Support `ARRAY` of `Enum`, `JSON` or `JSONB`

Added support for columns or type :class:`.ARRAY` of :class:`.Enum`,
:class:`.JSON` or :class:`_postgresql.JSONB` in PostgreSQL.
Previously a workaround was required in these use cases.
Raise an explicit :class:`.exc.CompileError` when adding a table with a
column of type :class:`.ARRAY` of :class:`.Enum` configured with
:paramref:`.Enum.native_enum` set to ``False`` when
:paramref:`.Enum.create_constraint` is not set to ``False``

Fixes: #5265
Fixes: #5266
Change-Id: I83a2d20a599232b7066d0839f3e55ff8b78cd8fc

1 files changed, 41 insertions, 12 deletions

diff --git a/lib/sqlalchemy/dialects/postgresql/array.py b/lib/sqlalchemy/dialects/postgresql/array.py
index a3537ba60..84fbd2e50 100644
--- a/lib/sqlalchemy/dialects/postgresql/array.py
+++ b/lib/sqlalchemy/dialects/postgresql/array.py
@@ -5,19 +5,14 @@
 # This module is part of SQLAlchemy and is released under
 # the MIT License: http://www.opensource.org/licenses/mit-license.php
 
-from .base import colspecs
-from .base import ischema_names
+import re
+
 from ... import types as sqltypes
+from ... import util
 from ...sql import expression
 from ...sql import operators
 
 
-try:
-    from uuid import UUID as _python_UUID  # noqa
-except ImportError:
-    _python_UUID = None
-
-
 def Any(other, arrexpr, operator=operators.eq):
     """A synonym for the :meth:`.ARRAY.Comparator.any` method.
 
@@ -318,6 +313,25 @@ class ARRAY(sqltypes.ARRAY):
                 for x in arr
             )
 
+    @util.memoized_property
+    def _require_cast(self):
+        return self._against_native_enum or isinstance(
+            self.item_type, sqltypes.JSON
+        )
+
+    @util.memoized_property
+    def _against_native_enum(self):
+        return (
+            isinstance(self.item_type, sqltypes.Enum)
+            and self.item_type.native_enum
+        )
+
+    def bind_expression(self, bindvalue):
+        if self._require_cast:
+            return expression.cast(bindvalue, self)
+        else:
+            return bindvalue
+
     def bind_processor(self, dialect):
         item_proc = self.item_type.dialect_impl(dialect).bind_processor(
             dialect
@@ -349,8 +363,23 @@ class ARRAY(sqltypes.ARRAY):
                     tuple if self.as_tuple else list,
                 )
 
-        return process
-
+        if self._against_native_enum:
+            super_rp = process
+
+            def handle_raw_string(value):
+                inner = re.match(r"^{(.*)}$", value).group(1)
+                return inner.split(",") if inner else []
+
+            def process(value):
+                if value is None:
+                    return value
+                # isinstance(value, util.string_types) is required to handle
+                # the # case where a TypeDecorator for and Array of Enum is
+                # used like was required in sa < 1.3.17
+                return super_rp(
+                    handle_raw_string(value)
+                    if isinstance(value, util.string_types)
+                    else value
+                )
 
-colspecs[sqltypes.ARRAY] = ARRAY
-ischema_names["_array"] = ARRAY
+        return process