bug#30525: Unexpected matches for input data from a patch file

[SF Markus Elfring]

> and this is the correct answer.

This view is appropriate for the core functionality.


>> * Does the tool “grep” output any extra colour information also for
>>    matched tab characters?
> 
> Not with that test case, no.

I am still unsure.


> There is no color information at all.

I suggest to take another look there.


> grep's --color option was not used.

The matched characters are marked in red (for other search patterns)
on my test system even if this command parameter is not passed explicitly.
It seems that it belongs to my default configuration for this program.

Will the visual representation change anywhere (because of escape sequences)
if you add it?


> As near as I can make out, the basic problem is
> that you didn't understand how grep is supposed to work,
> and reported its behavior as a bug.

My application knowledge was improvable.


> However, as far as I can see from the above example,
> grep is working as specified.

I got doubts from auxiliary functionality of match colouring.
There are further challenges to consider for special characters.

Would it make sense to replace them by printable variants?
https://en.wikipedia.org/wiki/C0_and_C1_control_codes
https://en.wikipedia.org/wiki/Unicode_control_characters#Control_pictures

Regards,
Markus