Re: Potential bug in --color-words output

[Stefan Beller <stefanbeller@gmail.com>]

Hi,

in my copy of git there is:

----
git % git grep --line-number --no-color  color-words

Documentation/RelNotes/1.5.4.txt:377: * "git diff --color-words"
colored context lines in a wrong color.

Documentation/RelNotes/1.6.2.txt:100:* The definition of what
constitutes a word for "git diff --color-words"

Documentation/RelNotes/1.6.5.3.txt:23: * "git diff --color-words -U0"
didn't work correctly.

Documentation/RelNotes/1.7.2.txt:64: * "git diff --word-diff=<mode>"
extends the existing "--color-words"

Documentation/RelNotes/1.7.2.txt:141: * "git diff --graph" works
better with "--color-words" and other options

Documentation/diff-options.txt:475:--color-words[=<regex>]::

contrib/completion/git-completion.bash:1718:
--no-color --color-words --no-renames --check

contrib/diff-highlight/README:9:You can use "--color-words" to
highlight only the changed portions of

diff.c:1914: * '--color-words' algorithm can be described as:

diff.c:1929: * For '--graph' to work with '--color-words', we need to
output the graph prefix

diff.c:2138:/* In "color-words" mode, show word-diff of words
accumulated in the buffer */

diff.c:5566:            OPT_CALLBACK_F(0, "color-words", options, N_("<regex>"),

gitk-git/gitk:207:            "--color-words*" - "--word-diff=color" {

t/t4034-diff-words.sh:70:               word_diff --color-words

t/t4034-diff-words.sh:100:      word_diff --color-words &&

t/t4034-diff-words.sh:180:      word_diff --color-words --unified=0

t/t4034-diff-words.sh:185:      word_diff --color-words="[a-z]+"

t/t4034-diff-words.sh:190:      word_diff --color-words="[a-z${LF}]*"

t/t4034-diff-words.sh:203:      word_diff --color-words="[a-z]+"

t/t4034-diff-words.sh:208:      word_diff --color-words

t/t4034-diff-words.sh:217:      word_diff --color-words="[a-z]+"

t/t4034-diff-words.sh:240:      word_diff --color-words

t/t4034-diff-words.sh:262:      word_diff --color-words

t/t4034-diff-words.sh:278:      word_diff --color-words="a+"

t/t4034-diff-words.sh:294:      word_diff --color-words=.
----


So there are tests in t/t4034-diff-words.sh and probably around
diff.c:1914- diff.c:2138

Best,
Stefan


Am Mo., 7. Nov. 2022 um 12:43 Uhr schrieb Simeon Krastnikov
<skrastnikov@gmail.com>:
>
> Hi Junio, Phillip, and Stefan,
>
> I apologize for forwarding this to you personally, but based on the recent commit history, I figured that you would be the right persons to ask about this.
>
> Sorry again, if you consider this to be spam.
>
> Best,
>
> Simeon
>
>
>
> -------- Forwarded Message --------
> Subject: Potential bug in --color-words output
> Date: Fri, 28 Oct 2022 23:08:09 +0200
> From: Simeon Krastnikov <skrastnikov@gmail.com>
> To: git@vger.kernel.org
>
>
> Hello,
>
> Given an initial file with the contents "not to be", which I then change to "to be", the output of 'git diff --color-words', is
>
>   notto be
>
> with the first three letters colored red. To me this seems incorrect as it implies, or at least misleadingly suggests, that there was no space between "not" and "to" in the original file. (Even though in that case the output is actually "nottoto be" with the "notto" in red and "to" in green.)
>
> If instead I start with a file with contents "to be", which I then change to "not to be", then the output is as expected:
>
>   not to be
>
> (First three letters colored green.)
>
> Am I correct in seeing this as a bug? If so, any tips on what parts of diff.c to look at when starting a patch?
>
> Thanks,
>
> Simeon
>