Re: [PATCH 3/4] tests: drop here-doc check from internal chain-linter

[Jeff King <peff@peff.net>]

On Tue, Mar 28, 2023 at 10:37:02PM -0400, Jeff King wrote:

> I just think chainlint.pl is doing a good enough job of catching it that
> we can rely on it. I'll be curious if Eric has input there on whether it
> can do even better, which would remove all of the caveats from the
> commit message.

So I _think_ it's something like this:

diff --git a/t/chainlint.pl b/t/chainlint.pl
index e966412999a..6b8c1de5208 100755
--- a/t/chainlint.pl
+++ b/t/chainlint.pl
@@ -171,6 +171,9 @@ sub swallow_heredocs {
 		my $start = pos($$b);
 		my $indent = $tag =~ s/^\t// ? '\\s*' : '';
 		$$b =~ /(?:\G|\n)$indent\Q$tag\E(?:\n|\z)/gc;
+		if (pos($$b) == $start) {
+			die "oops, we did not find the end of the heredoc";
+		}
 		my $body = substr($$b, $start, pos($$b) - $start);
 		$self->{lineno} += () = $body =~ /\n/sg;
 	}

But I wasn't sure how to surface a clean error from here, since we're in
the Lexer. Maybe we just accumulate a "problems" array here, and then
roll those up via the TestParser? I'm not very familiar with the
arrangement of that part of the script.

And I say "think" because the thing I was worried about is that we'd do
this lexing at too high a level, and accidentally walk past the end of
the test. Which would mean getting fooled by;

  test_expect_success 'this one is broken' '
	cat >foo <<\EOF
	oops, we are missing our here-doc end
  '

  test_expect_success 'this one is ok' '
	cat >foo <<\EOF
	this one is OK, but we would not want to confuse
	its closing tag for the missing one
	EOF
  '

But it looks like Lexer::swallow_heredocs gets to see the individual
test snippets.

-Peff