Re: [PATCH 3/3] tools/libxl: Rework invariants in libxl__domain_get_device_model_uid()

[Ian Jackson <iwj@xxxxxxxxxxxxxx>]

Andrew Cooper writes ("[PATCH 3/3] tools/libxl: Rework invariants in 
libxl__domain_get_device_model_uid()"):
> Various version of gcc, when compiling with -Og, complain:
> 
>   libxl_dm.c: In function 'libxl__domain_get_device_model_uid':
>   libxl_dm.c:256:12: error: 'kill_by_uid' may be used uninitialized in this 
> function [-Werror=maybe-uninitialized]
>     256 |         if (kill_by_uid)
>         |            ^

Thanks for working on this.  I have reviewed your changes and I see
where you are coming from.  The situation is not very nice, mostly
because we don't have proper sum types in C.

I'm sorry to say that with my release manager hat on I think it is too
late for this kind of reorganisation for 4.15, especially just to work
around an overzealous compiler warning.

I think we can fix the compiler warning simply by setting the
`kill_by_uid` variable on more of the exit paths.  This approach was
already taken in this code for one of the paths.

I would prefer that approach at this stage of the release.

Sorry,
Ian.