Re: MinGW compiler warnings in ecpg tests

Hi,

On 2024-12-06 15:44:20 +1300, Thomas Munro wrote:
> On Fri, Dec 6, 2024 at 4:13 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > Thomas Munro <thomas(dot)munro(at)gmail(dot)com> writes:
> > > Yeah. This warning is visible on CI, and on fairywren since its MSYS2
> > > upgrade a couple of months ago. Old MinGW didn't like %lld (I think
> > > perhaps the printf from msvcrt.dll from 1996 didn't like it and MinGW
> > > knew that), but new MinGW doesn't like %I64d (that's interesting, but
> > > not relevant here because %lld is clearly the correct format string,
> > > and it works). We should just revert that change. Here's a patch.
> >
> > +1
>
> Thanks for looking. Pushed, and that fixed that on fairywren.
>
> > > Those were there before the upgrade. POSIX says that environ should
> > > not be declared by a header, but Windows apparently declares it, or at
> > > least its cousin _environ, in <stdlib.h> which we include in c.h. I
> > > have no idea why Visual Studio doesn't warn, or why the documentation
> > > only tells you about _environ and not environ, or where the macro (?)
> > > comes from that renames it, but it passes CI and is
> > > warning-free on both toolchains if you just hide the offending
> > > declarations.
> >
> > Isn't this likely to break things for every other Windows toolchain?
> > I think the concept might be OK, but we need a tighter #if condition.
>
> Cool, I'll do that for MinGW only then.

I was looking at merging [1], however the backbranches < 18 fail in
CompilerWarnings due to this error [2], after upgrading to trixie. Seems like
we ought to backpatch 7bc9a8bdd2d. Haven't checked yet whether 1319997d is
also required for a clean build.

Greetings,

Andres Freund

[1] https://postgr.es/m/CAN55FZ1_B1usTskAv%2BAYt1bA7abVd9YH6XrUUSbr-2Z0d5Wd8w%40mail.gmail.com
[2] https://cirrus-ci.com/task/6526575971139584