Use in-memory database with shared cache

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 - #710, #561 Implement `except*` syntax (@lieryan)
 - #711 allow building documentation without having rope module installed (@kloczek)
+- #719 Allows the in-memory db to be shared across threads (@tkrabel)
 - #720 create one sqlite3.Connection per thread using a thread local (@tkrabel)
 
 # Release 1.10.0

rope/contrib/autoimport/sqlite.py

@@ -2,6 +2,8 @@
 
 import contextlib
 import json
+from hashlib import sha256
+import secrets
 import re
 import sqlite3
 import sys
@@ -153,14 +155,29 @@ def create_database_connection(
         memory : bool
             if true, don't persist to disk
         """
+
+        def calculate_project_hash(data: str) -> str:
+            return sha256(data.encode()).hexdigest()
+
         if not memory and project is None:
             raise Exception("if memory=False, project must be provided")
-        db_path: str
         if memory or project is None or project.ropefolder is None:
-            db_path = ":memory:"
+            # Allows the in-memory db to be shared across threads
+            # See https://www.sqlite.org/inmemorydb.html
+            project_hash: str
+            if project is None:
+                project_hash = secrets.token_hex()
+            elif project.ropefolder is None:
+                project_hash = calculate_project_hash(project.address)
+            else:
+                project_hash = calculate_project_hash(project.ropefolder.real_path)
+            return sqlite3.connect(
+                f"file:rope-{project_hash}:?mode=memory&cache=shared", uri=True
+            )
         else:
-            db_path = str(Path(project.ropefolder.real_path) / "autoimport.db")
-        return sqlite3.connect(db_path)
+            return sqlite3.connect(
+                str(Path(project.ropefolder.real_path) / "autoimport.db")
+            )
 
     @property
     def connection(self):

ropetest/conftest.py

@@ -13,6 +13,13 @@ def project():
     testutils.remove_project(project)
 
 
+@pytest.fixture
+def project2():
+    project = testutils.sample_project("another_project")
+    yield project
+    testutils.remove_project(project)
+
+
 @pytest.fixture
 def project_path(project):
     yield pathlib.Path(project.address)

ropetest/contrib/autoimport/autoimporttest.py

@@ -1,3 +1,4 @@
+import sqlite3
 from concurrent.futures import ThreadPoolExecutor
 from contextlib import closing, contextmanager
 from textwrap import dedent
@@ -27,6 +28,20 @@ def database_list(connection):
     return list(connection.execute("PRAGMA database_list"))
 
 
+def test_in_memory_database_share_cache(project, project2):
+    ai_1 = AutoImport(project, memory=True)
+    ai_2 = AutoImport(project, memory=True)
+
+    ai_3 = AutoImport(project2, memory=True)
+
+    with ai_1.connection:
+        ai_1.connection.execute("CREATE TABLE shared(data)")
+        ai_1.connection.execute("INSERT INTO shared VALUES(28)")
+    assert ai_2.connection.execute("SELECT data FROM shared").fetchone() == (28,)
+    with pytest.raises(sqlite3.OperationalError, match="no such table: shared"):
+        ai_3.connection.execute("SELECT data FROM shared").fetchone()
+
+
 def test_autoimport_connection_parameter_with_in_memory(
     project: Project,
     autoimport: AutoImport,