From 6393ec8118e7f5481ab476c2d73614c89c64866f Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Wed, 15 Sep 2021 21:35:55 +0000
Subject: fetch: support --exit-code switch

As noted in the new manpage entry, this is useful for avoiding
public-inbox-index invocations when there's nothing to update.
We use 127 to match "grok-pull", and also because it doesn't
conflict with any of the current curl(1) exit codes.
---
 Documentation/public-inbox-fetch.pod | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

(limited to 'Documentation/public-inbox-fetch.pod')

diff --git a/Documentation/public-inbox-fetch.pod b/Documentation/public-inbox-fetch.pod
index 7944fdcd..28d5638d 100644
--- a/Documentation/public-inbox-fetch.pod
+++ b/Documentation/public-inbox-fetch.pod
@@ -4,7 +4,7 @@ public-inbox-fetch - "git fetch" wrapper for v2 inbox mirrors
 
 =head1 SYNOPSIS
 
-public-inbox-fetch -C INBOX_DIR
+public-inbox-fetch [--exit-code] -C INBOX_DIR
 
 =head1 DESCRIPTION
 
@@ -31,6 +31,15 @@ file to speed up future invocations.
 
 Quiets down progress messages, also passed to L<git-fetch(1)>.
 
+=item --exit-code
+
+Exit with C<127> if no updates are done.  This can be used in
+shell scripts to avoid invoking L<public-inbox-index(1)> when
+there are no updates:
+
+	public-inbox-fetch -q --exit-code && public-inbox-index
+	test $? -eq 0 || exit $?
+
 =item -v
 
 =item --verbose
@@ -45,6 +54,23 @@ Whether to wrap L<git(1)> and L<curl(1)> commands with torsocks.
 
 Default: C<auto>
 
+=back
+
+=head1 EXIT CODES
+
+=over
+
+=item 127
+
+no updates when L</--exit-code> is used above
+
+=back
+
+public-inbox-fetch will also exit with curl L<curl(1)/EXIT CODES>
+as documented in the L<curl(1)> manpage (e.g. C<7> when curl cannot
+reach a host).  Likewise, L<git-fetch(1)> failures are also
+propagated to the user.
+
 =head1 CONTACT
 
 Feedback welcome via plain-text mail to L<mailto:meta@public-inbox.org>
@@ -60,4 +86,4 @@ License: AGPL-3.0+ L<https://www.gnu.org/licenses/agpl-3.0.txt>
 
 =head1 SEE ALSO
 
-L<public-inbox-index(1)>
+L<public-inbox-index(1)>, L<curl(1)>
-- 
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