add_commit_links.pl: error out if missing major version number

Reported-by: Tom Lane

Author: Tom Lane

Discussion: https://postgr.es/m/53125.1756591456@sss.pgh.pa.us

src/tools/add_commit_links.pl

@@ -50,6 +50,8 @@ sub process_file
 	# Get major version number from the file name.
 	$file =~ m/-(\d+)\./;
 	my $major_version = $1;
+	die "file name $file is not in the expected format\n"
+		unless defined $major_version;
 
 	open(my $fh, '<', $file) || die "could not open file $file: $!\n";
 	open(my $tfh, '>', $tmpfile) || die "could not open file $tmpfile: $!\n";