Git.pm: allow pipes to be closed prior to calling command_close_bidi_pipe

diff --git a/perl/Git.pm b/perl/Git.pm
index 931047c51da22cddefe0eab08d0fdaa595daefef..620e0f9e51100d0cba6593fb3c0236d79087f819 100644 (file)
--- a/perl/Git.pm
+++ b/perl/Git.pm
@@ -267,13 +267,13 @@ sub command {
 
        if (not defined wantarray) {
                # Nothing to pepper the possible exception with.
-               _cmd_close($fh, $ctx);
+               _cmd_close($ctx, $fh);
 
        } elsif (not wantarray) {
                local $/;
                my $text = <$fh>;
                try {
-                       _cmd_close($fh, $ctx);
+                       _cmd_close($ctx, $fh);
                } catch Git::Error::Command with {
                        # Pepper with the output:
                        my $E = shift;
@@ -286,7 +286,7 @@ sub command {
                my @lines = <$fh>;
                defined and chomp for @lines;
                try {
-                       _cmd_close($fh, $ctx);
+                       _cmd_close($ctx, $fh);
                } catch Git::Error::Command with {
                        my $E = shift;
                        $E->{'-outputref'} = \@lines;
@@ -313,7 +313,7 @@ sub command_oneline {
        my $line = <$fh>;
        defined $line and chomp $line;
        try {
-               _cmd_close($fh, $ctx);
+               _cmd_close($ctx, $fh);
        } catch Git::Error::Command with {
                # Pepper with the output:
                my $E = shift;
@@ -381,7 +381,7 @@ sub command_input_pipe {
 sub command_close_pipe {
        my ($self, $fh, $ctx) = _maybe_self(@_);
        $ctx ||= '<unknown>';
-       _cmd_close($fh, $ctx);
+       _cmd_close($ctx, $fh);
 }
 
 =item command_bidi_pipe ( COMMAND [, ARGUMENTS... ] )
@@ -418,7 +418,7 @@ sub command_bidi_pipe {
 is:
 
        my ($pid, $in, $out, $ctx) = $r->command_bidi_pipe('cat-file --batch-check');
-       print "000000000\n" $out;
+       print $out "000000000\n";
        while (<$in>) { ... }
        $r->command_close_bidi_pipe($pid, $in, $out, $ctx);
 
@@ -426,23 +426,26 @@ sub command_bidi_pipe {
 currently it is simply the command name but in future the context might
 have more complicated structure.
 
+C<PIPE_IN> and C<PIPE_OUT> may be C<undef> if they have been closed prior to
+calling this function.  This may be useful in a query-response type of
+commands where caller first writes a query and later reads response, eg:
+
+       my ($pid, $in, $out, $ctx) = $r->command_bidi_pipe('cat-file --batch-check');
+       print $out "000000000\n";
+       close $out;
+       while (<$in>) { ... }
+       $r->command_close_bidi_pipe($pid, $in, undef, $ctx);
+
+This idiom may prevent potential dead locks caused by data sent to the output
+pipe not being flushed and thus not reaching the executed command.
+
 =cut
 
 sub command_close_bidi_pipe {
        local $?;
-       my ($pid, $in, $out, $ctx) = @_;
-       foreach my $fh ($in, $out) {
-               unless (close $fh) {
-                       if ($!) {
-                               carp "error closing pipe: $!";
-                       } elsif ($? >> 8) {
-                               throw Git::Error::Command($ctx, $? >>8);
-                       }
-               }
-       }
-
+       my ($self, $pid, $in, $out, $ctx) = _maybe_self(@_);
+       _cmd_close($ctx, (grep { defined } ($in, $out)));
        waitpid $pid, 0;
-
        if ($? >> 8) {
                throw Git::Error::Command($ctx, $? >>8);
        }
@@ -1355,9 +1358,11 @@ sub _setup_git_cmd_env {
 
 # Close pipe to a subprocess.
 sub _cmd_close {
-       my ($fh, $ctx) = @_;
-       if (not close $fh) {
-               if ($!) {
+       my $ctx = shift @_;
+       foreach my $fh (@_) {
+               if (close $fh) {
+                       # nop
+               } elsif ($!) {
                        # It's just close, no point in fatalities
                        carp "error closing pipe: $!";
                } elsif ($? >> 8) {