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grep/log: remove hidden --debug and --grep-debug options

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Remove the hidden "grep --debug" and "log --grep-debug" options added
in 17bf35a3c7 (grep: teach --debug option to dump the parse tree,
2012-09-13).

At the time these options seem to have been intended to go along with
a documentation discussion and to help the author of relevant tests to
perform ad-hoc debugging on them[1].

Reasons to want this gone:

 1. They were never documented, and the only (rather trivial) use of
    them in our own codebase for testing is something I removed back
    in e01b4dab01 (grep: change non-ASCII -i test to stop using
    --debug, 2017-05-20).

 2. Googling around doesn't show any in-the-wild uses I could dig up,
    and on the Git ML the only mentions after the original discussion
    seem to have been when they came up in unrelated diff contexts, or
    that test commit of mine.

 3. An exception to that is c581e4a749 (grep: under --debug, show
    whether PCRE JIT is enabled, 2019-08-18) where we added the
    ability to dump out when PCREv2 has the JIT in effect.

    The combination of that and my earlier b65abcafc7 (grep: use PCRE
    v2 for optimized fixed-string search, 2019-07-01) means Git prints
    this out in its most common in-the-wild configuration:

        $ git log  --grep-debug --grep=foo --grep=bar --grep=baz --all-match
        pcre2_jit_on=1
        pcre2_jit_on=1
        pcre2_jit_on=1
        [all-match]
        (or
         pattern_body<body>foo
         (or
          pattern_body<body>bar
          pattern_body<body>baz
         )
        )

        $ git grep --debug \( -e foo --and -e bar \) --or -e baz
        pcre2_jit_on=1
        pcre2_jit_on=1
        pcre2_jit_on=1
        (or
         (and
          patternfoo
          patternbar
         )
         patternbaz
        )

I.e. for each pattern we're considering for the and/or/--all-match
etc. debugging we'll now diligently spew out another identical line
saying whether the PCREv2 JIT is on or not.

I think that nobody's complained about that rather glaringly obviously
bad output says something about how much this is used, i.e. it's
not.

The need for this debugging aid for the composed grep/log patterns
seems to have passed, and the desire to dump the JIT config seems to
have been another one-off around the time we had JIT-related issues on
the PCREv2 codepath. That the original author of this debugging
facility seemingly hasn't noticed the bad output since then[2] is
probably some indicator.

1. https://lore.kernel.org/git/cover.1347615361.git.git@drmicha.warpmail.net/
2. https://lore.kernel.org/git/xmqqk1b8x0ac.fsf@gitster-ct.c.googlers.com/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Ævar Arnfjörð Bjarmason
2021-01-26 00:36:51 +01:00
committed by Junio C Hamano
parent 71ca53e812
commit 15c9649730
4 changed files with 2 additions and 107 deletions
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1
grep.h
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@ -136,7 +136,6 @@ struct grep_opt {
int word_regexp;
int fixed;
int all_match;
int debug;
#define GREP_BINARY_DEFAULT 0
#define GREP_BINARY_NOMATCH 1
#define GREP_BINARY_TEXT 2