This patch fixes the problem by adding a new rule booleat_test.
This makes the grammar clearer and less conflicting.
Additionally, fixing %prec in this grammar branch:
- | boolean_test IS NULL_SYM %prec PREC_BELOW_NOT
+ | boolean_test IS NULL_SYM %prec IS
to have consistently "%prec IS" in all grammar branches starting
with "boolean_test IS ...".
It's not clear why these three rules needed different %prec before the fix:
- boolean_test IS TRUE
- boolean_test IS UNKNOWN
- boolean_test IS NULL
the parser couldn't parse `1=2 not between 3 and 5`
after `2` it expected only NOT2_SYM, but not NOT_SYM
(visible from the sql_yacc.output file), which resulted in
Syntax error ... near 'not between 3 and 4'
The parser was confused by a rather low NOT_SYM precedence and
%prec BETWEEN_SYM didn't resolve this confusion.
As a fix, let's remove any %precedence from NOT_SYM and
specify %prec explicitly in the only place where it matters for NOT_SYM.
In other places, such as for NOT BETWEEN, NOT_SYM won't have a
precedence, so bison won't be confused about it.
Tests with checking metadata or that cannot be run with
the view-protocol are excluded from --view-protocol.
For tests that do not allow the use of an additional connection,
the util connection is disabled with "--disable_service_connection".
Also cases with bugs for --view-protocol are disabled.
On parsing statements for which a starting backtick (`) delimiter doesn't have
a corresponding ending backtick, a current pointer to a position inside a
pre-processed buffer could go beyond the end of the buffer.
This bug report caused by the commit d496765903
"MDEV-22022 Various mangled SQL statements will crash 10.3 to 10.5 debug builds".
In order to fix the issue both pointers m_ptr and m_cpp_ptr must be
rolled back to previous position in raw input and pre-processed input streams
correspondingly in case end of query reached during parsing.
Lex_input_stream::scan_ident_delimited() could go beyond the end
of the input when a starting backtick (`) delimiter did not have a
corresponding ending backtick.
Fix: catch the case when yyGet() returns 0, which means
either eof-of-query or straight 0x00 byte inside backticks,
and make the parser fail on syntax error, displaying the left
backtick as the syntax error place.
In case of filename in a script like this:
SET CHARACTER_SET_CLIENT=17; -- 17 is 'filename'
SELECT doc.`Children`.0 FROM t1;
the ending backtick was not recognized as such because my_charlen() returns 0 for
a straight backtick (backticks must normally be encoded as @0060 in filename).
The same fix works for 'filename': the execution skips the backtick
and reaches the end of the query, then yyGet() returns 0.
This fix is OK for now. But eventually 'filename' should either be disallowed
as a parser character set, or fixed to handle encoded punctuation properly.
Shift-Reduce conflicts prevented parsing some queries with subqueries that
used set operations when the subqueries occurred in expressions or in IN
predicands.
The grammar rules for query expression were transformed in order to avoid
these conflicts. New grammar rules employ an idea taken from MySQL 8.0.
