parser: Only accept single-digit parameter expansion outside of braces

[Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>]

On Thu, Apr 25, 2019 at 01:39:52AM +0000, Michael Orlitzky wrote:
> The POSIX spec says,
> 
>   The parameter name or symbol can be enclosed in braces, which are
>   optional except for positional parameters with more than one digit or
>   when parameter is a name and is followed by a character that could be
>   interpreted as part of the name.
> 
> However, dash seems to diverge from that behavior when we get to $10:
> 
>   $ cat test.sh
>   echo $10
> 
>   $ dash ./test.sh one two three four five six seven eight nine ten
>   ten
> 
>   $ bash ./test.sh one two three four five six seven eight nine ten
>   one0

This patch should fix the problem.

Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

diff --git a/src/parser.c b/src/parser.c
index 1f9e8ec..2f14bf3 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -1268,7 +1268,7 @@ varname:
 			do {
 				STPUTC(c, out);
 				c = pgetc_eatbnl();
-			} while (is_digit(c));
+			} while (!subtype && is_digit(c));
 		} else if (c != '}') {
 			int cc = c;
 
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
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