Handle bugzilla jsonrpc errors

Bugs not found are non-fatal and should be shown in the generated HTML,
but authentication errors should be fatal.

openqa_review/browser.py

@@ -30,6 +30,26 @@ class CacheNotFoundError(DownloadError):
     pass
 
 
+class BugzillaError(Exception):
+    """Bugzilla API returned error."""
+
+    def __init__(self, url, code, msg):
+        """Initialize."""
+        self.url = url
+        self.code = code
+        self.message = msg
+
+    def __str__(self):
+        """Stringify."""
+        return "Error retrieving '%s': code=%s msg='%s'" % (self.url, self.code, self.message)
+
+
+class BugNotFoundError(BugzillaError):
+    """A bugref points to a non-existing bug URL."""
+
+    pass
+
+
 def url_to_filename(url):
     """
     Convert URL to a valid, unambigous filename.
@@ -170,7 +190,14 @@ def json_rpc_get(self, url, method, params, cache=True):
         absolute_url = url if not url.startswith("/") else urljoin("http://dummy/", str(url))
         get_params = SortedDict({"method": method, "params": json.dumps([params])})
         get_url = requests.Request("GET", absolute_url, params=get_params).prepare().url
-        return self.get_json(get_url.replace("http://dummy", ""), cache)
+        response = self.get_json(get_url.replace("http://dummy", ""), cache)
+        if "error" in response and response["error"] is not None:
+            error = response["error"]
+            if error["code"] == 101:
+                raise BugNotFoundError(get_url, error["code"], error["message"])
+            else:
+                raise BugzillaError(get_url, error["code"], error["message"])
+        return response
 
     def json_rpc_post(self, url, method, params):
         """Execute JSON RPC POST request.

openqa_review/openqa_review.py

@@ -108,7 +108,7 @@
 
 sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), "..")))
 
-from openqa_review.browser import Browser, DownloadError, add_load_save_args  # isort:skip
+from openqa_review.browser import Browser, DownloadError, BugNotFoundError, add_load_save_args  # isort:skip
 
 
 # treat humanfriendly as optional dependency
@@ -701,7 +701,7 @@ def __init__(self, bugref, bugref_href, query_issue_status=False, progress_brows
                 )
                 self.msg = str(e)
                 self.error = True
-            except TypeError as e:
+            except BugNotFoundError as e:
                 log.error(
                     "Error retrieving details for bugref %s (%s): %s\n%s"
                     % (self.bugref, self.bugref_href, e, traceback.format_exc())