Bug#50542 5.5.x doesn't check length of key prefixes:

          corruption and crash results
      
An index creation statement where the index key
is larger/wider than the column it references 
should throw an error.
      
A statement like:
  CREATE TABLE t1 (a CHAR(1), PRIMARY KEY (A(255)))
did not error, but a segmentation fault followed when
an insertion was attempted on the table
      
The partial key validiation clause has been 
restructured to (hopefully) better document which
uses of partial keys are valid.

1 files changed, 28 insertions, 0 deletions

diff --git a/mysql-test/t/alter_table.test b/mysql-test/t/alter_table.test
index 2bfe6dbaa62..54c662bccf2 100644
--- a/mysql-test/t/alter_table.test
+++ b/mysql-test/t/alter_table.test
@@ -1089,3 +1089,31 @@ ALTER TABLE t1
   ADD i INT UNSIGNED NOT NULL AUTO_INCREMENT,
   AUTO_INCREMENT = 1;
 DROP TABLE t1;
+
+
+#
+# Bug#50542 5.5.x doesn't check length of key prefixes: 
+#           corruption and crash results
+#
+# This case is related to Bug#31031 (above)
+# A statement where the index key is larger/wider than
+# the column type, should cause an error
+#
+--error ER_WRONG_SUB_KEY
+CREATE TABLE t1 (a CHAR(1), PRIMARY KEY (a(255)));
+
+# Test other variants of creating indices
+CREATE TABLE t1 (a CHAR(1));
+#  ALTER TABLE
+--error ER_WRONG_SUB_KEY
+ALTER TABLE t1 ADD PRIMARY KEY (a(20));
+--error ER_WRONG_SUB_KEY
+ALTER TABLE t1 ADD KEY (a(20));
+#  CREATE INDEX
+--error ER_WRONG_SUB_KEY
+CREATE UNIQUE INDEX i1 ON t1 (a(20));
+--error ER_WRONG_SUB_KEY
+CREATE INDEX i2 ON t1 (a(20));
+# cleanup
+DROP TABLE t1;
+