fix: handle IPv6 bracket notation in address parsing

Added _parse_address() helper that strips brackets from IPv6
addresses like [::1]:9001. Previously rsplit(":", 1) left brackets
in the host, which could cause issues with asyncio.open_connection.

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

Author: antoineleclair

src/dqliteclient/cluster.py

@@ -2,7 +2,7 @@
 
 import asyncio
 
-from dqliteclient.connection import DqliteConnection
+from dqliteclient.connection import DqliteConnection, _parse_address
 from dqliteclient.exceptions import ClusterError, DqliteConnectionError, OperationalError
 from dqliteclient.node_store import MemoryNodeStore, NodeInfo, NodeStore
 from dqliteclient.protocol import DqliteProtocol
@@ -65,8 +65,7 @@ async def find_leader(self) -> str:
 
     async def _query_leader(self, address: str) -> str | None:
         """Query a node for the current leader."""
-        host, port_str = address.rsplit(":", 1)
-        port = int(port_str)
+        host, port = _parse_address(address)
 
         try:
             reader, writer = await asyncio.wait_for(

src/dqliteclient/connection.py

@@ -9,6 +9,18 @@
 from dqliteclient.protocol import DqliteProtocol
 
 
+def _parse_address(address: str) -> tuple[str, int]:
+    """Parse a host:port address string, handling IPv6 brackets."""
+    if address.startswith("["):
+        # Bracketed IPv6: [host]:port
+        bracket_end = address.index("]")
+        host = address[1:bracket_end]
+        port_str = address[bracket_end + 2:]  # Skip ']:
+    else:
+        host, port_str = address.rsplit(":", 1)
+    return host, int(port_str)
+
+
 class DqliteConnection:
     """High-level async connection to a dqlite database."""
 
@@ -48,8 +60,7 @@ async def connect(self) -> None:
         if self._protocol is not None:
             return
 
-        host, port_str = self._address.rsplit(":", 1)
-        port = int(port_str)
+        host, port = _parse_address(self._address)
 
         try:
             reader, writer = await asyncio.wait_for(

tests/test_connection.py

@@ -8,6 +8,28 @@
 from dqliteclient.exceptions import DqliteConnectionError
 
 
+class TestParseAddress:
+    def test_ipv4(self) -> None:
+        from dqliteclient.connection import _parse_address
+
+        assert _parse_address("localhost:9001") == ("localhost", 9001)
+
+    def test_ipv4_ip(self) -> None:
+        from dqliteclient.connection import _parse_address
+
+        assert _parse_address("192.168.1.1:9001") == ("192.168.1.1", 9001)
+
+    def test_ipv6_bracketed(self) -> None:
+        from dqliteclient.connection import _parse_address
+
+        assert _parse_address("[::1]:9001") == ("::1", 9001)
+
+    def test_ipv6_full_bracketed(self) -> None:
+        from dqliteclient.connection import _parse_address
+
+        assert _parse_address("[2001:db8::1]:9001") == ("2001:db8::1", 9001)
+
+
 class TestDqliteConnection:
     def test_init(self) -> None:
         conn = DqliteConnection("localhost:9001", database="test", timeout=5.0)