 +4,7 @@
 # git-send-email --cc-cmd option, and in other situations.
 #
 # Usage: git contacts <file | rev-list option> ...
+#        git contacts < <patch>
 
 use strict;
 use warnings;
@@ -158,11 +159,15 @@ sub mailmap_contacts {
 	return \%mapped;
 }
 
+my (@files, @rev_args, $read_from_stdin);
+
 if (!@ARGV) {
-	die "No input revisions or patch files\n";
+	if (-t STDIN) {
+		die "No input revisions or patch files\n";
+	}
+	$read_from_stdin = 1;
 }
 
-my (@files, @rev_args);
 for (@ARGV) {
 	if (-e) {
 		push @files, $_;
@@ -178,6 +183,9 @@ for (@files) {
 if (@rev_args) {
 	scan_rev_args(\%sources, \@rev_args)
 }
+if ($read_from_stdin) {
+	scan_patches(\%sources, undef, \*STDIN);
+}
 
 my $toplevel = `git rev-parse --show-toplevel`;
 chomp $toplevel;

---
base-commit: f0ef1b96a076d08dc972a8d2cb0d1cfd60931eb6
change-id: 20260914-git-contacts-stdin-1e829930e19b

Thanks!

-- 
Brigham Campbell
https://brighamcampbell.com