Re: [PATCH 1/2] fast-import: Fix an gcc -Wuninitialized warning

[Jeff King <peff@peff.net>]

On Thu, Mar 28, 2013 at 06:20:29PM +0000, Ramsay Jones wrote:

> Jeff King wrote:
> > On Tue, Mar 26, 2013 at 07:09:44PM +0000, Ramsay Jones wrote:
> > 
> >> Commit cbfd5e1c ("drop some obsolete "x = x" compiler warning hacks",
> >> 21-03-2013) removed a gcc hack that suppressed an "might be used
> >> uninitialized" warning issued by older versions of gcc.
> >>
> >> However, commit 3aa99df8 ('fast-import: clarify "inline" logic in
> >> file_change_m', 21-03-2013) addresses an (almost) identical issue
> >> (with very similar code), but includes additional code in it's
> >> resolution. The solution used by this commit, unlike that used by
> >> commit cbfd5e1c, also suppresses the -Wuninitialized warning on
> >> older versions of gcc.
> >>
> >> In order to suppress the warning (against the 'oe' symbol) in the
> >> note_change_n() function, we adopt the same solution used by commit
> >> 3aa99df8.
> > 
> > Yeah, they are essentially the same piece of code, so I don't mind this
> > change.  It is odd to me that gcc gets it right in one case but not the
> > other, but I think we are deep into the vagaries of the compiler's code
> > flow analysis here, and we cannot make too many assumptions.
> > 
> > Were you actually triggering this warning, and if so, on what version of
> > gcc? 
> 
> yes, with:
>     gcc v3.4.4 (cygwin)
>     gcc v4.1.2 (Linux)
>     msvc v15.00.30729.01 (VC/C++ 2008 express edition)
> no, with:
>     gcc v4.4.0 (msysgit)
>     clang 3.2 (Linux)
>     tcc v0.9.26 (Linux)
> [lcc can't compile git; I forget why exactly.]

Thanks. I do not mind this fix, as it matches the similar code, and it
is fairly straightforward. But I am also happy to let people running gcc
v3.4.4 and other ancient compilers deal with not turning on -Werror. ;)

-Peff