[PATCH v2] tests: avoid syntax triggering old dash bug
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Junio C Hamano
Eric Sunshine
hsed@unimetic.com
Ævar Arnfjörð Bjarmason
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Ævar Arnfjörð Bjarmason
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Date
2019-02-13 11:59:51 UTC
Avoid a bug in dash that's been fixed ever since its
ec2c84d ("[PARSER] Fix clobbering of checkkwd", 2011-03-15)[1] first
released with dash v0.5.7 in July 2011. This failing test was
introduced in 5f9674243d ("config: add --expiry-date", 2017-11-18).

This fixes 1/2 tests failing on Debian Lenny & Squeeze. The other
failure is due to 1b42f45255 ("git-svn: apply "svn.pathnameencoding"
before URL encoding", 2016-02-09).

The dash bug is triggered by this test because the heredoc contains a
command embedded in "$()" with a "{}" block coming right after
it. Refactoring the "$()" to e.g. be a variable that was set earlier
will also work around it, but let's instead break up the "EOF" and the
"{}".

An earlier version of this patch[2] mitigated the issue by breaking
the "$()" out of the "{}" block, that worked, but just because it
broke up the "EOF" and "{}" block. Putting e.g. "echo &&" between the
two would also work.

1. https://git.kernel.org/pub/scm/utils/dash/dash.git/
2. https://public-inbox.org/git/20181127164253.9832-1-avarab@gmail.com/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---

On Wed, Nov 28 2018, Junio C Hamano wrote:

> Eric Sunshine <sunshine@sunshineco.com> writes:
>
>> On Tue, Nov 27, 2018 at 11:43 AM Ævar Arnfjörð Bjarmason
>> <avarab@gmail.com> wrote:
>>> Avoid a bug in dash that's been fixed ever since its
>>> ec2c84d ("[PARSER] Fix clobbering of checkkwd", 2011-03-15)[1] first
>>> released with dash v0.5.7 in July 2011.
>>
>> Perhaps enhance the commit message to explain the nature of the bug
>> itself. It is not at all obvious from reading the above or from
>> looking at the diff itself what the actual problem is that the patch
>> is fixing. (And it wasn't even immediately obvious by looking at the
>> commit message of ec2c84d in the dash repository.) To help readers of
>> this patch avoid re-introducing this problem or diagnose such a
>> failure, it might be a good idea to give an example of the syntax
>> which trips up old dash (i.e. a here-doc followed immediately by a
>> {...} expression) and the actual error message 'Syntax error: "}"
>> unexpected'.
>
> Indeed.  From the patch text, I would not have even guessed.  I was
> wondering if there were interactions with "" and $() inside it.
>
> If having {...} immediately after a here-doc is a problem, then the
> patch should not touch existing code at all, but instead insert a
> new line, perhaps like
>
> 	: avoid open brace immediately after here-doc for old dash

Late re-roll. Now using a variant of that suggestion, and with an
updated commit message explaining what the issue in dash is exactly
and why it was triggered.

This isn't a 2.21 regression, but sending it in the rc window anyway
in case you'd like to queue an obviously working minor portability
fix.

 t/t1300-config.sh | 1 +
 1 file changed, 1 insertion(+)

diff --git a/t/t1300-config.sh b/t/t1300-config.sh
index 9652b241c7..428177c390 100755
--- a/t/t1300-config.sh
+++ b/t/t1300-config.sh
@@ -892,6 +892,7 @@ test_expect_success 'get --expiry-date' '
 	1510348087
 	0
 	EOF
+	: "work around heredoc parsing bug fixed in dash 0.5.7 (in ec2c84d)" &&
 	{
 		echo "$rel_out $(git config --expiry-date date.valid1)"
 		git config --expiry-date date.valid2 &&
-- 
2.20.1.611.gfbb209baf1