Re: pgsql: Move tablespace path re-creation from the makefiles to pg_regres

On Thu, Mar 25, 2021 at 07:44:02AM +0900, Michael Paquier wrote:
> On Wed, Mar 24, 2021 at 10:50:50AM -0400, Robert Haas wrote:
> > On Wed, Mar 24, 2021 at 5:56 AM Christoph Berg <myon@debian.org> wrote:
> >> Maybe creating the tablespace directory from within the testsuite
> >> would suffice?
> >>
> >> CREATE TABLE foo (t text);
> >> COPY foo FROM PROGRAM 'mkdir @testtablespace@';
> >> CREATE TABLESPACE regress_tblspace LOCATION '@testtablespace@';
> > 
> > Would that work on Windows?

That would entail forbidding various shell metacharacters in @testtablespace@.
One could avoid imposing such a restriction by adding a mkdir() function to
regress.c and writing it like:

CREATE FUNCTION mkdir(text)
   RETURNS void AS '@libdir@/regress@DLSUFFIX@', 'regress_mkdir'
   LANGUAGE C STRICT\;
  REVOKE ALL ON FUNCTION mkdir FROM public;
SELECT mkdir('@testtablespace@');
CREATE TABLESPACE regress_tblspace LOCATION '@testtablespace@';

> I doubt that all the Windows environments would be able to get their
> hands on that.

> And I am not sure either that this would work when it
> comes to the CI case, again on Windows.

How might a CI provider break that?