[PATCH] Drop multi-byte character in argstr when discard is on

On Thu, Apr 23, 2026 at 02:22:15PM +0000, Grégory Pakosz wrote:
> 
> It seems that Dash regressed (but I don't know when).
> 
> $ dash -c 'x=X; printf "before: %s (%d)\n" "$x" "${#x}"; x=${x:-↗};
> printf "after: %s (%d)\n" "$x" "${#x}"'
> before: ↗ (1)
> after: X↗ (2)
> 
> I'm using Dash 0.5.13.2 on macOS, installed via Homebrew.
> The bug seems to be locale irrelevant.

Thank you.  Please try this patch:

---8<---
The multi-byte character should not be copied to the destination
in argstr if the discard flag is enabled.  Fix it.

Reported-by: Grégory Pakosz <[email protected]>
Fixes: 6c44f4ee0c2b ("parser: Add support for multi-byte characters")
Signed-off-by: Herbert Xu <[email protected]>

diff --git a/src/expand.c b/src/expand.c
index bbf8454..76e67ce 100644
--- a/src/expand.c
+++ b/src/expand.c
@@ -379,7 +379,8 @@ addquote:
 			if (c == CTLESC)
 				startloc += ml;
 			p += mb & 0xff;
-			expdest = stnputs(p, ml, expdest);
+			if (!(flag & EXP_DISCARD))
+				expdest = stnputs(p, ml, expdest);
 			p += mb >> 8;
 			break;
 		case CTLESC:
-- 
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt