fix: set pool _initialized flag after loop, not before

If _create_connection() failed during initialize(), the flag was
already True, making initialize() permanently a no-op. The pool
was stuck empty with no recovery path. Now the flag is set only
after all connections are successfully created.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: antoineleclair

src/dqliteclient/pool.py

@@ -50,10 +50,10 @@ async def initialize(self) -> None:
         """Initialize the pool with minimum connections."""
         if self._initialized:
             return
-        self._initialized = True
         for _ in range(self._min_size):
             conn = await self._create_connection()
             await self._pool.put(conn)
+        self._initialized = True
 
     async def _create_connection(self) -> DqliteConnection:
         """Create a new connection to the leader."""

tests/test_pool.py

@@ -56,6 +56,36 @@ async def mock_connect(**kwargs):
 
         await pool.close()
 
+    async def test_initialize_retryable_after_failure(self) -> None:
+        """If initialize() fails, it should be retryable (not permanently stuck)."""
+        pool = ConnectionPool(["localhost:9001"], min_size=1, max_size=5)
+
+        call_count = 0
+
+        async def fail_then_succeed(**kwargs):
+            nonlocal call_count
+            call_count += 1
+            if call_count == 1:
+                raise OSError("Connection refused")
+            mock_conn = MagicMock()
+            mock_conn.is_connected = True
+            mock_conn.connect = AsyncMock()
+            mock_conn.close = AsyncMock()
+            return mock_conn
+
+        with patch.object(pool._cluster, "connect", side_effect=fail_then_succeed):
+            # First init fails
+            with pytest.raises(OSError):
+                await pool.initialize()
+
+            # Second init should work (not be a no-op)
+            await pool.initialize()
+
+        assert call_count == 2  # First failed, second succeeded
+        assert pool._size == 1
+
+        await pool.close()
+
     async def test_cancellation_does_not_leak_connection(self) -> None:
         """Cancelling a task that holds a connection should clean it up."""
         import asyncio