Re: [PATCH v2 18/29] grep: catch a missing enum in switch statement
- Date: Mon, 15 May 2017 14:50:29 +0900
- From: Junio C Hamano <gitster@xxxxxxxxx>
- Subject: Re: [PATCH v2 18/29] grep: catch a missing enum in switch statement
Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> writes:
> Add a die(...) to a default case for the switch statement selecting
> between grep pattern types under --recurse-submodules.
> Normally this would be caught by -Wswitch, but the grep_pattern_type
> type is converted to int by going through parse_options(). Changing
> the argument type passed to compile_submodule_options() won't work,
> the value will just get coerced. The -Wswitch-default warning will
> warn about it, but that produces a lot of noise across the codebase,
> this potential issue would be drowned in that noise.
> Thus catching this at runtime is the least worst option. This won't
least bad, I guess?
> ever trigger in practice, but if a new pattern type were to be added
> this catches an otherwise silent bug during development.
Good future-proofing. When this and Peff's "BUG" thing both
graduates, we can turn this into a BUG, I think.
> See commit 0281e487fd ("grep: optionally recurse into submodules",
> 2016-12-16) for the initial addition of this code.
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>
> builtin/grep.c | 2 ++
> 1 file changed, 2 insertions(+)
> diff --git a/builtin/grep.c b/builtin/grep.c
> index 3ffb5b4e81..a191e2976b 100644
> --- a/builtin/grep.c
> +++ b/builtin/grep.c
> @@ -495,6 +495,8 @@ static void compile_submodule_options(const struct grep_opt *opt,
> case GREP_PATTERN_TYPE_UNSPECIFIED:
> + default:
> + die("BUG: Added a new grep pattern type without updating switch statement");
> for (pattern = opt->pattern_list; pattern != NULL;