fix bug with missing array base column imports when altering a column (#1227)

Author: dantownsend

piccolo/apps/migrations/auto/serialisation.py

@@ -738,6 +738,8 @@ def deserialise_params(params: dict[str, Any]) -> dict[str, Any]:
         if isinstance(value, str) and not isinstance(value, Enum):
             if value != "self":
                 params[key] = deserialise_legacy_params(name=key, value=value)
+        elif isinstance(value, SerialisedColumnInstance):
+            params[key] = value.instance
         elif isinstance(value, SerialisedClassInstance):
             params[key] = value.instance
         elif isinstance(value, SerialisedUUID):

tests/apps/migrations/auto/integration/test_migrations.py

@@ -693,9 +693,13 @@ def test_array_column_varchar(self):
 
     def test_array_column_bigint(self):
         """
-        There was a bug with using an array of ``BigInt`` - see issue 500 on
-        GitHub. It's because ``BigInt`` requires access to the parent table to
+        There was a bug with using an array of ``BigInt``:
+
+        http://github.com/piccolo-orm/piccolo/issues/500/
+
+        It's because ``BigInt`` requires access to the parent table to
         determine what the column type is.
+
         """
         self._test_migrations(
             table_snapshots=[
@@ -706,6 +710,26 @@ def test_array_column_bigint(self):
             ]
         )
 
+    def test_array_base_column_change(self):
+        """
+        There was a bug when trying to change the base column of an array:
+
+        https://github.com/piccolo-orm/piccolo/issues/1076
+
+        It wasn't importing the base column, e.g. for ``Array(Text())`` it
+        wasn't importing ``Text``.
+
+        """
+        self._test_migrations(
+            table_snapshots=[
+                [self.table(column)]
+                for column in [
+                    Array(base_column=Varchar()),
+                    Array(base_column=Text()),
+                ]
+            ]
+        )
+
     ###########################################################################
 
     # We deliberately don't test setting JSON or JSONB columns as indexes, as