midam - "Message-Id git am"

.midam.pl

#!/usr/bin/perl

# midam: Message-Id git am
# Author: Emily Shaffer (@nasamuffin)
#
# Applies patches based on a Message-Id.
# If the Message-Id provided is a cover letter ([PATCH 0/]), apply all
# messages with In-Reply-To: <ID> instead.

use autodie;

# Only take one argument.
$#ARGV+1==1 or die "Usage: midam \"<message-id>\"";
my $mid = $ARGV[0];

# The mailing list name.
my $maildir = '/usr/local/google/home/emilyshaffer/git-maillist';

# Fetch the latest mail.
my $fetcher = join('', 'git -C ', $maildir, ' pull');
(system $fetcher == 0) or warn "Couldn't fetch mail; using stale repo";

# git-grep the message with provided ID from the archive
my @patches = find_messages("Message-Id:");

# We should only have one message match, using the Message-Id prefix.
$#patches+1==1 or die "More than one message with ID $mid!";

# Check whether it's a cover letter
my $topPatch = join('/', $maildir, $patches[0]);
open(my $fh, "<", $topPatch);
my @lines = <$fh>;
my $series = 0;
foreach (@lines) {
	# Cover letters contain "[PATCH 0/n]"
	if (m|Subject: \[(PATCH \|RFC )+0+/\d\]|) {
		print "Cover letter supplied, applying all replies.\n";
		@patches = find_messages("In-Reply-To:");
		last;
	}
}

# apply the patch(es) with --interactive so user has a last chance to stop it
foreach $patch (@patches) {
	my $patcher = join('', 'git am --interactive ', $maildir, '/', $patch);
	system $patcher
}

#### Subroutines ####

# git-grep messages from the archive matching a header and message-id
sub find_messages {
	my $header_pfx = shift;
	my $grepper = join('', 'git -C ', $maildir,
		' --no-pager grep -Fl --full-name "', $header_pfx, ' ', $mid,
		'" |');
	open(PATCHES, $grepper);
	chomp(my @patches =  <PATCHES>);
	close(PATCHES);
	
	return @patches;
}