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

From: Brigham Campbell <me@brighamcampbell.com>
Date: Sep 15, 2026, 02:43 UTC
Message-ID: <20260914-git-contacts-stdin-v1-1-9ac628e6fd20@brighamcampbell.com>

Make git-contacts accept patch contents via stdin for better interoperability with other utilities. Read from stdin under the following circumstances:

* stdin is not a terminal
* argv is empty

Cc: Junio C Hamano <gitster@pobox.com>
Cc: Patrick Steinhardt <ps@pks.im>
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 b4 doesn't
yet pass the mbox "Fixes " header as it should. I sent a fix to b4.

The second patch of this series will therefore have to wait until the b4 fix lands in the latest version, so I'm splitting up this series of patches to git. This patch is useful and warranted even by itself.

Link: https://lore.kernel.org/tools/20260914-mbox-from-auto-to-cc-v1-1-fbf0c3fbd460@brighamcampbell.com
---
 contrib/contacts/git-contacts | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/contrib/contacts/git-contacts b/contrib/contacts/git-contacts
index 85ad732fc0..52f6fbd044 100755
--- a/contrib/contacts/git-contacts
+++ b/contrib/contacts/git-contacts
@@ -158,7 +158,7 @@ sub mailmap_contacts {
 	return \%mapped;
 }
 
-if (!@ARGV) {
+if (!@ARGV && -t STDIN) {
 	die "No input revisions or patch files\n";
 }
 
@@ -178,6 +178,9 @@ for (@files) {
 if (@rev_args) {
 	scan_rev_args(\%sources, \@rev_args)
 }
+if (!@ARGV) {
+	scan_patches(\%sources, undef, \*STDIN);
+}
 
 my $toplevel = `git rev-parse --show-toplevel`;
 chomp $toplevel;

---
base-commit: 47ce80527c56f462cb97db4ca8125342204d3783
change-id: 20260914-git-contacts-stdin-1e829930e19b

Thanks!

-- 
Brigham Campbell
https://brighamcampbell.com