lei_mirror: further reduce `git config' calls

We can parse the config at once and avoid clobbering variables
which do not need changing.  We'll also do some prep work for
fetch.hideRefs proposal being discussed at
<https://public-inbox.org/git/20230209122857.M669733@dcvr/>

diff --git a/lib/PublicInbox/LeiMirror.pm b/lib/PublicInbox/LeiMirror.pm
index d959b6b61ac4cd018b1142681d663261846596b6..dd6356bbc340d8fc754d781148351c5ce7a32c14 100644 (file)
--- a/lib/PublicInbox/LeiMirror.pm
+++ b/lib/PublicInbox/LeiMirror.pm
@@ -401,23 +401,42 @@ sub fgrp_fetch_all {
        my $opt = {};
        my @fetch = do {
                local $self->{lei}->{opt}->{jobs} = 1;
-               (fetch_args($self->{lei}, $opt),
-                       qw(--no-tags --multiple));
+               (fetch_args($self->{lei}, $opt), qw(--no-tags --multiple));
        };
        push(@fetch, "-j$j") if $j;
        while (my ($osdir, $fgrpv) = each %$todo) {
                my $f = "$osdir/config";
                return if !keep_going($self);
 
+               my $cmd = ['git', "--git-dir=$osdir", qw(config -f), $f ];
                # clobber group from previous run atomically
-               my $cmd = ['git', "--git-dir=$osdir", qw(config -f),
-                               $f, '--unset-all', "remotes.$grp"];
-               $self->{lei}->qerr("# @$cmd");
-               if (!$self->{dry_run}) {
-                       my $pid = spawn($cmd, undef, { 2 => $self->{lei}->{2} });
+               for ("remotes.$grp") { # TODO: hideRefs
+                       my $c = [ @$cmd, '--unset-all', $_ ];
+                       $self->{lei}->qerr("# @$c");
+                       next if $self->{dry_run};
+                       my $pid = spawn($c, undef, $opt);
                        waitpid($pid, 0) // die "waitpid: $!";
-                       die "E: @$cmd: \$?=$?" if ($? && ($? >> 8) != 5);
+                       die "E: @$c \$?=$?" if ($? && ($? >> 8) != 5);
+               }
 
+               # permanent configs:
+               my $cfg = PublicInbox::Config->git_config_dump($f);
+               for my $fgrp (@$fgrpv) {
+                       my $u = $fgrp->{-uri} // die 'BUG: no {-uri}';
+                       my $rn = $fgrp->{-remote} // die 'BUG: no {-remote}';
+                       for ("url=$u", "fetch=+refs/*:refs/remotes/$rn/*",
+                                       'tagopt=--no-tags') {
+                               my ($k, $v) = split(/=/, $_, 2);
+                               $k = "remote.$rn.$k";
+                               next if ($cfg->{$k} // '') eq $v;
+                               my $c = [@$cmd, $k, $v];
+                               $fgrp->{lei}->qerr("# @$c");
+                               next if $fgrp->{dry_run};
+                               run_die($c, undef, $opt);
+                       }
+               }
+
+               if (!$self->{dry_run}) {
                        # update the config atomically via O_APPEND while
                        # respecting git-config locking
                        sysopen(my $lk, "$f.lock", O_CREAT|O_EXCL|O_WRONLY)
@@ -430,7 +449,6 @@ sub fgrp_fetch_all {
                        close $fh or die "close($f): $!";
                        unlink("$f.lock") or die "unlink($f.lock): $!";
                }
-
                $cmd = [ @git, "--git-dir=$osdir", @fetch, $grp ];
                my $end = PublicInbox::OnDestroy->new($$, \&fgrpv_done, $fgrpv);
                start_cmd($self, $cmd, $opt, $end);
@@ -446,12 +464,15 @@ sub forkgroup_prep {
        my $dir = "$os/$fg.git";
        if (!-d $dir && !$self->{dry_run}) {
                PublicInbox::Import::init_bare($dir);
-               my @cmd = ('git', "--git-dir=$dir", 'config');
-               my $opt = { 2 => $self->{lei}->{2} };
-               for ('repack.useDeltaIslands=true',
-                               'pack.island=refs/remotes/([^/]+)/') {
-                       run_die([@cmd, split(/=/, $_, 2)], undef, $opt);
-               }
+               my $f = "$dir/config";
+               open my $fh, '+>>', $f or die "open:($f): $!";
+               print $fh <<EOM or die "print($f): $!";
+[repack]
+       useDeltaIslands = true
+[pack]
+       island = refs/remotes/([^/]+)/
+EOM
+               close $fh or die "close($f): $!";
        }
        my $key = $self->{-key} // die 'BUG: no -key';
        my $rn = substr(sha256_hex($key), 0, 16);
@@ -546,17 +567,6 @@ sub resume_fetch {
 sub fgrp_enqueue {
        my ($fgrp, $end) = @_; # $end calls fgrp_fetch_all
        return if !keep_going($fgrp);
-       my $opt = { 2 => $fgrp->{lei}->{2} };
-       # --no-tags is required to avoid conflicts
-       my $u = $fgrp->{-uri} // die 'BUG: no {-uri}';
-       my $rn = $fgrp->{-remote} // die 'BUG: no {-remote}';
-       my @cmd = ('git', "--git-dir=$fgrp->{-osdir}", 'config');
-       for ("url=$u", "fetch=+refs/*:refs/remotes/$rn/*", 'tagopt=--no-tags') {
-               my @kv = split(/=/, $_, 2);
-               $kv[0] = "remote.$rn.$kv[0]";
-               $fgrp->{dry_run} ? $fgrp->{lei}->qerr("# @cmd @kv") :
-                               run_die([@cmd, @kv], undef, $opt);
-       }
        ++$fgrp->{chg}->{nr_chg};
        push @{$FGRP_TODO->{$fgrp->{-osdir}}}, $fgrp;
 }