diff-options.txt: correct command syntax
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Message ID 20200202192226.29176-1-adam@dinwoodie.org
State New
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  • diff-options.txt: correct command syntax
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Commit Message

Adam Dinwoodie Feb. 2, 2020, 7:22 p.m. UTC
Change the example arguments in the description of the -G diff argument
to be consistent throughout the description.

Signed-off-by: Adam Dinwoodie <adam@dinwoodie.org>
---
 Documentation/diff-options.txt | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Martin Ågren Feb. 2, 2020, 7:45 p.m. UTC | #1
Hi Adam,

On Sun, 2 Feb 2020 at 20:24, Adam Dinwoodie <adam@dinwoodie.org> wrote:
>
> Change the example arguments in the description of the -G diff argument
> to be consistent throughout the description.
>
> Signed-off-by: Adam Dinwoodie <adam@dinwoodie.org>
> ---
>  Documentation/diff-options.txt | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
> index 09faee3b44..84a74cb2da 100644
> --- a/Documentation/diff-options.txt
> +++ b/Documentation/diff-options.txt
> @@ -561,19 +561,19 @@ Binary files are searched as well.
>  -G<regex>::
>         Look for differences whose patch text contains added/removed
>         lines that match <regex>.
>  +
>  To illustrate the difference between `-S<regex> --pickaxe-regex` and
>  `-G<regex>`, consider a commit with the following diff in the same
>  file:
>  +
>  ----
>  +    return !regexec(regexp, two->ptr, 1, &regmatch, 0);
>  ...
>  -    hit = !regexec(regexp, mf2.ptr, 1, &regmatch, 0);
>  ----
>  +
> -While `git log -G"regexec\(regexp"` will show this commit, `git log
> --S"regexec\(regexp" --pickaxe-regex` will not (because the number of
> +While `git log -G<regex>` will show this commit, `git log
> +-S<regex> --pickaxe-regex` will not (because the number of
>  occurrences of that string did not change).

I don't think this is correct. "<regex>" is a placeholder and this
example wants to use a real-world regex instead of the placeholder.
Maybe this could be made clearer by having an example that does not try
to grep in regex-code using the regex "regexec\(regexp".

Maybe instead of "regexec", "regexp" and "regmatch", this example could
use words from some other domain? Would something like this be clearer?

 To illustrate the difference between `-S<regex> --pickaxe-regex` and
 `-G<regex>`, consider a commit with the following diff in the same
 file:
 +
 ----
 +    return !frotz(nitfol, two->ptr, 1, 0);
 ...
 -    hit = !frotz(nitfol, mf2.ptr, 1, 0);
 ----
 +
 While `git log -G"frotz\(nitfol"` will show this commit, `git log
 -S"frotz\(nitfol" --pickaxe-regex` will not (because the number of
 occurrences of that string did not change).

BTW, I wonder what "in the same file" tries to say -- my hunch is we
could drop those words without any loss of correctness or readability.
Would you agree?

Martin
Adam Dinwoodie Feb. 2, 2020, 8:47 p.m. UTC | #2
On Sunday 02 February 2020 at 08:45 pm +0100, Martin Ågren wrote:
> Hi Adam,
> 
> On Sun, 2 Feb 2020 at 20:24, Adam Dinwoodie <adam@dinwoodie.org> wrote:
> >
> > Change the example arguments in the description of the -G diff argument
> > to be consistent throughout the description.
> >
> > Signed-off-by: Adam Dinwoodie <adam@dinwoodie.org>
> > ---
> >  Documentation/diff-options.txt | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
> > index 09faee3b44..84a74cb2da 100644
> > --- a/Documentation/diff-options.txt
> > +++ b/Documentation/diff-options.txt
> > @@ -561,19 +561,19 @@ Binary files are searched as well.
> >  -G<regex>::
> >         Look for differences whose patch text contains added/removed
> >         lines that match <regex>.
> >  +
> >  To illustrate the difference between `-S<regex> --pickaxe-regex` and
> >  `-G<regex>`, consider a commit with the following diff in the same
> >  file:
> >  +
> >  ----
> >  +    return !regexec(regexp, two->ptr, 1, &regmatch, 0);
> >  ...
> >  -    hit = !regexec(regexp, mf2.ptr, 1, &regmatch, 0);
> >  ----
> >  +
> > -While `git log -G"regexec\(regexp"` will show this commit, `git log
> > --S"regexec\(regexp" --pickaxe-regex` will not (because the number of
> > +While `git log -G<regex>` will show this commit, `git log
> > +-S<regex> --pickaxe-regex` will not (because the number of
> >  occurrences of that string did not change).
> 
> I don't think this is correct. "<regex>" is a placeholder and this
> example wants to use a real-world regex instead of the placeholder.
> Maybe this could be made clearer by having an example that does not try
> to grep in regex-code using the regex "regexec\(regexp".
> 
> Maybe instead of "regexec", "regexp" and "regmatch", this example could
> use words from some other domain? Would something like this be clearer?
> 
>  To illustrate the difference between `-S<regex> --pickaxe-regex` and
>  `-G<regex>`, consider a commit with the following diff in the same
>  file:
>  +
>  ----
>  +    return !frotz(nitfol, two->ptr, 1, 0);
>  ...
>  -    hit = !frotz(nitfol, mf2.ptr, 1, 0);
>  ----
>  +
>  While `git log -G"frotz\(nitfol"` will show this commit, `git log
>  -S"frotz\(nitfol" --pickaxe-regex` will not (because the number of
>  occurrences of that string did not change).

Ah, thank you!  I had completely misread what these examples were trying
to achieve.  I think your example (or indeed anything from a different
domain) would have avoided me getting confused in the first place.
Although I'm much less fussed now I realise the problem here was
entirely my understanding rather than an error in the docs.

> BTW, I wonder what "in the same file" tries to say -- my hunch is we
> could drop those words without any loss of correctness or readability.
> Would you agree?

I think "in the same file" is meaningful here: as I understand it both
forms would find a commit that removed a line from one file and added it
back to a _different_ file, but only the -G form would pick it when
removed and added lines are in the same file.

Adam
Martin Ågren Feb. 3, 2020, 6:24 a.m. UTC | #3
On Sun, 2 Feb 2020 at 21:47, Adam Dinwoodie <adam@dinwoodie.org> wrote:
> On Sunday 02 February 2020 at 08:45 pm +0100, Martin Ågren wrote:
> > On Sun, 2 Feb 2020 at 20:24, Adam Dinwoodie <adam@dinwoodie.org> wrote:
>
> Ah, thank you!  I had completely misread what these examples were trying
> to achieve.  I think your example (or indeed anything from a different
> domain) would have avoided me getting confused in the first place.
> Although I'm much less fussed now I realise the problem here was
> entirely my understanding rather than an error in the docs.
>
> > BTW, I wonder what "in the same file" tries to say -- my hunch is we
> > could drop those words without any loss of correctness or readability.
> > Would you agree?
>
> I think "in the same file" is meaningful here: as I understand it both
> forms would find a commit that removed a line from one file and added it
> back to a _different_ file, but only the -G form would pick it when
> removed and added lines are in the same file.

You're right, it is needed. At least the way the example is given now,
where there's some arbitrary amount of left-out context between the "+"
and the "-" line, it's necessary to limit that by saying that it's in
the same file. Because this is an example, we're allowed to make it as
concrete as we see fit. For example:

 To illustrate the difference between `-S<regex> --pickaxe-regex` and
 `-G<regex>`, consider a commit with the following diff:
 +
 ----
 -    hit = !frotz(nitfol, mf2.ptr, 1, 0);
 +    return !frotz(nitfol, two->ptr, 1, 0);
 ----
 +
 While `git log -G"frotz\(nitfol"` will show this commit, `git log
 -S"frotz\(nitfol" --pickaxe-regex` will not (because the number of
 occurrences of that string did not change).

Or does that make it too specific, i.e., could this give readers the
wrong impression that -G and/or -S and/or the difference explained here
only apply to such "trivial" cases?

Martin

Patch
diff mbox series

diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 09faee3b44..84a74cb2da 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -561,19 +561,19 @@  Binary files are searched as well.
 -G<regex>::
 	Look for differences whose patch text contains added/removed
 	lines that match <regex>.
 +
 To illustrate the difference between `-S<regex> --pickaxe-regex` and
 `-G<regex>`, consider a commit with the following diff in the same
 file:
 +
 ----
 +    return !regexec(regexp, two->ptr, 1, &regmatch, 0);
 ...
 -    hit = !regexec(regexp, mf2.ptr, 1, &regmatch, 0);
 ----
 +
-While `git log -G"regexec\(regexp"` will show this commit, `git log
--S"regexec\(regexp" --pickaxe-regex` will not (because the number of
+While `git log -G<regex>` will show this commit, `git log
+-S<regex> --pickaxe-regex` will not (because the number of
 occurrences of that string did not change).
 +
 Unless `--text` is supplied patches of binary files without a textconv