Re: Why do we have perl and sed versions of Gen_dummy_probes?

On 5/11/21 4:01 PM, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
>> On 2021-05-11 14:30:10 -0400, Andrew Dunstan wrote:
>>> I'm not aware of any other case where we generate an in-tree file from a
>>> vpath, which is why it feels strange.
>> Yea, it is a bit odd, agreed. We don't have many generated sources
>> inside the git repo (vs in the tarball). The most prominent one is
>> configure, obviously...
> I think this is overly cute.  As a counterexample, the rules to regenerate
> gram.c and similar files don't bend over backwards like that to force the
> output to be in the srcdir.
>
> I haven't dug in the gmake manual to be sure, but I think that in a VPATH
> build, $@ will refer to the file in the srcdir if the file exists there
> but is out-of-date.  So if you go with the straightforward use of $< and
> $@, I believe it will in fact work.  The only way to make it fail under
> VPATH would be to do
> 	rm path/to/srcdir/Gen_dummy_probes.pl; make Gen_dummy_probes.pl
> which I think is sufficiently unlikely to not be a problem.  In fact,
> one could argue that building Gen_dummy_probes.pl in the VPATH dir
> is exactly what the user is trying to make happen if she does this.
>
> In short: don't be cuter than the longstanding bison/flex rules are.
>
> 			

What will she do with it? gram.c generated in a vpath build is 100%
usable where it's generated. Also. it's not a file we keep in the git repo.

Not gonna fight, there's been way too much energy spent on this. I'll
just do what Alvaro suggested. But I won't be surprised if some future
commit is missing the perl update.


cheers


andrew




--
Andrew Dunstan
EDB: https://www.enterprisedb.com