[PATCH] cmd: setexpr: fix no matching string in gsub return empty value

[Lukas Funke]

Hi Massimiliano,

On 02.02.2024 15:36, Massimiliano Minella wrote:
> From: Massimiliano Minella <massimiliano.minella at se.com>
> 
> In gsub, when the destination string is empty, the string 't' is
> provided and the regular expression doesn't match, then the final result
> is an empty string.
> 
> Example:
> 
> => echo ${foo}
> 
> => setenv foo
> => setexpr foo gsub e a bar
> => echo ${foo}
> 
> =>
> 
> The variable ${foo} should contain "bar" and the lack of match shouldn't
> be considered an error.
> 
> This patch fixes the erroneous behavior by removing the return
> statement and breaking out of the loop in case of lack of match.
> 
> Also add a test for the no match case.
> 
> Signed-off-by: Massimiliano Minella <massimiliano.minella at se.com>
> ---
>   cmd/setexpr.c      |  6 ++----
>   test/cmd/setexpr.c | 10 ++++++++++
>   2 files changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/cmd/setexpr.c b/cmd/setexpr.c
> index 233471f6cb..6a7c0c914b 100644
> --- a/cmd/setexpr.c
> +++ b/cmd/setexpr.c
> @@ -216,14 +216,12 @@ int setexpr_regex_sub(char *data, uint data_size, char *nbuf, uint nbuf_size,
>   		if (res == 0) {
>   			if (loop == 0) {
>   				debug("%s: No match\n", data);
> -				return 1;
>   			} else {
> -				break;
> +				debug("## MATCH ## %s\n", data);
>   			}
> +			break;
>   		}
>   
> -		debug("## MATCH ## %s\n", data);
> -
>   		if (!s)
>   			return 1;
>   
> diff --git a/test/cmd/setexpr.c b/test/cmd/setexpr.c
> index 312593e1e3..ee329e94b8 100644
> --- a/test/cmd/setexpr.c
> +++ b/test/cmd/setexpr.c
> @@ -179,6 +179,16 @@ static int setexpr_test_regex(struct unit_test_state *uts)
>   	val = env_get("mary");
>   	ut_asserteq_str("this is a test", val);
>   
> +	/* No match */
> +	ut_assertok(run_command("setenv fred 'this is a test'", 0));
> +	ut_assertok(run_command("setenv mary ''", 0));
> +	ut_assertok(run_command("setexpr fred gsub us is \"${fred}\"", 0));
> +	ut_assertok(run_command("setexpr mary gsub us is \"${fred}\"", 0));
> +	val = env_get("fred");
> +	ut_asserteq_str("this is a test", val);
> +	val = env_get("mary");
> +	ut_asserteq_str("this is a test", val);
> +
>   	unmap_sysmem(buf);
>   
>   	return 0;

Tested-by: Lukas Funke <lukas.funke-oss at weidmueller.com>

lgtm.

Could you maybe also update the documentation in 
'doc/usage/cmd/setexpr.rst' in order to document this behaviour?

btw: I removed Roland from the address list, since his mail will bounce.

Best regards,
Lukas