Re: [BUGS] BUG #14549: pl/pgsql parser

Hi

2017-02-17 8:58 GMT+01:00 <stefanov.sm@abv.bg>:

The following bug has been logged on the website:

Bug reference:      14549
Logged by:          Stefan Stefanov
Email address:      stefanov.sm@abv.bg
PostgreSQL version: 9.5.3
Operating system:   Red Hat, 64 bit
Description:

Hi all,
I found (the hard way) that in pl/pgsql SELECT INTO statement a syntax error
may remain unnoticed.
This simple example works as expected and produces '1, 2, 3' notice.

DO language plpgsql
$$
DECLARE
 vara integer;
 varb integer;
 varc integer;
BEGIN
 SELECT 1, 2, 3 INTO vara, varb, varc;
 RAISE NOTICE '% % %', vara, varb, varc;
END;
$$;

However if you omit a comma (or even replace the comma with AS) between varb
and varc in the INTO list then no syntax error is produced and the resulting
notice is '1 2 <NULL>'.

DO language plpgsql
$$
DECLARE
 vara integer;
 varb integer;
 varc integer;
BEGIN
 SELECT 1, 2, 3 INTO vara, varb AS varc;
 RAISE NOTICE '% % %', vara, varb, varc;
END;
$$;

A few more clearly erratic combinations of SELECT expressions and the INTO
list also 'work' and issue misleading results.
Same in functions. For me it produced a bug that was difficult to see and
track.

Best,
Stefan

It is not a bug - plpgsql is designed be tolerant to different columns and data types in left and right part of assignment.

You can use some tools for easy detecting these issues:

1. plpgsql_check https://github.com/okbob/plpgsql_check - it is available in community repository

2. prepared extra_checks https://commitfest.postgresql.org/13/962/

Regards

Pavel

 

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