Horton

Re: shadow variables - pg15 edition

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: David Rowley <dgrowleyml@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Andres Freund <andres@anarazel.de>, Justin Pryzby <pryzby@telsasoft.com>, pgsql-hackers@postgresql.org, Tomas Vondra <tomas.vondra@postgresql.org>, Peter Smith <smithpb2250@gmail.com>
Date: 2022-10-12T01:39:49Z
Lists: pgsql-hackers

Attachments

On Tue, Oct 11, 2022 at 01:16:50PM +1300, David Rowley wrote:
> Aside from this issue, if anything I'd be keen to go a little further
> with this and upgrade to -Wshadow=local. The reason being is that I
> noticed that the const qualifier is not classed as "compatible" with
> the equivalently named and typed variable without the const qualifier.
> ISTM that there's close to as much opportunity to mix up two variables
> with the same name that are const and non-const as there are two
> variables with the same const qualifier. However, I'll be waiting for
> the dust to settle on the current flags before thinking any more about
> that.

-Wshadow=compatible-local causes one extra warning in postgres.c with
-DWRITE_READ_PARSE_PLAN_TREES:
postgres.c: In function ‘pg_rewrite_query’:
postgres.c:818:37: warning: declaration of ‘query’ shadows a parameter [-Wshadow=compatible-local]
  818 |                         Query      *query = lfirst_node(Query, lc);
      |                                     ^~~~~
postgres.c:771:25: note: shadowed declaration is here
  771 | pg_rewrite_query(Query *query)
      |                  ~~~~~~~^~~~~

Something like the patch attached would deal with this one.
--
Michael

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