better handler API error parsing.

Possibly we encountered an error while parsing the API error JSON, like
connection closes early etc and the received JSON is invalid.

Better handle such scenario and build a valid error Dict to keep the
exception stack flow running and raise this message to the application.

extract the returned text so if we any bit of valid information at least
we can pass that to the application.

This could be helpfull to if we add calls to the API made for web
browser that returns HTML error message, it will fail to decode the
recieved error and raise a proper error.

closes #1504

Signed-off-by: Alexandre Lavigne <[email protected]>
(cherry picked from commit db59084)

gspread/exceptions.py

@@ -9,6 +9,7 @@
 from typing import Any, Mapping
 
 from requests import Response
+from requests.exceptions import JSONDecodeError
 
 
 class UnSupportedExportFormat(Exception):
@@ -40,7 +41,19 @@ class APIError(GSpreadException):
     such as when we attempt to retrieve things that don't exist."""
 
     def __init__(self, response: Response):
-        error = dict(response.json()["error"])
+        try:
+            error = response.json()["error"]
+        except JSONDecodeError:
+            # in case we failed to parse the error from the API
+            # build an empty error object to notify the caller
+            # and keep the exception raise flow running
+
+            error = {
+                "code": -1,
+                "message": response.text,
+                "status": "invalid JSON",
+            }
+
         super().__init__(error)
         self.response: Response = response
         self.error: Mapping[str, Any] = error