fix for bug #12595 (ESCAPE must be exactly 1 character long)

ESCAPE has length of 1 if specified and sql_mode is NO_BACKSLASH_ESCAPES
or has length of 0 or 1 in every other situation.
(approved patch applied on a up-to-date tree re-commit) 


mysql-test/r/select.result:
  results of test for bug 12595
mysql-test/t/select.test:
  test for bug #12595 (ESCAPE must be exactly one character long)
sql/item_cmpfunc.cc:
  if ESCAPE was in the statement check whether its length is
  different than 1. In NO_BACKSLASH_ESCAPES mode only length of 1 is
  allowed, otherwise the length could be 0 or 1 character (code point
  in the sense of Unicode).
sql/item_cmpfunc.h:
  pass variable from the parsing stage - whether
  ESCAPE clause was found in the statement
sql/sql_help.cc:
  pass FALSE for escape_used_in_parsing because we
  want the default mode of no error checking - our internal code.
sql/sql_lex.cc:
  initialized variable used to transfer information during
  parsing up in the stack when reducing in the grammar
sql/sql_lex.h:
  new variable used for transfering information when
  reducing in the grammar.
sql/sql_yacc.yy:
  initialize Lex->escape_used and then use it when reducing.
  This is needed as fix for bug #12595 to distinguish between
  situation where ESCAPE was found and when not because internally
  we may pass a string an empty string and there is no other way
  to find out whether this is correct or not in case of 
  NO_BACKSLASH_ESCAPES mode, which allows only length of 1 if
  ESCAPE is part of the SQL statement.

1 files changed, 57 insertions, 0 deletions

diff --git a/mysql-test/r/select.result b/mysql-test/r/select.result
index abf607dd438..fb61095cf22 100644
--- a/mysql-test/r/select.result
+++ b/mysql-test/r/select.result
@@ -2965,6 +2965,63 @@ NULL
 SELECT IFNULL(NULL, NULL);
 IFNULL(NULL, NULL)
 NULL
+SET @OLD_SQL_MODE12595=@@SQL_MODE, @@SQL_MODE='';
+SHOW LOCAL VARIABLES LIKE 'SQL_MODE';
+Variable_name	Value
+sql_mode	
+CREATE TABLE BUG_12595(a varchar(100));
+INSERT INTO BUG_12595 VALUES ('hakan%'), ('hakank'), ("ha%an");
+SELECT * FROM BUG_12595 WHERE a LIKE 'hakan\%';
+a
+hakan%
+SELECT * FROM BUG_12595 WHERE a LIKE 'hakan*%' ESCAPE '*';
+a
+hakan%
+SELECT * FROM BUG_12595 WHERE a LIKE 'hakan**%' ESCAPE '**';
+ERROR HY000: Incorrect arguments to ESCAPE
+SELECT * FROM BUG_12595 WHERE a LIKE 'hakan%' ESCAPE '';
+a
+hakan%
+hakank
+SELECT * FROM BUG_12595 WHERE a LIKE 'hakan\%' ESCAPE '';
+a
+SELECT * FROM BUG_12595 WHERE a LIKE 'ha\%an' ESCAPE 0x5c;
+a
+ha%an
+SELECT * FROM BUG_12595 WHERE a LIKE 'ha%%an' ESCAPE '%';
+a
+ha%an
+SELECT * FROM BUG_12595 WHERE a LIKE 'ha\%an' ESCAPE '\\';
+a
+ha%an
+SELECT * FROM BUG_12595 WHERE a LIKE 'ha|%an' ESCAPE '|';
+a
+ha%an
+SET @@SQL_MODE='NO_BACKSLASH_ESCAPES';
+SHOW LOCAL VARIABLES LIKE 'SQL_MODE';
+Variable_name	Value
+sql_mode	NO_BACKSLASH_ESCAPES
+SELECT * FROM BUG_12595 WHERE a LIKE 'hakan\%';
+a
+SELECT * FROM BUG_12595 WHERE a LIKE 'hakan*%' ESCAPE '*';
+a
+hakan%
+SELECT * FROM BUG_12595 WHERE a LIKE 'hakan**%' ESCAPE '**';
+ERROR HY000: Incorrect arguments to ESCAPE
+SELECT * FROM BUG_12595 WHERE a LIKE 'hakan\%' ESCAPE '\\';
+ERROR HY000: Incorrect arguments to ESCAPE
+SELECT * FROM BUG_12595 WHERE a LIKE 'hakan%' ESCAPE '';
+ERROR HY000: Incorrect arguments to ESCAPE
+SELECT * FROM BUG_12595 WHERE a LIKE 'ha\%an' ESCAPE 0x5c;
+a
+ha%an
+SELECT * FROM BUG_12595 WHERE a LIKE 'ha|%an' ESCAPE '|';
+a
+ha%an
+SELECT * FROM BUG_12595 WHERE a LIKE 'hakan\n%' ESCAPE '\n';
+ERROR HY000: Incorrect arguments to ESCAPE
+SET @@SQL_MODE=@OLD_SQL_MODE12595;
+DROP TABLE BUG_12595;
 create table t1 (a char(1));
 create table t2 (a char(1));
 insert into t1 values ('a'),('b'),('c');