[v2 PATCH] expand: Escape minus sign in arithmetic expansion

[Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>]

On Mon, May 28, 2018 at 12:22:00AM +0800, Herbert Xu wrote:
> The minus sign generated from arithmetic expansion is currently
> unquoted which causes anomalies when the result is used in where
> the quoting matters.
> 
> This patch fixes it by explicitly calling memtodest for the minus
> sign.
> 
> Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

This was buggy.  Here is an update.

---8<---
The minus sign generated from arithmetic expansion is currently
unquoted which causes anomalies when the result is used in where
the quoting matters.

This patch fixes it by explicitly calling memtodest for the minus
sign.

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

diff --git a/src/expand.c b/src/expand.c
index 7a51766..7ed1bc0 100644
--- a/src/expand.c
+++ b/src/expand.c
@@ -490,7 +490,14 @@ expari(int flag)
 	result = arith(p + 1);
 	popstackmark(&sm);
 
-	len = cvtnum(result);
+	len = 0;
+	if (result < 0) {
+		memtodest("-", 1, flag);
+		result = -result;
+		len++;
+	}
+
+	len += cvtnum(result);
 
 	if (likely(!(flag & EXP_QUOTED)))
 		recordregion(begoff, begoff + len, 0);
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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