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From: Brandon Williams <bmwill@google.com>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: git@vger.kernel.org, "Junio C Hamano" <gitster@pobox.com>,
	"Jeff King" <peff@peff.net>,
	"Jeffrey Walton" <noloader@gmail.com>,
	"Michał Kiedrowicz" <michal.kiedrowicz@gmail.com>,
	"J Smith" <dark.panda@gmail.com>,
	"Victor Leschuk" <vleschuk@gmail.com>,
	"Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>,
	"Fredrik Kuivinen" <frekui@gmail.com>,
	"Zoltán Herczeg" <hzmester@freemail.hu>
Subject: Re: [PATCH v3 03/18] grep: submodule-related case statements should die if new fields are added
Date: Thu, 20 Apr 2017 15:20:16 -0700	[thread overview]
Message-ID: <20170420222016.GJ142567@google.com> (raw)
In-Reply-To: <20170420212345.7408-4-avarab@gmail.com>

On 04/20, Ævar Arnfjörð Bjarmason wrote:
> Change two case statements added in commit 0281e487fd ("grep:
> optionally recurse into submodules", 2016-12-16) so that they die if
> new GREP_PATTERN_* enum fields are added without updating them.
> 
> These case statements currently check for an exhaustive list of
> fields, but if a new field is added it's easy to introduce a bug here
> where the code will start subtly doing the wrong thing, e.g. if a new
> pattern type is added we'll fall through to
> GREP_PATTERN_TYPE_UNSPECIFIED, i.e. the "basic" POSIX regular
> expressions.
> 
> This should arguably be done for the switch(opt->binary)
> case-statement as well, but isn't trivial to add since that code isn't
> currently working with an exhaustive list.

I was under the impression that the code wouldn't compile if there is a
missing enum field in the switch statement.  Does it instead silently
fall through?  I would choose not compiling over a die statement that may
not be caught during the development of a new series.

> 
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
>  builtin/grep.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/builtin/grep.c b/builtin/grep.c
> index 3ffb5b4e81..be3dbd6957 100644
> --- a/builtin/grep.c
> +++ b/builtin/grep.c
> @@ -495,6 +495,8 @@ static void compile_submodule_options(const struct grep_opt *opt,
>  		break;
>  	case GREP_PATTERN_TYPE_UNSPECIFIED:
>  		break;
> +	default:
> +		die("BUG: Added a new grep pattern type without updating switch statement");
>  	}
>  
>  	for (pattern = opt->pattern_list; pattern != NULL;
> @@ -515,6 +517,8 @@ static void compile_submodule_options(const struct grep_opt *opt,
>  		case GREP_PATTERN_BODY:
>  		case GREP_PATTERN_HEAD:
>  			break;
> +		default:
> +			die("BUG: Added a new grep token type without updating case statement");
>  		}
>  	}
>  
> -- 
> 2.11.0
> 

-- 
Brandon Williams

  reply	other threads:[~2017-04-20 22:20 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-20 21:23 [PATCH v3 00/18] PCRE v1 improvements & PCRE v2 support Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 01/18] grep: amend submodule recursion test in preparation for rx engine testing Ævar Arnfjörð Bjarmason
2017-04-20 22:22   ` Brandon Williams
2017-04-20 21:23 ` [PATCH v3 02/18] grep: add tests for grep pattern types being passed to submodules Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 03/18] grep: submodule-related case statements should die if new fields are added Ævar Arnfjörð Bjarmason
2017-04-20 22:20   ` Brandon Williams [this message]
2017-04-20 22:27     ` Jeff King
2017-04-20 21:23 ` [PATCH v3 04/18] grep: remove redundant regflags assignment under PCRE Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 05/18] Makefile & configure: reword outdated comment about PCRE Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 06/18] grep: add a test for backreferences in PCRE patterns Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 07/18] log: add exhaustive tests for pattern style options & config Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 08/18] log: add -P as a synonym for --perl-regexp Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 09/18] grep & rev-list doc: stop promising libpcre " Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 10/18] grep: make grep.patternType=[pcre|pcre1] a synonym for "perl" Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 11/18] test-lib: rename the LIBPCRE prerequisite to PCRE Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 12/18] grep: change the internal PCRE macro names to be PCRE1 Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 13/18] grep: change the internal PCRE code & header " Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 14/18] perf: add a performance comparison test of grep -E and -P Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 15/18] grep: add support for the PCRE v1 JIT API Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 16/18] grep: add support for PCRE v2 Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 17/18] grep: remove support concurrent use of both PCRE v1 & v2 Ævar Arnfjörð Bjarmason
2017-04-20 21:23 ` [PATCH v3 18/18] Makefile & configure: make PCRE v2 the default PCRE implementation Ævar Arnfjörð Bjarmason

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