Fix schema generation

src/houseplant/houseplant.py

@@ -260,6 +260,9 @@ def update_schema(self):
         materialized_views = self.db.get_database_materialized_views()
         dictionaries = self.db.get_database_dictionaries()
 
+        # Track processed tables to ensure first migration takes precedence
+        processed_tables = set()
+
         # Group statements by type
         table_statements = []
         mv_statements = []
@@ -282,13 +285,18 @@ def update_schema(self):
             if not table_name:
                 continue
 
+            # Skip if we've already processed this table
+            if table_name in processed_tables:
+                continue
+
             # Check tables first
             for table in tables:
                 if table[0] == table_name:
                     create_stmt = self.db.client.execute(
                         f"SHOW CREATE TABLE {table_name}"
                     )[0][0]
                     table_statements.append(create_stmt)
+                    processed_tables.add(table_name)
 
             # Then materialized views
             for mv in materialized_views:
@@ -298,6 +306,7 @@ def update_schema(self):
                         0
                     ][0]
                     mv_statements.append(create_stmt)
+                    processed_tables.add(table_name)
 
             # Finally dictionaries
             for dict in dictionaries:
@@ -307,6 +316,7 @@ def update_schema(self):
                         f"SHOW CREATE DICTIONARY {dict_name}"
                     )[0][0]
                     dict_statements.append(create_stmt)
+                    processed_tables.add(table_name)
 
         # Write schema file
         with open("ch/schema.sql", "w") as f:

tests/test_houseplant.py

@@ -146,6 +146,65 @@ def test_migration_with_view(tmp_path):
     return migration_content
 
 
+@pytest.fixture
+def duplicate_migrations(tmp_path):
+    # Set up test environment
+    migrations_dir = tmp_path / "ch/migrations"
+    migrations_dir.mkdir(parents=True)
+
+    # Create two migrations that modify the same table
+    migration1 = migrations_dir / "20240101000000_first_migration.yml"
+    migration2 = migrations_dir / "20240102000000_second_migration.yml"
+
+    migration1_content = """version: "{version}"
+name: {name}
+table: events
+
+development: &development
+  up: |
+    CREATE TABLE events (
+        id UInt32,
+        name String
+    ) ENGINE = MergeTree()
+    ORDER BY id
+  down: |
+    DROP TABLE events
+
+test:
+  <<: *development
+
+production:
+  <<: *development
+"""
+
+    migration2_content = """version: "{version}"
+name: {name}
+table: events
+
+development: &development
+  up: |
+    ALTER TABLE events ADD COLUMN description String
+  down: |
+    ALTER TABLE events DROP COLUMN description
+
+test:
+  <<: *development
+
+production:
+  <<: *development
+"""
+
+    migration1.write_text(
+        migration1_content.format(version="20240101000000", name="first_migration")
+    )
+    migration2.write_text(
+        migration2_content.format(version="20240102000000", name="second_migration")
+    )
+
+    os.chdir(tmp_path)
+    return ("20240101000000", "20240102000000")
+
+
 def test_migrate_up_development(houseplant, test_migration, mocker):
     # Mock environment and database calls
     houseplant.env = "development"
@@ -297,6 +356,48 @@ def test_migrate_up_with_production_view(houseplant, test_migration_with_view, m
     mock_get_applied.assert_called_once()
 
 
+def test_update_schema_no_duplicates(houseplant, duplicate_migrations, mocker):
+    versions = duplicate_migrations
+
+    # Mock database calls
+    mocker.patch.object(
+        houseplant.db,
+        "get_applied_migrations",
+        return_value=[(versions[0],), (versions[1],)],
+    )
+    mocker.patch.object(
+        houseplant.db, "get_database_tables", return_value=[("events",)]
+    )
+    mocker.patch.object(
+        houseplant.db, "get_database_materialized_views", return_value=[]
+    )
+    mocker.patch.object(houseplant.db, "get_database_dictionaries", return_value=[])
+
+    # Mock the SHOW CREATE TABLE call
+    mocker.patch.object(
+        houseplant.db.client,
+        "execute",
+        return_value=[
+            [
+                "CREATE TABLE events (id UInt32, name String) ENGINE = MergeTree() ORDER BY id"
+            ]
+        ],
+    )
+
+    # Update schema
+    houseplant.update_schema()
+
+    # Read the generated schema file
+    with open("ch/schema.sql", "r") as f:
+        schema_content = f.read()
+
+    # Verify the table appears only once in the schema
+    table_count = schema_content.count("CREATE TABLE events")
+    assert (
+        table_count == 1
+    ), f"Table 'events' appears {table_count} times in schema, expected 1"
+
+
 @pytest.mark.skip
 def test_migrate_down(houseplant, test_migration, mocker):
     # Mock database calls