From d9388a51944e1c5bb389a33a2cd824a7e8672115 Mon Sep 17 00:00:00 2001
From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Sun, 22 Nov 2009 22:11:41 +0000
Subject: [PATCH] - VARCHAR/NVARCHAR will not render without a length, raises
 an error before passing to MySQL.   Doesn't impact CAST since VARCHAR is not
 allowed in MySQL CAST anyway, the dialect renders CHAR/NCHAR in those cases.
 [ticket:1252]

---
 CHANGES                               |  5 +++++
 lib/sqlalchemy/dialects/mysql/base.py | 19 ++++++++++++++-----
 test/dialect/test_mysql.py            | 17 +++++++++++++++--
 test/sql/test_types.py                |  6 +++---
 4 files changed, 37 insertions(+), 10 deletions(-)

diff --git a/CHANGES b/CHANGES
index 989e6145d1..0f19a1f0e4 100644
--- a/CHANGES
+++ b/CHANGES
@@ -513,6 +513,11 @@ CHANGES
     - New dialects: oursql, a new native dialect, 
       MySQL Connector/Python, a native Python port of MySQLdb,
       and of course zxjdbc on Jython.
+    
+    - VARCHAR/NVARCHAR will not render without a length, raises
+      an error before passing to MySQL.   Doesn't impact 
+      CAST since VARCHAR is not allowed in MySQL CAST anyway,
+      the dialect renders CHAR/NCHAR in those cases.
       
     - all the _detect_XXX() functions now run once underneath
       dialect.initialize()
diff --git a/lib/sqlalchemy/dialects/mysql/base.py b/lib/sqlalchemy/dialects/mysql/base.py
index a9acc2a013..d5ee4f5bb4 100644
--- a/lib/sqlalchemy/dialects/mysql/base.py
+++ b/lib/sqlalchemy/dialects/mysql/base.py
@@ -1561,19 +1561,28 @@ class MySQLTypeCompiler(compiler.GenericTypeCompiler):
         if type_.length:
             return self._extend_string(type_, {}, "VARCHAR(%d)" % type_.length)
         else:
-            return self._extend_string(type_, {}, "VARCHAR")
+            raise exc.InvalidRequestError("VARCHAR requires a length when rendered on MySQL")
     
     def visit_CHAR(self, type_):
-        return self._extend_string(type_, {'national':True}, "CHAR(%(length)s)" % {'length' : type_.length})
-
+        if type_.length:
+            return self._extend_string(type_, {}, "CHAR(%(length)s)" % {'length' : type_.length})
+        else:
+            return self._extend_string(type_, {}, "CHAR")
+            
     def visit_NVARCHAR(self, type_):
         # We'll actually generate the equiv. "NATIONAL VARCHAR" instead
         # of "NVARCHAR".
-        return self._extend_string(type_, {'national':True}, "VARCHAR(%(length)s)" % {'length': type_.length})
+        if type_.length:
+            return self._extend_string(type_, {'national':True}, "VARCHAR(%(length)s)" % {'length': type_.length})
+        else:
+            raise exc.InvalidRequestError("NVARCHAR requires a length when rendered on MySQL")
     
     def visit_NCHAR(self, type_):
         # We'll actually generate the equiv. "NATIONAL CHAR" instead of "NCHAR".
-        return self._extend_string(type_, {'national':True}, "CHAR(%(length)s)" % {'length': type_.length})
+        if type_.length:
+            return self._extend_string(type_, {'national':True}, "CHAR(%(length)s)" % {'length': type_.length})
+        else:
+            return self._extend_string(type_, {'national':True}, "CHAR")
     
     def visit_VARBINARY(self, type_):
         if type_.length:
diff --git a/test/dialect/test_mysql.py b/test/dialect/test_mysql.py
index b65ab6312d..325f518daa 100644
--- a/test/dialect/test_mysql.py
+++ b/test/dialect/test_mysql.py
@@ -7,7 +7,7 @@ import sets
 # end Py2K
 
 from sqlalchemy import *
-from sqlalchemy import sql, exc, schema
+from sqlalchemy import sql, exc, schema, types as sqltypes
 from sqlalchemy.dialects.mysql import base as mysql
 from sqlalchemy.test.testing import eq_
 from sqlalchemy.test import *
@@ -948,7 +948,20 @@ class SQLTest(TestBase, AssertsCompiledSQL):
             select([t]).offset(10),
             "SELECT t.col1, t.col2 FROM t  LIMIT 10, 18446744073709551615"
             )
-
+    
+    def test_varchar_raise(self):
+        for type_ in (
+            String,
+            VARCHAR,
+            String(),
+            VARCHAR(),
+            NVARCHAR(),
+            Unicode,
+            Unicode(),
+        ):
+            type_ = sqltypes.to_instance(type_)
+            assert_raises(exc.InvalidRequestError, type_.compile, dialect=mysql.dialect())
+            
     def test_update_limit(self):
         t = sql.table('t', sql.column('col1'), sql.column('col2'))
 
diff --git a/test/sql/test_types.py b/test/sql/test_types.py
index 332e02ef5f..04c193e01f 100644
--- a/test/sql/test_types.py
+++ b/test/sql/test_types.py
@@ -42,8 +42,8 @@ class AdaptTest(TestBase):
                 (DATE, "DATE"),
                 (TIME, "TIME"),
                 (CLOB, "CLOB"),
-                (VARCHAR, "VARCHAR"),
-                (NVARCHAR, ("NVARCHAR", "NATIONAL VARCHAR")),
+                (VARCHAR(10), "VARCHAR(10)"),
+                (NVARCHAR(10), ("NVARCHAR(10)", "NATIONAL VARCHAR(10)", "NVARCHAR2(10)")),
                 (CHAR, "CHAR"),
                 (NCHAR, ("NCHAR", "NATIONAL CHAR")),
                 (BLOB, "BLOB"),
@@ -52,7 +52,7 @@ class AdaptTest(TestBase):
                 if isinstance(expected, str):
                     expected = (expected, )
                 for exp in expected:
-                    compiled = type_().compile(dialect=dialect)
+                    compiled = types.to_instance(type_).compile(dialect=dialect)
                     if exp in compiled:
                         break
                 else:
-- 
2.47.3