options: Always reset OPTIND in getoptsreset

Commit Message

Herbert Xu May 19, 2024, 11:19 a.m. UTC

On Wed, Jan 04, 2023 at 04:50:34PM +0000, Harald van Dijk wrote:
>
> Personally, I do think it is better if shells allow assigning arbitrary
> values to OPTIND, including unsetting it, and only have the getopts command
> raise an error if the value is non-numeric, but that is my personal opinion
> and I don't see much of a problem if dash decides to go the other way,
> unless POSIX makes it explicit that it is not permitted for shells to do
> this. FWIW, I did make that change for my version, <https://github.com/hvdijk/gwsh/commit/0df0ba33748eb3881b07cb724fd4fa54422ef2bc>,
> if that change is desired for dash it is easy to apply.

I've decided to make getoptsreset always do the reset, regardless
of the value of OPTIND.  Why else would you assign it anyway?

---8<---
Always reset OPTIND if it is modified by the user, regardless of
its value.

Reported-by: наб <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

Comments

Harald van Dijk May 19, 2024, 1:23 p.m. UTC | #1

On 19/05/2024 12:19, Herbert Xu wrote:
> On Wed, Jan 04, 2023 at 04:50:34PM +0000, Harald van Dijk wrote:
>>
>> Personally, I do think it is better if shells allow assigning arbitrary
>> values to OPTIND, including unsetting it, and only have the getopts command
>> raise an error if the value is non-numeric, but that is my personal opinion
>> and I don't see much of a problem if dash decides to go the other way,
>> unless POSIX makes it explicit that it is not permitted for shells to do
>> this. FWIW, I did make that change for my version, <https://github.com/hvdijk/gwsh/commit/0df0ba33748eb3881b07cb724fd4fa54422ef2bc>,
>> if that change is desired for dash it is easy to apply.
> 
> I've decided to make getoptsreset always do the reset, regardless
> of the value of OPTIND.  Why else would you assign it anyway?

This interacts terribly with the not fully reliable but nevertheless 
fairly commonly used "local OPTIND". When the local OPTIND goes out of 
scope and the prior value of OPTIND is restored, the expectation is not 
that option processing restarts from the beginning.

Cheers,
Harald van Dijk

Patch

diff --git a/src/options.c b/src/options.c
index 4d0a53a..c74e4fe 100644
--- a/src/options.c
+++ b/src/options.c
@@ -393,7 +393,7 @@  setcmd(int argc, char **argv)
 
 void getoptsreset(const char *value)
 {
-	shellparam.optind = number(value) ?: 1;
+	shellparam.optind = 1;
 	shellparam.optoff = -1;
 }