Horton

Re: shadow variables - pg15 edition

Alvaro Herrera <alvherre@alvh.no-ip.org>

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Andres Freund <andres@anarazel.de>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, David Rowley <dgrowleyml@gmail.com>, Justin Pryzby <pryzby@telsasoft.com>, pgsql-hackers@postgresql.org, Tomas Vondra <tomas.vondra@postgresql.org>, Peter Smith <smithpb2250@gmail.com>
Date: 2022-10-10T16:53:58Z
Lists: pgsql-hackers 
On 2022-Oct-10, Andres Freund wrote:

> On 2022-10-10 09:37:38 -0700, Andres Freund wrote:
> > On 2022-10-10 18:33:11 +0200, Alvaro Herrera wrote:
> > > On 2022-Oct-10, Andres Freund wrote:
> > > 
> > > > Given the age of affected perl instances I suspect there'll not be a lot of
> > > > developers affected, and the number of warnings is reasonably small too. It'd
> > > > likely hurt more developers to not see the warnings locally, given that such
> > > > shadowing often causes bugs.
> > > 
> > > Maybe we can install a filter-out in src/pl/plperl's Makefile for the
> > > time being.
> > 
> > We could, but is it really a useful thing for something fixed 6 years ago?

Well, for people purposefully installing using older installs of Perl
(not me, admittedly), it does seem useful, because you get the benefit
of checking shadow vars for the rest of the tree and still get no
warnings if everything is clean.

> As an out, a hypothetical dev could add -Wno-shadow=compatible-local to their
> CFLAGS.

But that disables it for the tree as a whole, which is not better.

We can remove the filter-out when we decide to move the Perl version
requirement up, say 4 years from now.

-- 
Álvaro Herrera               48°01'N 7°57'E  —  https://www.EnterpriseDB.com/
"El hombre nunca sabe de lo que es capaz hasta que lo intenta" (C. Dickens)

Commits

  1. Fix shadow variable in postgres.c

  2. Add -Wshadow=compatible-local to the standard compilation flags

  3. Fix final warnings produced by -Wshadow=compatible-local

  4. Fix final compiler warning produced by -Wshadow=compatible-local

  5. Add optional parameter to PG_TRY() macros

  6. Small refactor to get rid of -Wshadow=compatible-local warning

  7. More -Wshadow=compatible-local warning fixes

  8. Further -Wshadow=compatible-local warning fixes

  9. Further reduce warnings with -Wshadow=compatible-local

  10. Reduce warnings with -Wshadow=compatible-local builds

  11. Remove shadowed local variables that are new in v15