From: Martijn Dekker <martijn@inlv.org>
To: Harald van Dijk <harald@gigawatt.nl>,
DASH shell mailing list <dash@vger.kernel.org>
Subject: [PATCH] parseheredoc: fix alias expansion: save and restore checkkwd
Date: Sat, 25 Jan 2020 13:19:56 +0100 [thread overview]
Message-ID: <0c506ff6-6da5-f117-b0b3-d3cf7cc008ed@inlv.org> (raw)
In-Reply-To: <f40ce455-afd8-05f4-e594-4395bb2a8ed0@gigawatt.nl>
[-- Attachment #1: Type: text/plain, Size: 1677 bytes --]
Op 25-01-20 om 02:38 schreef Harald van Dijk:
> On 25/01/2020 01:13, Harald van Dijk wrote:
>> On 24/01/2020 23:48, Martijn Dekker wrote:
>>> There is a regression involving alias expansion, a here-document, and
>>> a command substitution. The following worked fine until dash 0.5.8;
>>> it throws a syntax error as of dash 0.5.9.
>>>
>>> alias BEGIN='{' END='}'
>>> BEGIN
>>> cat <<eof
>>> $(echo hi)
>>> eof
>>> END
>>
>> Nice find.
>>
>> When the newline after cat <<eof is seen, checkkwd is changed to
>> indicate that the shell is in a state where aliases can be expanded.
>> Then, parseheredoc() is called, which in turn calls readtoken1() to
>> parse the here-document. readtoken() re-sets checkkwd once it is done,
>> but readtoken1() does not, so normally this preserves the "can expand
>> aliases" state. However, nested command substitutions do reset
>> checkkwd, so things break.
>>
>> Until 0.5.8, parseheredoc() was called first, and only after that did
>> checkkwd get changed.
>>
>> Either parseheredoc() needs to save and restore checkkwd, or the code
>> calling parseheredoc() needs to ensure that it sets checkkwd as
>> appropriate afterwards.
Saving and restoring checkkwd in parseheredoc() seems the simplest and
the most future-proof, so here's a patch to do that.
> There is another place that parseheredoc() can be called from where
> checkkwd was not being corrected afterwards:
>
> alias BEGIN='{' END='}'
> : <<EOF &&
> $(echo hi)
> EOF
> BEGIN
> echo ok
> END
>
> This has been failing for longer.
The patch fixes this as well.
--
modernish -- harness the shell
https://github.com/modernish/modernish
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diff --git a/src/parser.c b/src/parser.c
index b318b08..8840262 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -661,6 +661,7 @@ parsefname(void)
STATIC void
parseheredoc(void)
{
+ int savecheckkwd = checkkwd;
struct heredoc *here;
union node *n;
@@ -683,6 +684,8 @@ parseheredoc(void)
here->here->nhere.doc = n;
here = here->next;
}
+
+ checkkwd = savecheckkwd;
}
STATIC int
next prev parent reply other threads:[~2020-01-25 12:20 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-24 23:48 Alias/heredoc/cmdsubst regression Martijn Dekker
2020-01-25 1:13 ` Harald van Dijk
2020-01-25 1:38 ` Harald van Dijk
2020-01-25 12:19 ` Martijn Dekker [this message]
2020-01-25 16:17 ` [PATCH] parseheredoc: fix alias expansion: save and restore checkkwd Harald van Dijk
2020-01-25 16:26 ` Alias/heredoc/cmdsubst regression Martijn Dekker
2020-01-25 16:33 ` Harald van Dijk
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