Horton

Re: pure parsers and reentrant scanners

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Eisentraut <peter@eisentraut.org>
Cc: pgbuildfarm@rjuju.net, Andreas Karlsson <andreas@proxel.se>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2024-12-20T15:23:33Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Return yyparse() result not via global variable

  2. Remove flex version checks

  3. Drop warning-free support for Flex 2.5.35

  4. plpgsql: pure parser and reentrant scanner

  5. flex code modernization: Replace YY_EXTRA_TYPE define with flex option

  6. guc: reentrant scanner

  7. jsonpath scanner: reentrant scanner

  8. syncrep parser: pure parser and reentrant scanner

  9. replication parser: pure parser and reentrant scanner

  10. bootstrap: pure parser and reentrant scanner

  11. Small whitespace improvement

  12. Prevent redeclaration of typedef yyscan_t

  13. seg: pure parser and reentrant scanner

  14. cube: pure parser and reentrant scanner

Peter Eisentraut <peter@eisentraut.org> writes:
> On 20.12.24 02:07, Tom Lane wrote:
>> I noticed that lapwing is bleating about
>> cubescan.c:1689:5: warning: no previous prototype for 'cube_yyget_column' [-Wmissing-prototypes]
>> cubescan.c:1765:6: warning: no previous prototype for 'cube_yyset_column' [-Wmissing-prototypes]
>> and likewise in segscan.c.  lapwing is using flex 2.5.35, so probably
>> this is the same bug worked around in parser/scan.l:

> Ok, we can fix that, but maybe this is also a good moment to think about 
> whether that is useful.  I could not reproduce the issue with flex 
> 2.5.39.  I could find no download of flex 2.5.35.  The github site only 
> offers back to 2.5.39, the sourceforce site back to 2.5.36.  lapwing 
> says it's Debian 7.0, which went out of support in 2016 and out of 
> super-duper-extended support in 2020.  It also doesn't have a supported 
> OpenSSL version anymore, and IIRC, it has a weird old compiler that 
> occasionally gives bogus warnings.  I think it's time to stop supporting 
> this.

OK, that's fair.  I do see lapwing called out a lot in the commit log,
though it's not clear how much of that is about 32-bitness and how
much about old tools.  It's surely still valuable to have i386
machines in the buildfarm, but I agree that supporting unobtainable
tool versions is a bit much.  Could we get that animal updated to
some newer OS version?

Presumably, we should also rip out the existing yyget_column and
yyset_column kluges in

src/backend/parser/scan.l: extern int      core_yyget_column(yyscan_t yyscanner);
src/bin/psql/psqlscanslash.l: extern int   slash_yyget_column(yyscan_t yyscanner);
src/bin/pgbench/exprscan.l: extern int     expr_yyget_column(yyscan_t yyscanner);
src/fe_utils/psqlscan.l: extern int        psql_yyget_column(yyscan_t yyscanner);

			regards, tom lane