Add Porting/bisect.pl, to automate bisecting a perl code test case.

1 files changed, 70 insertions, 0 deletions

diff --git a/Porting/bisect.pl b/Porting/bisect.pl
new file mode 100755
index 0000000000..bc462aa04c
--- /dev/null
+++ b/Porting/bisect.pl
@@ -0,0 +1,70 @@
+#!/usr/bin/perl -w
+use strict;
+
+my $start_time = time;
+
+use Getopt::Long;
+
+sub usage {
+    die "$0: [--start revlike] [--end revlike] [--target=...] [-j=4] [--expect-pass=0|1] thing to test";
+}
+
+my %options;
+unless(GetOptions(\%options,
+		  'start=s',
+		  'end=s',
+		  'target=s',
+		  'jobs|j=i',
+		  'expect-pass=i',
+		  'expect-fail',
+		  'one-liner|e=s',
+		 )) {
+    usage();
+}
+
+my $start = delete $options{start};
+# Currently the earliest version that the runner can build
+$start = 'perl-5.005' unless defined $start;
+my $end = delete $options{end};
+$end = 'blead' unless defined $end;
+
+system "git rev-parse $start >/dev/null" and die;
+system "git rev-parse $end >/dev/null" and die;
+
+my $modified = () = `git ls-files --modified --deleted --others`;
+
+die "This checkout is not clean - $modified modified or untracked file(s)"
+    if $modified;
+
+system "git bisect reset" and die;
+
+my @ARGS;
+foreach (sort keys %options) {
+    push @ARGS, defined $options{$_} ? "--$_=$options{$_}" : "--$_";
+}
+push @ARGS, @ARGV;
+
+my $runner = $0;
+$runner =~ s/bisect\.pl/bisect-runner.pl/;
+
+die "Can't find bisect runner $runner" unless -f $runner;
+
+# Sanity check the first and last revisions:
+system "git checkout $start" and die;
+my $ret = system $^X, $runner, @ARGS;
+die "Runner returned $ret, not 0 for start revision" if $ret;
+
+system "git checkout $end" and die;
+$ret = system $^X, $runner, @ARGS;
+die "Runner returned $ret for end revision" unless $ret;
+
+system "git bisect start" and die;
+system "git bisect good $start" and die;
+system "git bisect bad $end" and die;
+
+# And now get git bisect to do the hard work:
+system 'git', 'bisect', 'run', $^X, $runner, @ARGS and die;
+
+my $end_time = time;
+
+printf "That took %d seconds\n", $end_time - $start_time;