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.
---
 lib/PublicInbox/Fetch.pm | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

(limited to 'lib/PublicInbox/Fetch.pm')

diff --git a/lib/PublicInbox/Fetch.pm b/lib/PublicInbox/Fetch.pm
index 9ea55e9d..0539fe50 100644
--- a/lib/PublicInbox/Fetch.pm
+++ b/lib/PublicInbox/Fetch.pm
@@ -75,12 +75,22 @@ sub do_manifest ($$$) {
 		my $t1 = $cur->{modified} // next;
 		delete($mdiff->{$k}) if $f0 eq $f1 && $t0 == $t1;
 	}
-	return unless keys %$mdiff;
+	unless (keys %$mdiff) {
+		$lei->child_error(127 << 8) if $lei->{opt}->{'exit-code'};
+		return;
+	}
 	my (undef, $v1_path, @v2_epochs) =
 		PublicInbox::LeiMirror::deduce_epochs($mdiff, $ibx_uri->path);
 	[ 200, $v1_path, \@v2_epochs, $muri, $ft, $mf ];
 }
 
+sub get_fingerprint2 {
+	my ($git_dir) = @_;
+	require Digest::SHA;
+	my $rd = popen_rd([qw(git show-ref)], undef, { -C => $git_dir });
+	Digest::SHA::sha256(do { local $/; <$rd> });
+}
+
 sub do_fetch {
 	my ($cls, $lei, $cd) = @_;
 	my $ibx_ver;
@@ -136,11 +146,14 @@ EOM
 	}
 	# n.b. this expects all epochs are from the same host
 	my $torsocks = $lei->{curl}->torsocks($lei, $muri);
+	my $fp2 = $lei->{opt}->{'exit-code'} ? [] : undef;
+	my $xit = 127;
 	for my $d (@git_dir) {
 		my $cmd;
 		my $opt = {}; # for spawn
 		if (-d $d) {
 			$opt->{-C} = $d;
+			$fp2->[0] = get_fingerprint2($d) if $fp2;
 			$cmd = [ @$torsocks, fetch_cmd($lei, $opt) ];
 		} else {
 			my $e_uri = $ibx_uri->clone;
@@ -152,6 +165,7 @@ EOM
 				PublicInbox::LeiMirror::clone_cmd($lei, $opt),
 				$$e_uri, $d];
 			push @new_epoch, substr($epath, 5, -4) + 0;
+			$xit = 0;
 		}
 		my $cerr = PublicInbox::LeiMirror::run_reap($lei, $cmd, $opt);
 		# do not bail on clone failure if we didn't have a manifest
@@ -159,6 +173,10 @@ EOM
 			$lei->child_error($cerr, "@$cmd failed");
 			return;
 		}
+		if ($fp2 && $xit) {
+			$fp2->[1] = get_fingerprint2($d);
+			$xit = 0 if $fp2->[0] ne $fp2->[1];
+		}
 	}
 	for my $i (@new_epoch) { $mg->epoch_cfg_set($i) }
 	if ($ft) {
@@ -166,6 +184,7 @@ EOM
 		rename($fn, $mf) or die "E: rename($fn, $mf): $!\n";
 		$ft->unlink_on_destroy(0);
 	}
+	$lei->child_error($xit << 8) if $fp2 && $xit;
 }
 
 1;
-- 
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