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Re: [PATCH v4 05/19] grep: remove redundant `regflags &= ~REG_EXTENDED` assignments

From
Junio C Hamano <gitster@pobox.com>
Date
Apr 26, 2017, 04:50 UTC
Message-ID
<xmqq4lxbsrfj.fsf@gitster.mtv.corp.google.com>
In-Reply-To
<20170425210548.24612-6-avarab@gmail.com>
Ævar Arnfjörð Bjarmason  <avarab@gmail.com> writes:
Show 7 quoted lines
> Remove redundant assignments to the "regflags" variable. There are no
> code paths that have previously set the regflags to anything, and
> certainly not to `|= REG_EXTENDED`.
>
> This code gave the impression that it had to reset its environment,
> but it doesn't. This dates back to the initial introduction of
> git-grep in commit 5010cb5fcc ("built-in "git grep"", 2006-04-30).

As long as nobody calls grep_commit_pattern_type() more than once while interpreting something like "grep -E -G -P -F -G" (i.e. "I cannot quite decide which pattern type I want to give..."), this change should be safe.

This made me wonder if we should be doing "opt->regflags = REG_EXTENDED" for ERE from the same "this is only called once" reasoning, but regflags is a collection of bits, and presumably bits other than REG_EXTENDED can be set before the control reaches grep_commit_pattern_type(), so that one must stay as-is, i.e. "opt->regflags |= REG_EXTENDED".

Thanks.
Previous: Ævar Arnfjörð BjarmasonNext: Junio C Hamano
Message 7 of 24 in “PCRE v1 improvements & PCRE v2 support”
  1. 00/19 PCRE v1 improvements & PCRE v2 supportÆvar Arnfjörð Bjarmason, Apr 25, 2017
  2. 01/19 grep: amend submodule recursion test in preparation for rx engine testingÆvar Arnfjörð Bjarmason, Apr 25, 2017
  3. 02/19 grep: add tests for grep pattern types being passed to submodulesÆvar Arnfjörð Bjarmason, Apr 25, 2017
  4. 03/19 grep: submodule-related case statements should die if new fields are addedÆvar Arnfjörð Bjarmason, Apr 25, 2017
  5. 04/19 grep: remove redundant regflags assignment under PCREÆvar Arnfjörð Bjarmason, Apr 25, 2017
  6. 05/19 grep: remove redundant `regflags &= ~REG_EXTENDED` assignmentsÆvar Arnfjörð Bjarmason, Apr 25, 2017
  7. Junio C HamanoApr 26, 2017
  8. Junio C HamanoApr 26, 2017
  9. 05/19 grep: remove redundant `regflags &= ~REG_EXTENDED` assignmentsÆvar Arnfjörð Bjarmason, Apr 26, 2017
  10. Junio C HamanoApr 27, 2017
  11. 06/19 Makefile & configure: reword outdated comment about PCREÆvar Arnfjörð Bjarmason, Apr 25, 2017
  12. 07/19 grep: add a test for backreferences in PCRE patternsÆvar Arnfjörð Bjarmason, Apr 25, 2017
  13. 09/19 log: add -P as a synonym for --perl-regexpÆvar Arnfjörð Bjarmason, Apr 25, 2017
  14. 08/19 log: add exhaustive tests for pattern style options & configÆvar Arnfjörð Bjarmason, Apr 25, 2017
  15. 10/19 grep & rev-list doc: stop promising libpcre for --perl-regexpÆvar Arnfjörð Bjarmason, Apr 25, 2017
  16. 12/19 test-lib: rename the LIBPCRE prerequisite to PCREÆvar Arnfjörð Bjarmason, Apr 25, 2017
  17. 13/19 grep: change the internal PCRE macro names to be PCRE1Ævar Arnfjörð Bjarmason, Apr 25, 2017
  18. 14/19 grep: change the internal PCRE code & header names to be PCRE1Ævar Arnfjörð Bjarmason, Apr 25, 2017
  19. 15/19 perf: add a performance comparison test of grep -E and -PÆvar Arnfjörð Bjarmason, Apr 25, 2017
  20. 11/19 grep: make grep.patternType=[pcre|pcre1] a synonym for "perl"Ævar Arnfjörð Bjarmason, Apr 25, 2017
  21. 16/19 grep: add support for the PCRE v1 JIT APIÆvar Arnfjörð Bjarmason, Apr 25, 2017
  22. 17/19 grep: add support for PCRE v2Ævar Arnfjörð Bjarmason, Apr 25, 2017
  23. 18/19 grep: remove support for concurrent use of both PCRE v1 & v2Ævar Arnfjörð Bjarmason, Apr 25, 2017
  24. 19/19 Makefile & configure: make PCRE v2 the default PCRE implementationÆvar Arnfjörð Bjarmason, Apr 25, 2017

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