fix -j mode to preserve stderr distinct from stdout,

while still buffering them together

diff --git a/mr b/mr
index 68772a0177369297a3a768672a474645592f5df5..1aee75afa54ed0c40eb5811b034774af234917f5 100755 (executable)
--- a/mr
+++ b/mr
@@ -160,10 +160,8 @@ recurse into deeper repositories.
 =item -j number
 
 Run the specified number of jobs in parallel. This can greatly speed up
-operations such as updates.
-
-Note that in -j mode, all output of the jobs goes to standard output, even
-output that would normally go to standard error.
+operations such as updates. It is not recommended for interactive
+operations.
 
 =back
 
@@ -443,6 +441,7 @@ if ($jobs > 1) {
 else {
        foreach my $repo (@repos) {
                record($repo, action($action, @$repo));
+               print "\n";
        }
 }
 if (! @ok && ! @failed && ! @skipped) {
@@ -538,7 +537,6 @@ sub action { #{{{
                        join(" ", map { s/\//\/\//g; s/"/\"/g; '"'.$_.'"' } @ARGV);
                print STDERR "mr $action: running >>$command<<\n" if $verbose;
                my $ret=system($command);
-               print "\n";
                if ($ret != 0) {
                        if (($? & 127) == 2) {
                                print STDERR "mr $action: interrupted\n";
@@ -579,43 +577,58 @@ sub mrs { #{{{
                while ($running < $jobs && @repos) {
                        $running++;
                        my $repo = shift @repos;
-                       my $pid = open(my $fh, "-|");
-                       if (! $pid) {
-                               open(STDERR, ">&STDOUT");
+                       pipe(my $outfh, CHILD_STDOUT);
+                       pipe(my $errfh, CHILD_STDERR);
+                       unless (my $pid = fork) {
+                               die "cannot fork: $!" unless defined $pid;
+                               open(STDOUT, ">&CHILD_STDOUT") || die "reopen stdout: $!";
+                               open(STDERR, ">&CHILD_STDERR") || die "reopen stderr: $!";
+                               close CHILD_STDOUT;
+                               close CHILD_STDERR;
+                               close $outfh;
+                               close $errfh;
                                exit action($action, @$repo);
                        }
+                       close CHILD_STDOUT;
+                       close CHILD_STDERR;
                        push @active, $repo;
-                       push @fhs, $fh;
-                       push @out, "";
+                       push @fhs, [$outfh, $errfh];
+                       push @out, ['',     ''];
                }
                my ($rin, $rout) = ('','');
                my $nfound;
-               foreach my $x (@fhs) {
-                       next unless defined $x;
-                       vec($rin, fileno($x), 1) = 1;
+               foreach my $fh (@fhs) {
+                       next unless defined $fh;
+                       vec($rin, fileno($fh->[0]), 1) = 1 if defined $fh->[0];
+                       vec($rin, fileno($fh->[1]), 1) = 1 if defined $fh->[1];
                }
                $nfound = select($rout=$rin, undef, undef, 1);
-               foreach my $i (0..$#fhs) {
-                       my $fh = $fhs[$i];
-                       next unless defined $fh;
-                       if (vec($rout, fileno($fh), 1) == 1) {
-                               my $r = '';
-                               if (sysread($fh, $r, 1024) == 0) {
-                                       close($fh);
-                                       record($active[$i], $? >> 8);
-                                       $fhs[$i] = undef;
-                                       $running--;
-                                       print $out[$i];
-                                       $out[$i]='';
+               foreach my $channel (0, 1) {
+                       foreach my $i (0..$#fhs) {
+                               next unless defined $fhs[$i];
+                               my $fh = $fhs[$i][$channel];
+                               next unless defined $fh;
+                               if (vec($rout, fileno($fh), 1) == 1) {
+                                       my $r = '';
+                                       if (sysread($fh, $r, 1024) == 0) {
+                                               close($fh);
+                                               $fhs[$i][$channel] = undef;
+                                               if (! defined $fhs[$i][0] &&
+                                                   ! defined $fhs[$i][1]) {
+                                                       print STDOUT $out[$i][0];
+                                                       print STDERR $out[$i][1];
+                                                       print "\n";
+                                                       record($active[$i], $? >> 8);
+                                                       splice(@fhs, $i, 1);
+                                                       splice(@active, $i, 1);
+                                                       splice(@out, $i, 1);
+                                                       $running--;
+                                               }
+                                       }
+                                       $out[$i][$channel] .= $r;
                                }
-                               $out[$i] .= $r;
                        }
                }
-               while (@fhs and !defined $fhs[0]) {
-                       shift @active;
-                       shift @fhs;
-                       shift @out;
-               }
        }
 } #}}}