- Fixed bug where known boolean values used by

:func:`.engine_from_config` were not being parsed correctly;
these included ``pool_threadlocal`` and the psycopg2 argument
``use_native_unicode``. fixes #3435
- add legacy_schema_aliasing config parsing for mssql
- move use_native_unicode config arg to the psycopg2 dialect

4 files changed, 16 insertions, 9 deletions

diff --git a/lib/sqlalchemy/dialects/mssql/base.py b/lib/sqlalchemy/dialects/mssql/base.py
index d61ab1958..928953126 100644
--- a/lib/sqlalchemy/dialects/mssql/base.py
+++ b/lib/sqlalchemy/dialects/mssql/base.py
@@ -1494,6 +1494,10 @@ class MSDialect(default.DefaultDialect):
         sqltypes.Time: TIME,
     }
 
+    engine_config_types = default.DefaultDialect.engine_config_types.union([
+        ('legacy_schema_aliasing', util.asbool),
+    ])
+
     ischema_names = ischema_names
 
     supports_native_boolean = False
diff --git a/lib/sqlalchemy/dialects/postgresql/psycopg2.py b/lib/sqlalchemy/dialects/postgresql/psycopg2.py
index f66ba9693..f83bab2fa 100644
--- a/lib/sqlalchemy/dialects/postgresql/psycopg2.py
+++ b/lib/sqlalchemy/dialects/postgresql/psycopg2.py
@@ -505,6 +505,10 @@ class PGDialect_psycopg2(PGDialect):
     _has_native_json = False
     _has_native_jsonb = False
 
+    engine_config_types = PGDialect.engine_config_types.union([
+        ('use_native_unicode', util.asbool),
+    ])
+
     colspecs = util.update_copy(
         PGDialect.colspecs,
         {
diff --git a/lib/sqlalchemy/engine/__init__.py b/lib/sqlalchemy/engine/__init__.py
index 0678dd201..f1eacf6a6 100644
--- a/lib/sqlalchemy/engine/__init__.py
+++ b/lib/sqlalchemy/engine/__init__.py
@@ -394,9 +394,9 @@ def engine_from_config(configuration, prefix='sqlalchemy.', **kwargs):
     'prefix' argument indicates the prefix to be searched for.
 
     A select set of keyword arguments will be "coerced" to their
-    expected type based on string values.  In a future release, this
-    functionality will be expanded and include dialect-specific
-    arguments.
+    expected type based on string values.    The set of arguments
+    is extensible per-dialect using the ``engine_config_types`` accessor.
+
     """
 
     options = dict((key[len(prefix):], configuration[key])
diff --git a/lib/sqlalchemy/engine/default.py b/lib/sqlalchemy/engine/default.py
index 9330a602c..9a7b80bfd 100644
--- a/lib/sqlalchemy/engine/default.py
+++ b/lib/sqlalchemy/engine/default.py
@@ -61,14 +61,13 @@ class DefaultDialect(interfaces.Dialect):
 
     engine_config_types = util.immutabledict([
         ('convert_unicode', util.bool_or_str('force')),
-        ('pool_timeout', int),
+        ('pool_timeout', util.asint),
         ('echo', util.bool_or_str('debug')),
         ('echo_pool', util.bool_or_str('debug')),
-        ('pool_recycle', int),
-        ('pool_size', int),
-        ('max_overflow', int),
-        ('pool_threadlocal', bool),
-        ('use_native_unicode', bool),
+        ('pool_recycle', util.asint),
+        ('pool_size', util.asint),
+        ('max_overflow', util.asint),
+        ('pool_threadlocal', util.asbool),
     ])
 
     # if the NUMERIC type