[PATCH 1/3] lei: fix handling of broken lei.saved-search config files

[Eric Wong <e@80x24.org>]

lei shouldn't become unusable if a config file is invalid.
Instead, show the "git config" stderr and attempt to continue
gracefully.

Reported-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
Link: https://public-inbox.org/meta/20210910141157.6u5adehpx7wftkor@meerkat.local/
---
 lib/PublicInbox/Config.pm         |  6 +--
 lib/PublicInbox/LEI.pm            | 21 ++++++--
 lib/PublicInbox/LeiEditSearch.pm  | 79 +++++++++++++++++++++++++++++--
 lib/PublicInbox/LeiSavedSearch.pm | 77 ++++++------------------------
 script/lei                        |  2 +
 t/lei-q-save.t                    | 17 +++++++
 6 files changed, 128 insertions(+), 74 deletions(-)

diff --git a/lib/PublicInbox/Config.pm b/lib/PublicInbox/Config.pm
index b3e00ae0..74a1a6f5 100644
--- a/lib/PublicInbox/Config.pm
+++ b/lib/PublicInbox/Config.pm
@@ -164,12 +164,12 @@ sub config_fh_parse ($$$) {
 }
 
 sub git_config_dump {
-	my ($class, $file) = @_;
+	my ($class, $file, $errfh) = @_;
 	return bless {}, $class unless -e $file;
 	my $cmd = [ qw(git config -z -l --includes), "--file=$file" ];
-	my $fh = popen_rd($cmd);
+	my $fh = popen_rd($cmd, undef, { 2 => $errfh // 2 });
 	my $rv = config_fh_parse($fh, "\0", "\n");
-	close $fh or die "failed to close (@$cmd) pipe: $?";
+	close $fh or die "@$cmd failed: \$?=$?\n";
 	bless $rv, $class;
 }
 
diff --git a/lib/PublicInbox/LEI.pm b/lib/PublicInbox/LEI.pm
index bbb6ab7e..0b4c99dc 100644
--- a/lib/PublicInbox/LEI.pm
+++ b/lib/PublicInbox/LEI.pm
@@ -1029,13 +1029,15 @@ sub path_to_fd {
 
 # caller needs to "-t $self->{1}" to check if tty
 sub start_pager {
-	my ($self) = @_;
+	my ($self, $new_env) = @_;
 	my $fh = popen_rd([qw(git var GIT_PAGER)]);
 	chomp(my $pager = <$fh> // '');
 	close($fh) or warn "`git var PAGER' error: \$?=$?";
 	return if $pager eq 'cat' || $pager eq '';
-	my $new_env = { LESS => 'FRX', LV => '-c' };
-	$new_env->{MORE} = 'FRX' if $^O eq 'freebsd';
+	$new_env //= {};
+	$new_env->{LESS} //= 'FRX';
+	$new_env->{LV} //= '-c';
+	$new_env->{MORE} = $new_env->{LESS} if $^O eq 'freebsd';
 	pipe(my ($r, $wpager)) or return warn "pipe: $!";
 	my $rdr = { 0 => $r, 1 => $self->{1}, 2 => $self->{2} };
 	my $pgr = [ undef, @$rdr{1, 2} ];
@@ -1052,6 +1054,19 @@ sub start_pager {
 	$self->{pgr} = $pgr;
 }
 
+# display a message for user before spawning full-screen $VISUAL
+sub pgr_err {
+	my ($self, @msg) = @_;
+	return $self->err(@msg) unless $self->{sock} && -t $self->{2};
+	start_pager($self, { LESS => 'RX' }); # no 'F' so we prompt
+	print { $self->{2} } @msg;
+	$self->{2}->autoflush(1);
+	my $pgr = delete($self->{pgr}) or return;
+	$self->{2} = $pgr->[2];
+	$self->{1} = $pgr->[1];
+	send($self->{sock}, 'wait', MSG_EOR); # wait for user to quit pager
+}
+
 sub stop_pager {
 	my ($self) = @_;
 	my $pgr = delete($self->{pgr}) or return;
diff --git a/lib/PublicInbox/LeiEditSearch.pm b/lib/PublicInbox/LeiEditSearch.pm
index 82dfbf63..47166ce7 100644
--- a/lib/PublicInbox/LeiEditSearch.pm
+++ b/lib/PublicInbox/LeiEditSearch.pm
@@ -8,20 +8,89 @@ use v5.10.1;
 use PublicInbox::LeiSavedSearch;
 use PublicInbox::LeiUp;
 
-sub lei_edit_search {
-	my ($lei, $out) = @_;
-	my $lss = PublicInbox::LeiSavedSearch->up($lei, $out) or return;
+sub edit_begin {
+	my ($lss, $lei) = @_;
+	if (ref($lss->{-cfg}->{'lei.q.output'})) {
+		delete $lss->{-cfg}->{'lei.q.output'}; # invalid
+		$lei->pgr_err(<<EOM);
+$lss->{-f} has multiple values of lei.q.output
+please remove redundant ones
+EOM
+	}
+	$lei->{-lss_for_edit} = $lss;
+}
+
+sub do_edit ($$;$) {
+	my ($lss, $lei, $reason) = @_;
+	$lei->pgr_err($reason) if defined $reason;
 	my @cmd = (qw(git config --edit -f), $lss->{'-f'});
 	$lei->qerr("# spawning @cmd");
-	$lss->edit_begin($lei);
+	edit_begin($lss, $lei);
 	# run in script/lei foreground
 	require PublicInbox::PktOp;
 	my ($op_c, $op_p) = PublicInbox::PktOp->pair;
 	# $op_p will EOF when $EDITOR is done
-	$op_c->{ops} = { '' => [$lss->can('edit_done'), $lss, $lei] };
+	$op_c->{ops} = { '' => [\&op_edit_done, $lss, $lei] };
 	$lei->send_exec_cmd([ @$lei{qw(0 1 2)}, $op_p->{op_p} ], \@cmd, {});
 }
 
+sub _edit_done {
+	my ($lss, $lei) = @_;
+	my $cfg = $lss->can('cfg_dump')->($lei, $lss->{'-f'}) //
+		return do_edit($lss, $lei, <<EOM);
+$lss->{-f} is unparseable
+EOM
+	my $new_out = $cfg->{'lei.q.output'} // '';
+	return do_edit($lss, $lei, <<EOM) if ref $new_out;
+$lss->{-f} has multiple values of lei.q.output
+EOM
+	return do_edit($lss, $lei, <<EOM) if $new_out eq '';
+$lss->{-f} needs lei.q.output
+EOM
+	my $old_out = $lss->{-cfg}->{'lei.q.output'} // return;
+	return if $old_out eq $new_out;
+	my $old_path = $old_out;
+	my $new_path = $new_out;
+	s!$PublicInbox::LeiSavedSearch::LOCAL_PFX!! for ($old_path, $new_path);
+	my $dir_old = $lss->can('lss_dir_for')->($lei, \$old_path, 1);
+	my $dir_new = $lss->can('lss_dir_for')->($lei, \$new_path);
+	return if $dir_new eq $dir_old;
+
+	($old_out =~ m!\Av2:!i || $new_out =~ m!\Av2:!) and
+		return do_edit($lss, $lei, <<EOM);
+conversions from/to v2 inboxes not supported at this time
+EOM
+	return do_edit($lss, $lei, <<EOM) if -e $dir_new;
+lei.q.output changed from `$old_out' to `$new_out'
+However, $dir_new exists
+EOM
+	# start the conversion asynchronously
+	my $old_sq = PublicInbox::Config::squote_maybe($old_out);
+	my $new_sq = PublicInbox::Config::squote_maybe($new_out);
+	$lei->puts("lei.q.output changed from $old_sq to $new_sq");
+	$lei->qerr("# lei convert $old_sq -o $new_sq");
+	my $v = !$lei->{opt}->{quiet};
+	$lei->{opt} = { output => $new_out, verbose => $v };
+	require PublicInbox::LeiConvert;
+	PublicInbox::LeiConvert::lei_convert($lei, $old_out);
+
+	$lei->fail(<<EOM) if -e $dir_old && !rename($dir_old, $dir_new);
+E: rename($dir_old, $dir_new) error: $!
+EOM
+}
+
+sub op_edit_done { # PktOp
+	my ($lss, $lei) = @_;
+	eval { _edit_done($lss, $lei) };
+	$lei->fail($@) if $@;
+}
+
+sub lei_edit_search {
+	my ($lei, $out) = @_;
+	my $lss = PublicInbox::LeiSavedSearch->up($lei, $out) or return;
+	do_edit($lss, $lei);
+}
+
 *_complete_edit_search = \&PublicInbox::LeiUp::_complete_up;
 
 1;
diff --git a/lib/PublicInbox/LeiSavedSearch.pm b/lib/PublicInbox/LeiSavedSearch.pm
index fd51fe38..8ceaaf01 100644
--- a/lib/PublicInbox/LeiSavedSearch.pm
+++ b/lib/PublicInbox/LeiSavedSearch.pm
@@ -14,7 +14,7 @@ use PublicInbox::Spawn qw(run_die);
 use PublicInbox::ContentHash qw(git_sha);
 use PublicInbox::MID qw(mids_for_index);
 use Digest::SHA qw(sha256_hex);
-my $LOCAL_PFX = qr!\A(?:maildir|mh|mbox.+|mmdf|v2):!i; # TODO: put in LeiToMail?
+our $LOCAL_PFX = qr!\A(?:maildir|mh|mbox.+|mmdf|v2):!i; # TODO: put in LeiToMail?
 
 # move this to PublicInbox::Config if other things use it:
 my %cquote = ("\n" => '\\n', "\t" => '\\t', "\b" => '\\b');
@@ -29,6 +29,14 @@ sub BOOL_FIELDS () {
 	qw(external local remote import-remote import-before threads)
 }
 
+sub cfg_dump ($$) {
+	my ($lei, $f) = @_;
+	my $ret = eval { PublicInbox::Config->git_config_dump($f, $lei->{2}) };
+	return $ret if !$@;
+	$lei->err($@);
+	undef;
+}
+
 sub lss_dir_for ($$;$) {
 	my ($lei, $dstref, $on_fs) = @_;
 	my @n;
@@ -56,7 +64,7 @@ sub lss_dir_for ($$;$) {
 		for my $g ("$n[0]-*", '*') {
 			my @maybe = glob("$lss_dir$g/lei.saved-search");
 			for my $f (@maybe) {
-				$c = PublicInbox::Config->git_config_dump($f);
+				$c = cfg_dump($lei, $f) // next;
 				$o = $c->{'lei.q.output'} // next;
 				$o =~ s!$LOCAL_PFX!! or next;
 				@st = stat($o) or next;
@@ -80,9 +88,9 @@ sub list {
 		print $fh "\tpath = ", cquote_val($p), "\n";
 	}
 	close $fh or die "close $f: $!";
-	my $cfg = PublicInbox::Config->git_config_dump($f);
+	my $cfg = cfg_dump($lei, $f);
 	unlink($f);
-	my $out = $cfg->get_all('lei.q.output') or return ();
+	my $out = $cfg ? $cfg->get_all('lei.q.output') : [];
 	map {;
 		s!$LOCAL_PFX!!;
 		$_;
@@ -105,7 +113,7 @@ sub up { # updating existing saved search via "lei up"
 	output2lssdir($self, $lei, \$dir, \$f) or
 		return $lei->fail("--save was not used with $dst cwd=".
 					$lei->rel2abs('.'));
-	$self->{-cfg} = PublicInbox::Config->git_config_dump($f);
+	$self->{-cfg} = cfg_dump($lei, $f) // return $lei->fail;
 	$self->{-ovf} = "$dir/over.sqlite3";
 	$self->{'-f'} = $f;
 	$self->{lock_path} = "$self->{-f}.flock";
@@ -267,7 +275,7 @@ sub output2lssdir {
 	my $dir = lss_dir_for($lei, \$dst, 1);
 	my $f = "$dir/lei.saved-search";
 	if (-f $f && -r _) {
-		$self->{-cfg} = PublicInbox::Config->git_config_dump($f);
+		$self->{-cfg} = cfg_dump($lei, $f) // return;
 		$$dir_ref = $dir;
 		$$fn_ref = $f;
 		return 1;
@@ -275,63 +283,6 @@ sub output2lssdir {
 	undef;
 }
 
-sub edit_begin {
-	my ($self, $lei) = @_;
-	if (ref($self->{-cfg}->{'lei.q.output'})) {
-		delete $self->{-cfg}->{'lei.q.output'}; # invalid
-		$lei->err(<<EOM);
-$self->{-f} has multiple values of lei.q.output
-please remove redundant ones
-EOM
-	}
-	$lei->{-lss_for_edit} = $self;
-}
-
-sub edit_done {
-	my ($self, $lei) = @_;
-	my $cfg = PublicInbox::Config->git_config_dump($self->{'-f'});
-	my $new_out = $cfg->{'lei.q.output'} // '';
-	return $lei->fail(<<EOM) if ref $new_out;
-$self->{-f} has multiple values of lei.q.output
-please edit again
-EOM
-	return $lei->fail(<<EOM) if $new_out eq '';
-$self->{-f} needs lei.q.output
-please edit again
-EOM
-	my $old_out = $self->{-cfg}->{'lei.q.output'} // '';
-	return if $old_out eq $new_out;
-	my $old_path = $old_out;
-	my $new_path = $new_out;
-	s!$LOCAL_PFX!! for ($old_path, $new_path);
-	my $dir_old = lss_dir_for($lei, \$old_path, 1);
-	my $dir_new = lss_dir_for($lei, \$new_path);
-	return if $dir_new eq $dir_old; # no change, likely
-
-	($old_out =~ m!\Av2:!i || $new_out =~ m!\Av2:!) and
-		return $lei->fail(<<EOM);
-conversions from/to v2 inboxes not supported at this time
-EOM
-
-	return $lei->fail(<<EOM) if -e $dir_new;
-lei.q.output changed from `$old_out' to `$new_out'
-However, $dir_new exists
-EOM
-	# start the conversion asynchronously
-	my $old_sq = PublicInbox::Config::squote_maybe($old_out);
-	my $new_sq = PublicInbox::Config::squote_maybe($new_out);
-	$lei->puts("lei.q.output changed from $old_sq to $new_sq");
-	$lei->qerr("# lei convert $old_sq -o $new_sq");
-	my $v = !$lei->{opt}->{quiet};
-	$lei->{opt} = { output => $new_out, verbose => $v };
-	require PublicInbox::LeiConvert;
-	PublicInbox::LeiConvert::lei_convert($lei, $old_out);
-
-	$lei->fail(<<EOM) if -e $dir_old && !rename($dir_old, $dir_new);
-E: rename($dir_old, $dir_new) error: $!
-EOM
-}
-
 # cf. LeiDedupe->has_entries
 sub has_entries {
 	my $oidx = $_[0]->{oidx} // die 'BUG: no {oidx}';
diff --git a/script/lei b/script/lei
index 99d94b4e..2d84487a 100755
--- a/script/lei
+++ b/script/lei
@@ -127,6 +127,8 @@ while (1) {
 		last;
 	} elsif ($buf =~ /\Achild_error ([0-9]+)\z/) {
 		$x_it_code ||= $1 + 0;
+	} elsif ($buf eq 'wait') {
+		$sigchld->();
 	} else {
 		$sigchld->();
 		die $buf;
diff --git a/t/lei-q-save.t b/t/lei-q-save.t
index 743a7b70..9c17a011 100644
--- a/t/lei-q-save.t
+++ b/t/lei-q-save.t
@@ -215,5 +215,22 @@ test_lei(sub {
 		'absolute path appears in ls-search';
 	lei_ok qw(up ../s -C), "$home/v2s", \'relative lei up';
 	lei_ok qw(up), "$home/s", \'absolute lei up';
+
+	# mess up a config file
+	my @lss = glob("$home/" .
+		'.local/share/lei/saved-searches/*/lei.saved-search');
+	my $out = xqx([qw(git config -f), $lss[0], 'lei.q.output']);
+	xsys($^X, qw(-i -p -e), "s/\\[/\\0/", $lss[0])
+		and xbail "-ipe $lss[0]: $?";
+	lei_ok qw(ls-search);
+	like($lei_err, qr/bad config line.*?\Q$lss[0]\E/,
+		'git config parse error shown w/ lei ls-search');
+	lei_ok qw(up --all), \'up works with bad config';
+	like($lei_err, qr/bad config line.*?\Q$lss[0]\E/,
+		'git config parse error shown w/ lei up');
+	xsys($^X, qw(-i -p -e), "s/\\0/\\[/", $lss[0])
+		and xbail "-ipe $lss[0]: $?";
+	lei_ok qw(ls-search);
+	is($lei_err, '', 'no errors w/ fixed config');
 });
 done_testing;