Details
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Task
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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None
Description
The rule remember_tok_start in the bison grammar may cause shift/reduce conflicts.
In order to fix MDEV-19956 easier, lets get rid of remember_tok_start gradually.
As the first step let's change the token type for the following single-character operators from <NONE> to <kwd>.
%type <kwd>
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'-' '+' '*' '/' '%' '(' ')' |
',' '!' '{' '}' '&' '|' |
and replace remember_tok_start to token positions in with_list_element (to prove the conceipt), as follows:
@@ -15262,16 +15262,16 @@ with_list_element:
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MYSQL_YYABORT;
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Lex->with_column_list.empty();
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}
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- AS '(' remember_tok_start query_expression remember_tok_end ')' |
+ AS '(' query_expression ')' |
{
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LEX *lex= thd->lex;
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const char *query_start= lex->sphead ? lex->sphead->m_tmp_query |
: thd->query();
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- char *spec_start= $6 + 1; |
- With_element *elem= new With_element($1, *$2, $7); |
+ const char *spec_start= $5.pos() + 1; |
+ With_element *elem= new With_element($1, *$2, $6); |
if (elem == NULL || Lex->curr_with_clause->add_with_element(elem)) |
MYSQL_YYABORT;
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- if (elem->set_unparsed_spec(thd, spec_start, $8, |
+ if (elem->set_unparsed_spec(thd, spec_start, $7.pos(), |
spec_start - query_start))
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MYSQL_YYABORT;
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}
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Lex_input_stream::lex_one_token() will be changed to assign positions to the mentioned tokens, like this:
--- a/sql/sql_lex.cc
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+++ b/sql/sql_lex.cc
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@@ -1510,6 +1510,7 @@ int Lex_input_stream::lex_one_token(YYSTYPE *yylval, THD *thd) |
case MY_LEX_SKIP: // This should not happen |
if (c != ')') |
next_state= MY_LEX_START; // Allow signed numbers |
+ yylval->kwd.set_keyword(m_tok_start, 1);
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return((int) c); |
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case MY_LEX_MINUS_OR_COMMENT: |
Note, this change will not immediately resolve any conflicts.
Conflicts should be resolved in a separate patch by effectively replacing remember_tok_start to token positions in these grammar rules:
parenthesized_expr:
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remember_tok_start
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query_expression
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{
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if (!($$= Lex->create_item_query_expression(thd, $1, $2))) |
MYSQL_YYABORT;
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}
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subselect:
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remember_tok_start
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query_expression
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{
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if (!($$= Lex->parsed_subselect($2, $1))) |
YYABORT;
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}
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;
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Attachments
Issue Links
- blocks
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MDEV-19956 Queries with subqueries containing UNION are not parsed
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- Closed
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