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Re: [PATCH 2/2] ref-filter: 'contents:trailers' show error if `:` is missing

From
Junio C Hamano <gitster@pobox.com>
Date
Aug 19, 2020, 17:55 UTC
Message-ID
<xmqqv9hettag.fsf@gitster.c.googlers.com>
In-Reply-To
<7daf9335a501b99c29e299f72823fcb7e549e748.1597841551.git.gitgitgadget@gmail.com>
"Hariom Verma via GitGitGadget" <gitgitgadget@gmail.com> writes:
Show 15 quoted lines
> From: Hariom Verma <hariom18599@gmail.com>
>
> The 'contents' atom does not show any error if used with 'trailers'
> atom and semicolon is missing before trailers arguments.
>
> e.g %(contents:trailersonly) works, while it shouldn't.
>
> It is definitely not an expected behavior.
>
> Let's fix this bug.
>
> Mentored-by: Christian Couder <chriscool@tuxfamily.org>
> Mentored-by: Heba Waly <heba.waly@gmail.com>
> Signed-off-by: Hariom Verma <hariom18599@gmail.com>
> ---

Nice spotting. 7a5edbdb (ref-filter.c: parse trailers arguments with %(contents) atom, 2017-10-01) talks about being deliberate about the case where skip_prefix(":") does not find a colon after the "trailers" token, but from the message it is clear that it expected that the case happens only when "trailers" is at the end of the string.

The new helper that is overly verbose and may be overkill.
Shouldn't this be clear enough, equivalent and sufficient?
	else if (skip_prefix(arg, "trailers", &arg) &&
		 (!*arg || *arg == ':'))) {
		if (trailers_atom_parser(...);

That is, we not just make sure the string begins with "trailers", but also make sure it either (1) ends the string (i.e. the token is just "trailers"), or (2) is followed by a colon ':', before entering the block to handle "trailers[:anything]". If we later add a new atom "trailersonly", that will not be handled here, but elsewhere in the "else if" cascade.

Show 43 quoted lines
>  ref-filter.c            | 21 ++++++++++++++++++---
>  t/t6300-for-each-ref.sh |  9 +++++++++
>  2 files changed, 27 insertions(+), 3 deletions(-)
>
> diff --git a/ref-filter.c b/ref-filter.c
> index ba85869755..dc31fbbe51 100644
> --- a/ref-filter.c
> +++ b/ref-filter.c
> @@ -332,6 +332,22 @@ static int trailers_atom_parser(const struct ref_format *format, struct used_ato
>  	return 0;
>  }
>  
> +static int check_format_field(const char *arg, const char *field, const char **option)
> +{
> +	const char *opt;
> +	if (skip_prefix(arg, field, &opt)) {
> +		if (*opt == '\0') {
> +			*option = NULL;
> +			return 1;
> +		}
> +		else if (*opt == ':') {
> +			*option = ++opt;
> +			return 1;
> +		}
> +	}
> +	return 0;
> +}
> +
>  static int contents_atom_parser(const struct ref_format *format, struct used_atom *atom,
>  				const char *arg, struct strbuf *err)
>  {
> @@ -345,9 +361,8 @@ static int contents_atom_parser(const struct ref_format *format, struct used_ato
>  		atom->u.contents.option = C_SIG;
>  	else if (!strcmp(arg, "subject"))
>  		atom->u.contents.option = C_SUB;
> -	else if (skip_prefix(arg, "trailers", &arg)) {
> -		skip_prefix(arg, ":", &arg);
> -		if (trailers_atom_parser(format, atom, *arg ? arg : NULL, err))
> +	else if (check_format_field(arg, "trailers", &arg)) {
> +		if (trailers_atom_parser(format, atom, arg, err))
>  			return -1;
>  	} else if (skip_prefix(arg, "lines=", &arg)) {
>  		atom->u.contents.option = C_LINES;
Previous: Hariom Verma via GitGitGadgetNext: Junio C Hamano
Message 6 of 31 in “Fix trailers atom bug and improved tests”
  1. 0/2 Fix trailers atom bug and improved testsHariom Verma via GitGitGadget, Aug 19, 2020
  2. 1/2 t6300: unify %(trailers) and %(contents:trailers) testsHariom Verma via GitGitGadget, Aug 19, 2020
  3. Junio C HamanoAug 19, 2020
  4. Hariom vermaAug 21, 2020
  5. 2/2 ref-filter: 'contents:trailers' show error if `:` is missingHariom Verma via GitGitGadget, Aug 19, 2020
  6. Junio C HamanoAug 19, 2020
  7. Junio C HamanoAug 19, 2020
  8. Eric SunshineAug 19, 2020
  9. Junio C HamanoAug 19, 2020
  10. Hariom vermaAug 20, 2020
  11. 0/2 Fix trailers atom bug and improved testsHariom Verma via GitGitGadget, Aug 21, 2020
  12. 1/2 t6300: unify %(trailers) and %(contents:trailers) testsHariom Verma via GitGitGadget, Aug 21, 2020
  13. 2/2 ref-filter: 'contents:trailers' show error if `:` is missingHariom Verma via GitGitGadget, Aug 21, 2020
  14. Eric SunshineAug 21, 2020
  15. Junio C HamanoAug 21, 2020
  16. Hariom vermaAug 23, 2020
  17. Eric SunshineAug 24, 2020
  18. Hariom vermaAug 24, 2020
  19. Christian CouderAug 26, 2020
  20. Christian CouderAug 26, 2020
  21. Hariom vermaAug 26, 2020
  22. 0/4 [GSoC] Fix trailers atom bug and improved testsHariom Verma via GitGitGadget, Aug 21, 2020
  23. 1/4 t6300: unify %(trailers) and %(contents:trailers) testsHariom Verma via GitGitGadget, Aug 21, 2020
  24. 2/4 ref-filter: 'contents:trailers' show error if `:` is missingHariom Verma via GitGitGadget, Aug 21, 2020
  25. Eric SunshineAug 21, 2020
  26. Hariom vermaAug 21, 2020
  27. Junio C HamanoAug 21, 2020
  28. 4/4 ref-filter: using pretty.c logic for trailersHariom Verma via GitGitGadget, Aug 21, 2020
  29. 3/4 pretty.c: refactor trailer logic to `format_set_trailers_options()`Hariom Verma via GitGitGadget, Aug 21, 2020
  30. Junio C HamanoAug 21, 2020
  31. Hariom vermaAug 22, 2020

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