Re: [PATCH] git-compat-util: avoid redefining system function names

[Bagas Sanjaya <bagasdotme@gmail.com>]

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On Sat, Dec 03, 2022 at 03:02:05PM +0700, Bagas Sanjaya wrote:
> On Fri, Dec 02, 2022 at 06:05:38AM -0500, Jeff King wrote:
> > -- >8 --
> > Subject: [PATCH] git-compat-util: undefine system names before redeclaring
> >  them
> > 
> > When we define a macro to point a system function (e.g., flockfile) to
> > our custom wrapper, we should make sure that the system did not already
> > define it as a macro. This is rarely a problem, but can cause
> > compilation failures if both of these are true:
> > 
> >   - we decide to define our own wrapper even though the system provides
> >     the function; we know this happens at least with uclibc, which may
> >     declare flockfile, etc, without _POSIX_THREAD_SAFE_FUNCTIONS
> > 
> >   - the system version is declared as a macro; we know this happens at
> >     least with uclibc's version of getc_unlocked()
> > 
> > So just handling getc_unlocked() would be sufficient to deal with the
> > real-world case we've seen. But since it's easy to do, we may as well be
> > defensive about the other macro wrappers added in the previous patch.
> > 
> > Signed-off-by: Jeff King <peff@peff.net>
> > ---
> > There may be other similar cases lurking throughout the code base, but I
> > don't think it's worth anybody's time to go looking for them. If one of
> > them triggers on a real platform, we can deal with it then.
> > 
> >  git-compat-util.h | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/git-compat-util.h b/git-compat-util.h
> > index 83ec7b7941..76e4b11131 100644
> > --- a/git-compat-util.h
> > +++ b/git-compat-util.h
> > @@ -346,6 +346,7 @@ static inline int git_setitimer(int which UNUSED,
> >  				struct itimerval *newvalue UNUSED) {
> >  	return 0; /* pretend success */
> >  }
> > +#undef setitimer
> >  #define setitimer(which,value,ovalue) git_setitimer(which,value,ovalue)
> >  #endif
> >  
> > @@ -1480,6 +1481,9 @@ static inline void git_funlockfile(FILE *fh UNUSED)
> >  {
> >  	; /* nothing */
> >  }
> > +#undef flockfile
> > +#undef funlockfile
> > +#undef getc_unlocked
> >  #define flockfile(fh) git_flockfile(fh)
> >  #define funlockfile(fh) git_funlockfile(fh)
> >  #define getc_unlocked(fh) getc(fh)
> 
> The warnings gone away, thanks!
> 
> For this patch and the previous one [1],
> 
> Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
> 
> [1]: https://lore.kernel.org/git/Y4fH4rhcSztHwKvK@coredump.intra.peff.net/
> 

PING?

Is your patch ready for v2.39?

-- 
An old man doll... just what I always wanted! - Clara

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