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Tom Lane a7b61d4f5a Fix infinite-loop risk in fixempties() stage of regex compilation.
The previous coding of this function could get into situations where it
would never terminate, because successive passes would re-add EMPTY arcs
that had been removed by the previous pass.  Rewrite the function
completely using a new algorithm that is guaranteed to terminate, and
also seems to be usually faster than the old one.  Per Tcl bugs 3604074
and 3606683.

Tom Lane and Don Porter
2013-03-07 11:51:03 -05:00

44 lines
1.7 KiB
SQL

--
-- Regular expression tests
--
-- Don't want to have to double backslashes in regexes
set standard_conforming_strings = on;
-- Test simple quantified backrefs
select 'bbbbb' ~ '^([bc])\1*$' as t;
select 'ccc' ~ '^([bc])\1*$' as t;
select 'xxx' ~ '^([bc])\1*$' as f;
select 'bbc' ~ '^([bc])\1*$' as f;
select 'b' ~ '^([bc])\1*$' as t;
-- Test quantified backref within a larger expression
select 'abc abc abc' ~ '^(\w+)( \1)+$' as t;
select 'abc abd abc' ~ '^(\w+)( \1)+$' as f;
select 'abc abc abd' ~ '^(\w+)( \1)+$' as f;
select 'abc abc abc' ~ '^(.+)( \1)+$' as t;
select 'abc abd abc' ~ '^(.+)( \1)+$' as f;
select 'abc abc abd' ~ '^(.+)( \1)+$' as f;
-- Test some cases that crashed in 9.2beta1 due to pmatch[] array overrun
select substring('asd TO foo' from ' TO (([a-z0-9._]+|"([^"]+|"")+")+)');
select substring('a' from '((a))+');
select substring('a' from '((a)+)');
-- Test conversion of regex patterns to indexable conditions
explain (costs off) select * from pg_proc where proname ~ 'abc';
explain (costs off) select * from pg_proc where proname ~ '^abc';
explain (costs off) select * from pg_proc where proname ~ '^abc$';
explain (costs off) select * from pg_proc where proname ~ '^abcd*e';
explain (costs off) select * from pg_proc where proname ~ '^abc+d';
explain (costs off) select * from pg_proc where proname ~ '^(abc)(def)';
explain (costs off) select * from pg_proc where proname ~ '^(abc)$';
explain (costs off) select * from pg_proc where proname ~ '^(abc)?d';
-- Test for infinite loop in pullback() (CVE-2007-4772)
select 'a' ~ '($|^)*';
-- Test for infinite loop in fixempties() (Tcl bugs 3604074, 3606683)
select 'a' ~ '((((((a)*)*)*)*)*)*';
select 'a' ~ '((((((a+|)+|)+|)+|)+|)+|)';