solver: operate directly on git index

No need to incur extra I/O traffic with a working-tree and
uncompressed files on the filesystem.  git can handle patch
application in memory and we rely on exact blob matching
anyways, so no need for 3way patch application.

1 files changed, 9 insertions, 14 deletions

diff --git a/lib/PublicInbox/SolverGit.pm b/lib/PublicInbox/SolverGit.pm
index d7209e65..8dfc52e1 100644
--- a/lib/PublicInbox/SolverGit.pm
+++ b/lib/PublicInbox/SolverGit.pm
@@ -215,7 +215,7 @@ sub reap ($$) {
         $? == 0 or die "$msg failed: $?";
 }
 
-sub prepare_wt ($$$$) {
+sub prepare_index ($$$$) {
         my ($out, $wt_dir, $existing, $di) = @_;
         my $oid_full = $existing->[1];
         my ($r, $w);
@@ -232,10 +232,7 @@ sub prepare_wt ($$$$) {
         close $w or die "close update-index: $!";
         reap($pid, 'update-index -z --index-info');
 
-        $pid = spawn([@git, qw(checkout-index -a -f -u)]);
-        reap($pid, 'checkout-index -a -f -u');
-
-        print $out "Working tree prepared:\n",
+        print $out "index prepared:\n",
                 "$mode_a $oid_full\t", git_quote($path_a), "\n";
 }
 
@@ -250,7 +247,7 @@ sub do_apply ($$$$) {
         defined(my $err_fd = fileno($out)) or die "fileno(out): $!";
         my $rdr = { 0 => fileno($tmp), 1 => $err_fd, 2 => $err_fd };
         my $cmd = [ qw(git -C), $wt_dir,
-                    qw(apply --whitespace=warn -3 --verbose) ];
+                    qw(apply --cached --whitespace=warn --verbose) ];
         reap(spawn($cmd, undef, $rdr), 'apply');
 
         local $/ = "\0";
@@ -267,11 +264,12 @@ sub do_apply ($$$$) {
 
         $file eq $di->{path_b} or
                 die "index mismatch: file=$file != path_b=$di->{path_b}";
-        my $abs_path = "$wt_dir/$file";
-        -r $abs_path or die "WT_DIR/$file not readable";
-        my $size = -s _;
 
-        print $out "OK $mode_b $oid_b_full $stage\t$file\n";
+        my (undef, undef, $size) = $wt_git->check($oid_b_full);
+
+        defined($size) or die "failed to read_size from $oid_b_full";
+
+        print $out "$mode_b $oid_b_full\t$file\n";
         [ $wt_git, $oid_b_full, 'blob', $size, $di ];
 }
 
@@ -308,10 +306,7 @@ sub apply_patches ($$$$$) {
 
                 # prepare the worktree for patch application:
                 if ($i == 1 && $existing) {
-                        prepare_wt($out, $wt_dir, $existing, $di);
-                }
-                if (!$empty_oid && ! -f "$wt_dir/$di->{path_a}") {
-                        die "missing $di->{path_a} at [$i/$tot] ", di_url($di);
+                        prepare_index($out, $wt_dir, $existing, $di);
                 }
 
                 print $out "\napplying [$i/$tot] ", di_url($di), "\n",