bug#55205: 28.1.50; completion--replace illegally mutates completion candidates

[Daniel Mendler <mail@daniel-mendler.de>]

On 5/4/22 09:48, Lars Ingebrigtsen wrote:
> Stefan Monnier <monnier@iro.umontreal.ca> writes:
> 
>>> But I still have no idea why we're stripping text properties in the
>>> first place, so could you please explain that?
>>
>> It depends where.  In `completion--replace` it's explained in the
>> comment:
>>
>>     ;; The properties on `newtext' include things like the
>>     ;; `completions-first-difference' face, which we don't want to
>>     ;; include upon insertion.
> 
> So it's really about stripping modifications that completion has already
> done to the strings?  Well, that seems like an easy enough problem to
> deal with -- just remove those, and leave the rest of the text
> properties alone.

I don't understand where the discussion is going. The bug has been fixed
by copying the string, ensuring that any original candidate string stays
unchanged. Just stripping the properties which were supposedly added by
completion is not a good solution since the original candidate string
could already come with exactly these properties.

Daniel