Re: Corrupted multibyte characters in command substitutions

[Ángel]

On 2022-01-08 at 00:22 +0100, Frank Heckenbach wrote:
> Ángel wrote:
> 
> > I think that had you tested the devel branch instead of the last
> > release, you could have skipped a lot of testing (but how would you
> > have known? it's an easy thing to miss).
> > https://savannah.gnu.org/patch/?10035 seems to have gone the "easy
> > fix", which you discarded to get a more thorough one.
> 
> Well, the hard part was the analysis. After I found the problem,
> the fix then wasn't that hard either way.
> 
> > I was impressed as well by your careful analysis.
> > 
> > Chet, I think you should consider if Frank patch isn't better than
> > the
> > previous one.
> > I agree however that it should be published as an official patch.
> > 1/512th chance of corruption, and only on certain bash versions is
> > unlikely to be noticed easily. Which is doesn't mean this isn't
> > really
> > important.
> 
> 1/512 may be rare (and thus the more surprising) for many users. In
> my case, it was (luckily?) more common since my script processed a
> number of UTF-8 strings which increases the chance of hitting it.
> Indeed, by varying the environment it was roughly as likely to work
> correctly or crash at one of 3 points or so.

Yes, I think it can be considered lucky that you were able to reproduce
it with ease. bugs that only happen once in a blue moon are well, hard.


> > By the way, your reproducer is not working for me with an unpatched
> > 5.1.8:
> 
> Well, as I wrote in my original mail, it may depend on other factors
> of my environment, and it would take more work to identify them.
> Anyway, the point is moot now; my test works on my system and shows
> that the bug is present in 5.1.12 and fixed in 5.1.16.

When you mentioned the environment in the previous mail I thought in
the environment block (which you reset with env -i). As for the
environment in general, yes, apparently there are more things that
cause it to be even more random.


Best regards