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[PATCH v4 01/31] Makefile & configure: reword inaccurate comment about PCRE

From
Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date
May 25, 2017, 19:45 UTC
Message-ID
<20170525194535.9324-2-avarab@gmail.com>
In-Reply-To
<20170525194535.9324-1-avarab@gmail.com>

Reword an outdated & inaccurate comment which suggests that only git-grep can use PCRE.

This comment was added back when PCRE support was initially added in commit 63e7e9d8b6 ("git-grep: Learn PCRE", 2011-05-09), and was true at the time.

It hasn't been telling the full truth since git-log learned to use PCRE with --grep in commit 727b6fc3ed ("log --grep: accept --basic-regexp and --perl-regexp", 2012-10-03), and more importantly is likely to get more inaccurate over time as more use is made of PCRE in other areas.

Reword it to be more future-proof, and to more clearly explain that this enables user-initiated runtime behavior.

Copy/pasting this so much in configure.ac is lame, these Makefile-like flags aren't even used by autoconf, just the corresponding --with[out]-* options. But copy/pasting the comments that make sense for the Makefile to configure.ac where they make less sense is the pattern everything else follows in that file. I'm not going to war against that as part of this change, just following the existing pattern.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 Makefile     |  6 ++++--
 configure.ac | 12 ++++++++----
 2 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/Makefile b/Makefile
index e35542e631..eedadb8056 100644
--- a/Makefile
+++ b/Makefile
@@ -24,8 +24,10 @@ all::
 # Define NO_OPENSSL environment variable if you do not have OpenSSL.
 # This also implies BLK_SHA1.
 #
-# Define USE_LIBPCRE if you have and want to use libpcre. git-grep will be
-# able to use Perl-compatible regular expressions.
+# Define USE_LIBPCRE if you have and want to use libpcre. Various
+# commands such as log and grep offer runtime options to use
+# Perl-compatible regular expressions instead of standard or extended
+# POSIX regular expressions.
 #
 # Define LIBPCREDIR=/foo/bar if your libpcre header and library files are in
 # /foo/bar/include and /foo/bar/lib directories.
diff --git a/configure.ac b/configure.ac
index 128165529f..deeb968daa 100644
--- a/configure.ac
+++ b/configure.ac
@@ -250,8 +250,10 @@ AS_HELP_STRING([--with-openssl],[use OpenSSL library (default is YES)])
 AS_HELP_STRING([],              [ARG can be prefix for openssl library and headers]),
 GIT_PARSE_WITH([openssl]))
 
-# Define USE_LIBPCRE if you have and want to use libpcre. git-grep will be
-# able to use Perl-compatible regular expressions.
+# Define USE_LIBPCRE if you have and want to use libpcre. Various
+# commands such as log and grep offer runtime options to use
+# Perl-compatible regular expressions instead of standard or extended
+# POSIX regular expressions.
 #
 # Define LIBPCREDIR=/foo/bar if your libpcre header and library files are in
 # /foo/bar/include and /foo/bar/lib directories.
@@ -499,8 +501,10 @@ GIT_CONF_SUBST([NEEDS_SSL_WITH_CRYPTO])
 GIT_CONF_SUBST([NO_OPENSSL])
 
 #
-# Define USE_LIBPCRE if you have and want to use libpcre. git-grep will be
-# able to use Perl-compatible regular expressions.
+# Define USE_LIBPCRE if you have and want to use libpcre. Various
+# commands such as log and grep offer runtime options to use
+# Perl-compatible regular expressions instead of standard or extended
+# POSIX regular expressions.
 #
 
 if test -n "$USE_LIBPCRE"; then

-- 
2.13.0.303.g4ebf302169
Previous: Ævar Arnfjörð BjarmasonNext: Ævar Arnfjörð Bjarmason
Message 2 of 32 in “Easy to review grep & pre-PCRE changes”
  1. 00/31 Easy to review grep & pre-PCRE changesÆvar Arnfjörð Bjarmason, May 25, 2017
  2. 01/31 Makefile & configure: reword inaccurate comment about PCREÆvar Arnfjörð Bjarmason, May 25, 2017
  3. 02/31 grep & rev-list doc: stop promising libpcre for --perl-regexpÆvar Arnfjörð Bjarmason, May 25, 2017
  4. 04/31 log: add exhaustive tests for pattern style options & configÆvar Arnfjörð Bjarmason, May 25, 2017
  5. 03/31 test-lib: rename the LIBPCRE prerequisite to PCREÆvar Arnfjörð Bjarmason, May 25, 2017
  6. 05/31 log: make --regexp-ignore-case work with --perl-regexpÆvar Arnfjörð Bjarmason, May 25, 2017
  7. 07/31 grep: add a test for backreferences in PCRE patternsÆvar Arnfjörð Bjarmason, May 25, 2017
  8. 08/31 grep: change non-ASCII -i test to stop using --debugÆvar Arnfjörð Bjarmason, May 25, 2017
  9. 06/31 grep: add a test asserting that --perl-regexp dies when !PCREÆvar Arnfjörð Bjarmason, May 25, 2017
  10. 09/31 grep: add tests for --threads=N and grep.threadsÆvar Arnfjörð Bjarmason, May 25, 2017
  11. 10/31 grep: amend submodule recursion test for regex engine testingÆvar Arnfjörð Bjarmason, May 25, 2017
  12. 11/31 grep: add tests for grep pattern types being passed to submodulesÆvar Arnfjörð Bjarmason, May 25, 2017
  13. 12/31 grep: add a test helper function for less verbose -f \0 testsÆvar Arnfjörð Bjarmason, May 25, 2017
  14. 13/31 grep: prepare for testing binary regexes containing rx metacharactersÆvar Arnfjörð Bjarmason, May 25, 2017
  15. 14/31 grep: add tests to fix blind spots with \0 patternsÆvar Arnfjörð Bjarmason, May 25, 2017
  16. 16/31 perf: emit progress output when unpacking & buildingÆvar Arnfjörð Bjarmason, May 25, 2017
  17. 18/31 perf: add a comparison test of grep regex engines with -FÆvar Arnfjörð Bjarmason, May 25, 2017
  18. 17/31 perf: add a comparison test of grep regex enginesÆvar Arnfjörð Bjarmason, May 25, 2017
  19. 15/31 perf: add a GIT_PERF_MAKE_COMMAND for when *_MAKE_OPTS won't doÆvar Arnfjörð Bjarmason, May 25, 2017
  20. 19/31 perf: add a comparison test of log --grep regex enginesÆvar Arnfjörð Bjarmason, May 25, 2017
  21. 20/31 perf: add a comparison test of log --grep regex engines with -FÆvar Arnfjörð Bjarmason, May 25, 2017
  22. 24/31 grep: change the internal PCRE macro names to be PCRE1Ævar Arnfjörð Bjarmason, May 25, 2017
  23. 23/31 grep: factor test for \0 in grep patterns into a functionÆvar Arnfjörð Bjarmason, May 25, 2017
  24. 21/31 grep: catch a missing enum in switch statementÆvar Arnfjörð Bjarmason, May 25, 2017
  25. 22/31 grep: remove redundant regflags assignmentsÆvar Arnfjörð Bjarmason, May 25, 2017
  26. 28/31 pack-objects & index-pack: add test for --threads warningÆvar Arnfjörð Bjarmason, May 25, 2017
  27. 30/31 grep: given --threads with NO_PTHREADS=YesPlease, warnÆvar Arnfjörð Bjarmason, May 25, 2017
  28. 25/31 grep: change internal *pcre* variable & function names to be *pcre1*Ævar Arnfjörð Bjarmason, May 25, 2017
  29. 31/31 grep: assert that threading is enabled when calling grep_{lock,unlock}Ævar Arnfjörð Bjarmason, May 25, 2017
  30. 29/31 pack-objects: fix buggy warning about threadsÆvar Arnfjörð Bjarmason, May 25, 2017
  31. 27/31 test-lib: add a PTHREADS prerequisiteÆvar Arnfjörð Bjarmason, May 25, 2017
  32. 26/31 grep: move is_fixed() earlier to avoid forward declarationÆvar Arnfjörð Bjarmason, May 25, 2017

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