Re: [RFC] building postgres with meson

Hi,

On 2022-08-09 08:37:16 -0400, Andrew Dunstan wrote:
> On 2022-08-09 Tu 03:10, Andres Freund wrote:
> > Hi,
> >
> > I was looking at re-unifying gendef2.pl that the meson patchset had introduced
> > for temporary ease during hacking with gendef.pl. Testing that I noticed that
> > either I and my machine is very confused, or gendef.pl's check whether it can
> > skip work is bogus.
> >
> > I noticed that, despite having code to avoid rerunning when the input files
> > are older than the .def file, it always runs.
> >
> > # if the def file exists and is newer than all input object files, skip
> > # its creation
> > if (-f $deffile
> > && (-M $deffile > max(map { -M } <$ARGV[0]/*.obj>)))
> > {
> > print "Not re-generating $defname.DEF, file already exists.\n";
> > exit(0);
> > }
> >
> > My understanding of -M is that it returns the time delta between the file
> > modification and the start of the script. Which makes the use of max() bogus,
> > since it'll return the oldest time any input has been modified, not the
> > newest. And the condition needs to be inverted, because we want to skip the
> > work if $deffile is *newer*, right?
> >
> > Am I missing something here?
>
>
> No, you're right, this is bogus. Reversing the test and using min
> instead of max is the obvious fix.
>
>
> > I'm tempted to just remove the not-regenerating logic - gendef.pl shouldn't
> > run if there's nothing to do, and it'll e.g. not notice if there's an
> > additional input that wasn't there during the last invocation of gendef.pl.
> >
>
> Maybe, need to think about that more.

Any thoughts?

I'd like to commit 0003 in
https://postgr.es/m/20220811002012.ju3rrz47i2e5tdha%40awork3.anarazel.de
fairly soon.

I did fix the bogus "die" message I added during some debugging since posting
that...

Greetings,

Andres Freund