implement public-inbox-purge tool

Expose the ->purge functionality of V2Writable for rewriting
git history to permanently purge messages from history.  This
may be necessary for legal reasons.

Usage:

	# requires ~/.public-inbox/config
	public-inbox-purge --all </path/to/message-to-purge

	# good for testing with unconfigured inboxes:
	public-inbox-purge $INBOX_DIR </path/to/message-to-purge

1 files changed, 97 insertions, 0 deletions

diff --git a/t/purge.t b/t/purge.t
new file mode 100644
index 00000000..94060055
--- /dev/null
+++ b/t/purge.t
@@ -0,0 +1,97 @@
+# Copyright (C) 2019 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+use strict;
+use warnings;
+use Test::More;
+use File::Temp qw/tempdir/;
+require './t/common.perl';
+require_git(2.6);
+my @mods = qw(IPC::Run DBI DBD::SQLite Search::Xapian);
+foreach my $mod (@mods) {
+        eval "require $mod";
+        plan skip_all => "missing $_ for t/purge.t" if $@;
+};
+use Cwd qw(abs_path);
+my $purge = abs_path('blib/script/public-inbox-purge');
+my $tmpdir = tempdir('pi-purge-XXXXXX', TMPDIR => 1, CLEANUP => 1);
+use_ok 'PublicInbox::V2Writable';
+my $mainrepo = "$tmpdir/v2";
+my $ibx = PublicInbox::Inbox->new({
+        mainrepo => $mainrepo,
+        name => 'test-v2purge',
+        version => 2,
+        -primary_address => 'test@example.com',
+        indexlevel => 'basic',
+});
+
+my $raw = <<'EOF';
+From: a@example.com
+To: test@example.com
+Subject: this is a subject
+Message-ID: <a-mid@b>
+Date: Fri, 02 Oct 1993 00:00:00 +0000
+
+Hello World
+
+EOF
+
+local $ENV{NPROC} = '1';
+my $cfgfile = "$tmpdir/config";
+local $ENV{PI_CONFIG} = $cfgfile;
+open my $cfg_fh, '>', $cfgfile or die "open: $!";
+
+my $v2w = PublicInbox::V2Writable->new($ibx, 1);
+my $mime = PublicInbox::MIME->new($raw);
+ok($v2w->add($mime), 'add message to be purged');
+$v2w->done;
+
+# failing cases, first:
+my $in = "$raw\nMOAR\n";
+my ($out, $err) = ('', '');
+ok(IPC::Run::run([$purge, '-f', $mainrepo], \$in, \$out, \$err),
+        'purge -f OK');
+
+$out = $err = '';
+ok(!IPC::Run::run([$purge, $mainrepo], \$in, \$out, \$err),
+        'mismatch fails without -f');
+is($? >> 8, 1, 'missed purge exits with 1');
+
+# a successful case:
+ok(IPC::Run::run([$purge, $mainrepo], \$raw, \$out, \$err), 'match OK');
+like($out, qr/^\t[a-f0-9]{40,}/m, 'removed commit noted');
+
+# add (old) vger filter to config file
+print $cfg_fh <<EOF or die "print $!";
+[publicinbox "test-v2purge"]
+        mainrepo = $mainrepo
+        address = test\@example.com
+        indexlevel = basic
+        filter = PublicInbox::Filter::Vger
+EOF
+close $cfg_fh or die "close: $!";
+
+ok($v2w->add($mime), 'add vger-signatured message to be purged');
+$v2w->done;
+
+my $pre_scrub = $raw . <<'EOF';
+
+--
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+EOF
+
+$out = $err = '';
+ok(chdir('/'), "chdir / OK for --all test");
+ok(IPC::Run::run([$purge, '--all'], \$pre_scrub, \$out, \$err),
+        'scrub purge OK');
+like($out, qr/^\t[a-f0-9]{40,}/m, 'removed commit noted');
+# diag "out: $out"; diag "err: $err";
+
+$out = $err = '';
+ok(!IPC::Run::run([$purge, '--all' ], \$pre_scrub, \$out, \$err),
+        'scrub purge not idempotent without -f');
+# diag "out: $out"; diag "err: $err";
+
+done_testing();