fix: implement to_diff_tuple to fix rendering of alembic check

Author: eliasmistler

.gitignore

@@ -117,6 +117,9 @@ venv.bak/
 .spyderproject
 .spyproject
 
+# PyCharm project settings
+.idea
+
 # Rope project settings
 .ropeproject
 

src/alembic_utils/reversible_op.py

@@ -1,4 +1,4 @@
-from typing import TYPE_CHECKING, Type
+from typing import TYPE_CHECKING, Any, Type
 
 from alembic.autogenerate import renderers
 from alembic.operations import MigrateOperation, Operations
@@ -52,6 +52,9 @@ class CreateOp(ReversibleOp):
     def reverse(self):
         return DropOp(self.target)
 
+    def to_diff_tuple(self) -> tuple[Any, ...]:
+        return "create_entity", self.target.identity, str(self.target.to_sql_statement_create())
+
 
 @Operations.register_operation("drop_entity", "invoke_for_target_optional_cascade")
 class DropOp(ReversibleOp):
@@ -62,17 +65,34 @@ def __init__(self, target: "ReplaceableEntity", cascade: bool = False) -> None:
     def reverse(self):
         return CreateOp(self.target)
 
+    def to_diff_tuple(self) -> tuple[Any, ...]:
+        return "drop_entity", self.target.identity
+
 
 @Operations.register_operation("replace_entity", "invoke_for_target")
 class ReplaceOp(ReversibleOp):
     def reverse(self):
         return RevertOp(self.target)
 
+    def to_diff_tuple(self) -> tuple[Any, ...]:
+        return (
+            "replace_or_revert_entity",
+            self.target.identity,
+            str(self.target.to_sql_statement_create_or_replace()),
+        )
+
 
 class RevertOp(ReversibleOp):
     # Revert is never in an upgrade, so no need to implement reverse
     pass
 
+    def to_diff_tuple(self) -> tuple[Any, ...]:
+        return (
+            "replace_or_revert_entity",
+            self.target.identity,
+            str(self.target.to_sql_statement_create_or_replace()),
+        )
+
 
 ###################
 # Implementations #

src/alembic_utils/testbase.py

@@ -19,6 +19,7 @@
     "downgrade": alem_command.downgrade,
     "revision": alem_command.revision,
     "current": alem_command.current,
+    "check": alem_command.check,
 }
 
 

src/test/test_create_function.py

@@ -1,6 +1,11 @@
+import pytest
+from alembic.util import AutogenerateDiffsDetected
 from sqlalchemy import text
 
 from alembic_utils.pg_function import PGFunction
+from alembic_utils.pg_view import PGView
+from alembic_utils.replaceable_entity import register_entities
+from alembic_utils.testbase import run_alembic_command
 
 to_upper = PGFunction(
     schema="public",
@@ -12,9 +17,20 @@
         """,
 )
 
+TEST_VIEW_before = PGView(
+    schema="public",
+    signature="testExample",
+    definition="select feature_name from information_schema.sql_features",
+)
+TEST_VIEW_after = PGView(
+    schema="public",
+    signature="testExample",
+    definition="select feature_name, is_supported from information_schema.sql_features",
+)
+
 
 def test_create_and_drop(engine) -> None:
-    """Test that the alembic current command does not erorr"""
+    """Test that the alembic current command does not error"""
     # Runs with no error
     up_sql = to_upper.to_sql_statement_create()
     down_sql = to_upper.to_sql_statement_drop()
@@ -26,3 +42,17 @@ def test_create_and_drop(engine) -> None:
         assert result[0] == "HELLO"
         connection.execute(down_sql)
         assert True
+
+
+def test_check_diff_create(engine) -> None:
+    register_entities([TEST_VIEW_before])
+
+    with pytest.raises(AutogenerateDiffsDetected) as e_info:
+        run_alembic_command(engine, "check", {})
+
+    exp = (
+        "New upgrade operations detected: "
+        "[('create_entity', 'PGView: public.testExample', "
+        '\'CREATE VIEW "public"."testExample" AS select feature_name from information_schema.sql_features;\')]'
+    )
+    assert e_info.value.args[0] == exp