Beginning of line anchor doesn't seem to work in REGEXP_REPLACE

[bendavis78]

Here's a normal replacement, without any anchors (works fine):

mysql> SELECT REGEXP_REPLACE('ABCABC', 'A', '*');
+------------------------------------+
| REGEXP_REPLACE('ABCABC', 'A', '*') |
+------------------------------------+
| *BC*BC                             |
+------------------------------------+
1 row in set (0.00 sec)

If we add the beginning of line anchor, it fails to replace:

mysql> SELECT REGEXP_REPLACE('ABCABC', '^A', '*');
+-------------------------------------+
| REGEXP_REPLACE('ABCABC', '^A', '*') |
+-------------------------------------+
| ABCABC                              |
+-------------------------------------+
1 row in set (0.00 sec)

End of line anchor works fine:

mysql> SELECT REGEXP_REPLACE('ABCABC', 'C$', '*');
+-------------------------------------+
| REGEXP_REPLACE('ABCABC', 'C$', '*') |
+-------------------------------------+
| ABCAB*                              |
+-------------------------------------+
1 row in set (0.00 sec)