wishlist: git grep -r

>
> I often use "grep -r $pattern" to recursively grep a source tree. If
> that takes too long, I hit ^C and tag "git" in front of the command
> line and re-run it. git then complains "error: unknown switch `r'"
> because "git grep" is naturally recursive.
>
> Could we have "git grep -r" accept the argument for compatibility?
> Other important grep switches like "-i" are compatible, adding -r
> would improve usability.

> Requested-by: Christoph Berg <myon@debian.org>
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
>
> On Sat, Sep 29, 2018 at 4:10 PM Christoph Berg <myon@debian.org> wrote:
> >
> > I often use "grep -r $pattern" to recursively grep a source tree. If
> > that takes too long, I hit ^C and tag "git" in front of the command
> > line and re-run it. git then complains "error: unknown switch `r'"
> > because "git grep" is naturally recursive.
> >
> > Could we have "git grep -r" accept the argument for compatibility?
> > Other important grep switches like "-i" are compatible, adding -r
> > would improve usability.
>
> I don't have an opinion on this either way, it doesn't scratch my
> itch, but hey, why not. Here's a patch to implement it.
>
>  Documentation/git-grep.txt | 6 ++++++
>  builtin/grep.c             | 3 +++
>  t/t7810-grep.sh            | 8 ++++++++
>  3 files changed, 17 insertions(+)
>
> diff --git a/Documentation/git-grep.txt b/Documentation/git-grep.txt
> index a3049af1a3..a1aea8be4e 100644
> --- a/Documentation/git-grep.txt
> +++ b/Documentation/git-grep.txt
> @@ -290,6 +290,12 @@ providing this option will cause it to die.
>         Do not output matched lines; instead, exit with status 0 when
>         there is a match and with non-zero status when there isn't.
>
> +-r::
> +--recursive::
> +       This option does nothing. git-grep is always recursive. This
> +       noop option is provided for compatibility with the muscle
> +       memory of people used to grep(1).
> +
>  <tree>...::
>         Instead of searching tracked files in the working tree, search
>         blobs in the given trees.
> diff --git a/builtin/grep.c b/builtin/grep.c
> index 601f801158..02d4384225 100644
> --- a/builtin/grep.c
> +++ b/builtin/grep.c
> @@ -785,6 +785,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
>         int use_index = 1;
>         int pattern_type_arg = GREP_PATTERN_TYPE_UNSPECIFIED;
>         int allow_revs;
> +       int unused_recursive; /* this is never used */
>
>         struct option options[] = {
>                 OPT_BOOL(0, "cached", &cached,
> @@ -802,6 +803,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
>                         N_("show non-matching lines")),
>                 OPT_BOOL('i', "ignore-case", &opt.ignore_case,
>                         N_("case insensitive matching")),
> +               OPT_BOOL('r', "recursive", &unused_recursive,
> +                       N_("does nothing, git-grep is always recursive, for grep(1) muscle memory compatibility")),
>                 OPT_BOOL('w', "word-regexp", &opt.word_regexp,
>                         N_("match patterns only at word boundaries")),
>                 OPT_SET_INT('a', "text", &opt.binary,
> diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
> index be5c1bd553..c48d1fa34b 100755
> --- a/t/t7810-grep.sh
> +++ b/t/t7810-grep.sh
> @@ -469,6 +469,14 @@ do
>                 git grep --count -h -e b $H -- ab >actual &&
>                 test_cmp expected actual
>         '
> +
> +       for flag in '' ' -r' ' --recursive'
> +       do
> +               test_expect_success "grep $flag . (testing that --recursive is a noop)" '
> +                       git grep$flag . >actual &&
> +                       test_line_count = 43 actual
> +       '
> +       done
>  done
>
>  cat >expected <<EOF
> --
> 2.19.0.605.g01d371f741
>

> On Sat, Sep 29, 2018 at 4:58 PM Ævar Arnfjörð Bjarmason
> <avarab@gmail.com> wrote:
>>
>> This --recursive (-r) option does nothing, and is purely here to
>> appease people who have "grep -r ..." burned into their muscle memory.
>
> GNU grep -r recurses infinitely but Git grep also has --max-depth. How
> do these interact? My knee-jerk reaction is -r equals --max-depth=-1
> (i.e. overriding previous --mex-depth options on command line, or from
> alias)

>
>
> On Sat, Sep 29 2018, Duy Nguyen wrote:
>
> > On Sat, Sep 29, 2018 at 4:58 PM Ævar Arnfjörð Bjarmason
> > <avarab@gmail.com> wrote:
> >>
> >> This --recursive (-r) option does nothing, and is purely here to
> >> appease people who have "grep -r ..." burned into their muscle memory.
> >
> > GNU grep -r recurses infinitely but Git grep also has --max-depth. How
> > do these interact? My knee-jerk reaction is -r equals --max-depth=-1
> > (i.e. overriding previous --mex-depth options on command line, or from
> > alias)
>
> I didn't know about --max-depth, we could squash the following in to
> deal with that, but that still leaves --max-depth=123 --no-recursive as
> using depth 123, and we'd need different options parsing than OPT_BOOL
> to deal with that.

> diff --git a/builtin/grep.c b/builtin/grep.c
> index 02d4384225..2e048d9b49 100644
> --- a/builtin/grep.c
> +++ b/builtin/grep.c
> @@ -785,7 +785,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
>         int use_index = 1;
>         int pattern_type_arg = GREP_PATTERN_TYPE_UNSPECIFIED;
>         int allow_revs;
> -       int unused_recursive; /* this is never used */
> +       int recursive = 0;
>
>         struct option options[] = {
>                 OPT_BOOL(0, "cached", &cached,
> @@ -803,7 +803,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
>                         N_("show non-matching lines")),
>                 OPT_BOOL('i', "ignore-case", &opt.ignore_case,
>                         N_("case insensitive matching")),
> -               OPT_BOOL('r', "recursive", &unused_recursive,
> +               OPT_BOOL('r', "recursive", &recursive,
>                         N_("does nothing, git-grep is always recursive, for grep(1) muscle memory compatibility")),
>                 OPT_BOOL('w', "word-regexp", &opt.word_regexp,
>                         N_("match patterns only at word boundaries")),
> @@ -926,6 +926,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
>                              PARSE_OPT_STOP_AT_NON_OPTION);
>         grep_commit_pattern_type(pattern_type_arg, &opt);
>
> +       if (opt.max_depth != -1 && recursive)
> +               die(_("The --max-depth and --recursive options are incompatible"));
>         if (use_index && !startup_info->have_repository) {
>                 int fallback = 0;
>                 git_config_get_bool("grep.fallbacktonoindex", &fallback);
> diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
> index c48d1fa34b..ad25cd50f5 100755
> --- a/t/t7810-grep.sh
> +++ b/t/t7810-grep.sh
> @@ -1697,4 +1697,8 @@ test_expect_success 'grep does not report i-t-a and assume unchanged with -L' '
>         test_cmp expected actual
>  '
>
> +test_expect_success 'grep --recursive is incompatible with --max-depth' '
> +       test_must_fail git grep --recursive --max-depth=1
> +'
> +
>  test_done

> This --recursive (-r) option does nothing, and is purely here to
> appease people who have "grep -r ..." burned into their muscle memory.
>
> Requested-by: Christoph Berg <myon@debian.org>
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---

> I however do not mind if we added "--recursive" with matching
> "--no-recursive", and
> 
>  - made "--recursive" the default (obviously)
> 
>  - made "--no-recursive" a synonym to setting the recursion limit
>    to "never recurse"
> 
>  - and made "--recursive" a synonym to setting the recursion limit
>    to "infinity".
> 
> That would be more work than this patch.  But if I see "--recursive"
> advertised as a feature, and the command by default goes recursive,
> I do expect to be able to tell it not to recurse.

>
> Recognize -r and --recursive as synonyms for --max-depth=-1 for
> compatibility with GNU grep; it's still the default for git grep.
>
> This also adds --no-recursive as synonym for --max-depth=0 for free,
> which is welcome for completeness and consistency.
>
> Fix the description for --max-depth, while we're at it -- negative
> values other than -1 actually disable recursion, i.e. they are
> equivalent to --max-depth=0.
> ...
> diff --git a/builtin/grep.c b/builtin/grep.c
> index 601f801158..f6e127f0bc 100644
> --- a/builtin/grep.c
> +++ b/builtin/grep.c
> @@ -811,6 +811,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
>  			GREP_BINARY_NOMATCH),
>  		OPT_BOOL(0, "textconv", &opt.allow_textconv,
>  			 N_("process binary files with textconv filters")),
> +		OPT_SET_INT('r', "recursive", &opt.max_depth,
> +			    N_("search in subdirectories (default)"), -1),

> René Scharfe <l.s.r@web.de> writes:
>
>>
>> Recognize -r and --recursive as synonyms for --max-depth=-1 for
>> compatibility with GNU grep; it's still the default for git grep.
>>
>> This also adds --no-recursive as synonym for --max-depth=0 for free,
>> which is welcome for completeness and consistency.
>>
>> Fix the description for --max-depth, while we're at it -- negative
>> values other than -1 actually disable recursion, i.e. they are
>> equivalent to --max-depth=0.
>> ...
>> diff --git a/builtin/grep.c b/builtin/grep.c
>> index 601f801158..f6e127f0bc 100644
>> --- a/builtin/grep.c
>> +++ b/builtin/grep.c
>> @@ -811,6 +811,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
>>  			GREP_BINARY_NOMATCH),
>>  		OPT_BOOL(0, "textconv", &opt.allow_textconv,
>>  			 N_("process binary files with textconv filters")),
>> +		OPT_SET_INT('r', "recursive", &opt.max_depth,
>> +			    N_("search in subdirectories (default)"), -1),
>
> Wow.
>
> I didn't think of this trick to let OPT_SET_INT() to grok --no-* and
> set the variable to 0.  Being able to do this without a custom
> callback is certainly very nice.
>
> The patch looks good.

>
> This --recursive (-r) option does nothing, and is purely here to
> appease people who have "grep -r ..." burned into their muscle memory.
>
> Requested-by: Christoph Berg <myon@debian.org>
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
>
> On Sat, Sep 29, 2018 at 4:10 PM Christoph Berg <myon@debian.org> wrote:
> >
> > I often use "grep -r $pattern" to recursively grep a source tree. If
> > that takes too long, I hit ^C and tag "git" in front of the command
> > line and re-run it. git then complains "error: unknown switch `r'"
> > because "git grep" is naturally recursive.
> >
> > Could we have "git grep -r" accept the argument for compatibility?
> > Other important grep switches like "-i" are compatible, adding -r
> > would improve usability.
>
> I don't have an opinion on this either way, it doesn't scratch my
> itch, but hey, why not. Here's a patch to implement it.
>
>  Documentation/git-grep.txt | 6 ++++++
>  builtin/grep.c             | 3 +++
>  t/t7810-grep.sh            | 8 ++++++++
>  3 files changed, 17 insertions(+)
>
> diff --git a/Documentation/git-grep.txt b/Documentation/git-grep.txt
> index a3049af1a3..a1aea8be4e 100644
> --- a/Documentation/git-grep.txt
> +++ b/Documentation/git-grep.txt
> @@ -290,6 +290,12 @@ providing this option will cause it to die.
>         Do not output matched lines; instead, exit with status 0 when
>         there is a match and with non-zero status when there isn't.
>
> +-r::
> +--recursive::
> +       This option does nothing. git-grep is always recursive. This
> +       noop option is provided for compatibility with the muscle
> +       memory of people used to grep(1).

> Stefan Beller <sbeller@google.com> writes:
> 
> > git-grep is always file/tree recursive, but there is --recurse-submodules
> > which is off by default. Instead of providing a short alias to a noop,
> > we could use -r for submodules. (And if you happen to have no
> > submodules, this is a noop for you)
> 
> I am not sure if it is an overall win for those who do have and use
> submodules to easily be able to go recursive with a short-and-sweet
> 'r', or even they want to work inside one project at a time most of
> the time.  If the latter, then using 'r' for recurse-submodules is
> going to be a mistake (besides, other commands that have 'recursive'
> typically use 'r' for its shorthand,and 'r' does not stand for
> 'recurse-submodules' for them).

>
> Junio C Hamano wrote 2018-10-05 1:19 (-0700):
> > Stefan Beller <sbeller@google.com> writes:
> >
> > > git-grep is always file/tree recursive, but there is --recurse-submodules
> > > which is off by default. Instead of providing a short alias to a noop,
> > > we could use -r for submodules. (And if you happen to have no
> > > submodules, this is a noop for you)
> >
> > I am not sure if it is an overall win for those who do have and use
> > submodules to easily be able to go recursive with a short-and-sweet
> > 'r', or even they want to work inside one project at a time most of
> > the time.  If the latter, then using 'r' for recurse-submodules is
> > going to be a mistake (besides, other commands that have 'recursive'
> > typically use 'r' for its shorthand,and 'r' does not stand for
> > 'recurse-submodules' for them).
>
> Personally I would welcome a shorthand for --recurse-submodules,
> especially if --r^I no longer completes to this.