Re: [RFC/PATCH 0/2] here-doc test bodies

From: Jeff King <peff@peff.net>
To: Derrick Stolee <stolee@gmail.com>
Cc: git@vger.kernel.org
Subject: Re: [RFC/PATCH 0/2] here-doc test bodies
Date: Fri, 9 Apr 2021 21:34:23 -0400	[thread overview]
Message-ID: <YHEAn7u4SXlmZsfZ@coredump.intra.peff.net> (raw)
In-Reply-To: <42b187cb-6417-0353-cf63-c6379be53208@gmail.com>

On Fri, Apr 09, 2021 at 09:03:24PM -0400, Derrick Stolee wrote:

> On 4/9/2021 6:26 PM, Jeff King wrote:
> > I've been wanting to do this for years, but after getting bitten by a
> > misplaced quote the other day, I finally did. This series allows you to
> > do:
> > 
> >   test_expect_success <<\EOT
> >           something 'with single quotes'
> >   EOT
> > 
> > Thoughts?
> 
> Odd. I _just_ hit this for the first time today. I didn't know
> about the $SQ trick, so I just modified my 'sed' call to drop
> the single quotes from the string I was trying to match [1].
> 
> [1] https://lore.kernel.org/git/36aa6837-722c-9ef0-84cc-77e982db9f6e@gmail.com/

Yep, that case would definitely benefit. We have a variety of little
workarounds now, but it would be nice to not even need them.

> I think this is a good pattern for this kind of thing. I
> imagine that if the test itself needed heredocs, then they
> would be interpreted correctly when evaluating stdin (as
> long as a different identifier is used).

Yeah, some of the tests I converted in t1404 have their own here-docs.
It works for the same reason that the single-quoted snippets work: the
outer doc slurps the whole thing to the "EOT" marker. So we do not even
consider the inner here-docs until we are eval-ing the snippet.

> I also like the "EOT" pattern as an example.

I think it would make sense to have a convention here for readability.
Also, I added this to the sharness vim highlighter from [1]:

diff --git a/sharness.vim b/sharness.vim
index 6ffc64f..7dbcd18 100644
--- a/sharness.vim
+++ b/sharness.vim
@@ -21,6 +21,9 @@ syn region shsTestBody contained transparent excludenl matchgroup=shQuote start=
 syn region shsTestBody contained oneline transparent excludenl keepend matchgroup=shQuote start=+ '+hs=s+1 end=+'$+ contains=@shSubShList
 syn region shsTestBody contained oneline transparent excludenl keepend matchgroup=shQuote start=+ "+hs=s+1 end=+"$+ contains=@shSubShList
 
+" here-doc body
+syn region shsTestBody contained transparent excludenl matchgroup=shQuote start=+ <<\\EOT+ end=+EOT$+ contains=@shSubShList
+
 syn match shsPrereq contained "\<[A-Z_,]\+\>" nextgroup=shsTestTitle
 syn match shsPrereqLazy contained "\<[A-Z_,]\+\>" nextgroup=shsTestBody
 

which makes the innards look nice. :) I think it could be written to
allow any marker, but there would probably need to be some magic with
matching the opening and closing markers.

-Peff

[1] https://lore.kernel.org/git/CAMP44s1D-Zp3KDS+Hi74a=Lkc7Nc_0qiEzQEF0Pmj=bD8i+=JQ@mail.gmail.com/
