Datasette.close() closes databases, shuts down executor, unlinks temp file

Datasette.close() iterates over every attached Database (including the
internal database), calls Database.close() on each, then shuts down the
ThreadPoolExecutor. Exceptions raised by one Database don't prevent the
others from being closed; the first exception is re-raised afterwards.
Idempotent.

Refs #2692

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/test_internals_datasette.py

@@ -3,8 +3,10 @@ Tests for the datasette.app.Datasette class
 """
 
 import dataclasses
+import os
 from datasette import Context
 from datasette.app import Datasette, Database, ResourcesSQL
+from datasette.database import DatasetteClosedError
 from datasette.resources import DatabaseResource
 from itsdangerous import BadSignature
 import pytest
@@ -213,3 +215,60 @@ async def test_allowed_resources_sql(datasette):
     assert isinstance(result, ResourcesSQL)
     assert "all_rules AS" in result.sql
     assert result.params["action"] == "view-table"
+
+
+@pytest.mark.asyncio
+async def test_datasette_close_closes_all_databases_and_executor():
+    ds = Datasette(memory=True)
+    await ds.invoke_startup()
+    # Confirm internal DB has write machinery running
+    assert ds._internal_database._write_thread is not None
+    assert ds._internal_database._write_thread.is_alive()
+    temp_path = ds._internal_database.path
+    assert os.path.exists(temp_path)
+    executor = ds.executor
+    ds.close()
+    # Executor is shut down
+    assert executor._shutdown
+    # All attached Database instances are closed
+    for db in ds.databases.values():
+        assert db._closed
+    assert ds._internal_database._closed
+    # Temp internal DB file is unlinked
+    assert not os.path.exists(temp_path)
+
+
+@pytest.mark.asyncio
+async def test_datasette_close_is_idempotent():
+    ds = Datasette(memory=True)
+    await ds.invoke_startup()
+    ds.close()
+    # Second call should be a no-op
+    ds.close()
+
+
+@pytest.mark.asyncio
+async def test_datasette_close_raises_on_use():
+    ds = Datasette(memory=True)
+    await ds.invoke_startup()
+    ds.close()
+    with pytest.raises(DatasetteClosedError):
+        await ds.get_internal_database().execute("select 1")
+
+
+@pytest.mark.asyncio
+async def test_datasette_close_continues_past_db_error():
+    # If one Database raises during close(), the others still get closed.
+    ds = Datasette(memory=True)
+    await ds.invoke_startup()
+
+    class Boom(Database):
+        def close(self):
+            raise RuntimeError("boom")
+
+    bad = ds.add_database(Boom(ds, is_memory=True), name="bad")
+    good = ds.add_database(Database(ds, is_memory=True), name="good")
+    with pytest.raises(RuntimeError, match="boom"):
+        ds.close()
+    assert good._closed
+    assert ds._internal_database._closed