lei: fix handling of broken lei.saved-search config files

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/

1 files changed, 18 insertions, 3 deletions

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;