[PATCH 09/14] git: speed up ->git_path for non-worktrees

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

Only worktrees need to use `git rev-parse --git-path', so avoid
the spawn overhead of a new process.  With the SolverGit.pm
limit on coderepo scans disabled and scanning over 800 git repos
for git@vger matches, this reduces up xt/solver.t times by
roughly 25%.
---
 lib/PublicInbox/Git.pm | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/lib/PublicInbox/Git.pm b/lib/PublicInbox/Git.pm
index 7c6e15b7..a374649f 100644
--- a/lib/PublicInbox/Git.pm
+++ b/lib/PublicInbox/Git.pm
@@ -100,14 +100,17 @@ sub new {
 sub git_path ($$) {
 	my ($self, $path) = @_;
 	$self->{-git_path}->{$path} //= do {
-		local $/ = "\n";
-		chomp(my $str = $self->qx(qw(rev-parse --git-path), $path));
-
-		# git prior to 2.5.0 did not understand --git-path
-		if ($str eq "--git-path\n$path") {
-			$str = "$self->{git_dir}/$path";
+		my $d = "$self->{git_dir}/$path";
+		if (-e $d) {
+			$d;
+		} else {
+			local $/ = "\n";
+			my $s = $self->qx(qw(rev-parse --git-path), $path);
+			chomp $s;
+
+			# git prior to 2.5.0 did not understand --git-path
+			$s eq "--git-path\n$path" ? $d : $s;
 		}
-		$str;
 	};
 }