fix(client): preserve original exception context with from clause

ClientError was wrapping caught exceptions without chaining them,
discarding the original traceback. Added `from e` to both raise
sites so the root cause is visible when debugging.

Author: fguillot

kanboard.py

@@ -166,7 +166,7 @@ def _parse_response(response: bytes) -> Any:
 
             return body.get("result")
         except ValueError as e:
-            raise ClientError(f"Failed to parse JSON response: {e}")
+            raise ClientError(f"Failed to parse JSON response: {e}") from e
 
     def _do_request(self, headers: Dict[str, str], body: Dict[str, Any]) -> Any:
         try:
@@ -182,7 +182,7 @@ def _do_request(self, headers: Dict[str, str], body: Dict[str, Any]) -> Any:
 
             response = http.urlopen(request, context=ssl_context, timeout=self._timeout).read()
         except Exception as e:
-            raise ClientError(str(e))
+            raise ClientError(str(e)) from e
         return self._parse_response(response)
 
     def execute(self, method: str, **kwargs: Any) -> Any:

tests/test_kanboard.py

@@ -52,9 +52,11 @@ def test_custom_auth_header(self):
         assert kwargs["headers"]["X-Auth-Header"] == "dXNlcm5hbWU6cGFzc3dvcmQ="
 
     def test_http_error(self):
-        self.urlopen.side_effect = Exception()
-        with self.assertRaises(kanboard.ClientError):
+        original = Exception("connection refused")
+        self.urlopen.side_effect = original
+        with self.assertRaises(kanboard.ClientError) as cm:
             self.client.remote_procedure()
+        self.assertIs(cm.exception.__cause__, original)
 
     def test_empty_response_raises_client_error(self):
         self.urlopen.return_value.read.return_value = b""
@@ -68,6 +70,7 @@ def test_json_parsing_failure(self):
         with self.assertRaises(kanboard.ClientError) as cm:
             self.client.remote_procedure()
         self.assertIn("Failed to parse JSON response", str(cm.exception))
+        self.assertIsInstance(cm.exception.__cause__, ValueError)
 
     def test_application_error(self):
         body = b'{"jsonrpc": "2.0", "error": {"code": -32603, "message": "Internal error"}, "id": 123}'