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6eaf7e5bea
When the number of allowed iterations is limited (either a "?" quantifier
or a bound expression), the last sub-match has to reach to the end of the
target string. The previous coding here first tried the shortest possible
match (one character, usually) and then gave up and back-tracked if that
didn't work, typically leading to failure to match overall, as shown in
bug #11478 from Christoph Berg. The minimum change to fix that would be to
not decrement k before "goto backtrack"; but that would be a pretty stupid
solution, because we'd laboriously try each possible sub-match length
before finally discovering that only ending at the end can work. Instead,
force the sub-match endpoint limit up to the end for even the first
shortest() call if we cannot have any more sub-matches after this one.
Bug introduced in my rewrite that added the iterdissect logic, commit
173e29aa5d. The shortest-first search code
was too closely modeled on the longest-first code, which hasn't got this
issue since it tries a match reaching to the end to start with anyway.
Back-patch to all affected branches.
52 lines
2.1 KiB
SQL
52 lines
2.1 KiB
SQL
--
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-- Regular expression tests
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--
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-- Don't want to have to double backslashes in regexes
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set standard_conforming_strings = on;
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-- Test simple quantified backrefs
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select 'bbbbb' ~ '^([bc])\1*$' as t;
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select 'ccc' ~ '^([bc])\1*$' as t;
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select 'xxx' ~ '^([bc])\1*$' as f;
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select 'bbc' ~ '^([bc])\1*$' as f;
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select 'b' ~ '^([bc])\1*$' as t;
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-- Test quantified backref within a larger expression
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select 'abc abc abc' ~ '^(\w+)( \1)+$' as t;
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select 'abc abd abc' ~ '^(\w+)( \1)+$' as f;
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select 'abc abc abd' ~ '^(\w+)( \1)+$' as f;
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select 'abc abc abc' ~ '^(.+)( \1)+$' as t;
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select 'abc abd abc' ~ '^(.+)( \1)+$' as f;
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select 'abc abc abd' ~ '^(.+)( \1)+$' as f;
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-- Test some cases that crashed in 9.2beta1 due to pmatch[] array overrun
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select substring('asd TO foo' from ' TO (([a-z0-9._]+|"([^"]+|"")+")+)');
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select substring('a' from '((a))+');
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select substring('a' from '((a)+)');
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-- Test conversion of regex patterns to indexable conditions
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explain (costs off) select * from pg_proc where proname ~ 'abc';
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explain (costs off) select * from pg_proc where proname ~ '^abc';
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explain (costs off) select * from pg_proc where proname ~ '^abc$';
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explain (costs off) select * from pg_proc where proname ~ '^abcd*e';
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explain (costs off) select * from pg_proc where proname ~ '^abc+d';
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explain (costs off) select * from pg_proc where proname ~ '^(abc)(def)';
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explain (costs off) select * from pg_proc where proname ~ '^(abc)$';
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explain (costs off) select * from pg_proc where proname ~ '^(abc)?d';
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-- Test for infinite loop in pullback() (CVE-2007-4772)
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select 'a' ~ '($|^)*';
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-- Test for infinite loop in fixempties() (Tcl bugs 3604074, 3606683)
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select 'a' ~ '((((((a)*)*)*)*)*)*';
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select 'a' ~ '((((((a+|)+|)+|)+|)+|)+|)';
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-- Test backref in combination with non-greedy quantifier
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-- https://core.tcl.tk/tcl/tktview/6585b21ca8fa6f3678d442b97241fdd43dba2ec0
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select 'Programmer' ~ '(\w).*?\1' as t;
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select regexp_matches('Programmer', '(\w)(.*?\1)', 'g');
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-- Test for proper matching of non-greedy iteration (bug #11478)
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select regexp_matches('foo/bar/baz',
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'^([^/]+?)(?:/([^/]+?))(?:/([^/]+?))?$', '');
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