Bug#58165: "my_empty_string" gets modified and causes LOAD DATA to fail and

other crashes

Some string manipulating SQL functions use a shared string object intended to
contain an immutable empty string. This object was used by the SQL function
SUBSTRING_INDEX() to return an empty string when one argument was of the wrong
datatype. If the string object was then modified by the sql function INSERT(),
undefined behavior ensued.

Fixed by instead modifying the string object representing the function's
result value whenever string manipulating SQL functions return an empty
string.

Relevant code has also been documented.

1 files changed, 16 insertions, 0 deletions

diff --git a/mysql-test/r/func_str.result b/mysql-test/r/func_str.result
index 0321b2d85ad..8f4038e1239 100644
--- a/mysql-test/r/func_str.result
+++ b/mysql-test/r/func_str.result
@@ -2612,4 +2612,20 @@ CONVERT(('' IN (REVERSE(CAST(('') AS DECIMAL)), '')), CHAR(3))
 1
 Warnings:
 Warning	1292	Truncated incorrect DECIMAL value: ''
+# 
+# Bug#58165: "my_empty_string" gets modified and causes LOAD DATA to fail
+# and other crashes
+#
+CREATE TABLE t1 ( a TEXT );
+SELECT 'aaaaaaaaaaaaaa' INTO OUTFILE 'bug58165.txt';
+SELECT insert( substring_index( 'a', 'a', 'b' ), 1, 0, 'x' );
+insert( substring_index( 'a', 'a', 'b' ), 1, 0, 'x' )
+x
+Warnings:
+Warning	1292	Truncated incorrect INTEGER value: 'b'
+LOAD DATA INFILE 'bug58165.txt' INTO TABLE t1;
+SELECT * FROM t1;
+a
+aaaaaaaaaaaaaa
+DROP TABLE t1;
 End of 5.1 tests