fixup! Remove mirror_*_download functions

Author: sechkova

tuf/client_rework/updater_rework.py

@@ -149,6 +149,7 @@ def download_target(self, target: Dict, destination_directory: str):
         """
 
         temp_obj = None
+        file_mirror_errors = {}
         file_mirrors = mirrors.get_list_of_mirrors(
             "target", target["filepath"], self._mirrors
         )
@@ -163,10 +164,20 @@ def download_target(self, target: Dict, destination_directory: str):
                 _check_hashes_obj(temp_obj, target["fileinfo"]["hashes"])
                 break
 
-            except Exception as exception:
+            except Exception as exception:  # pylint:  disable=broad-except
+                # Store the exceptions until all mirrors are iterated.
+                # If an exception is raised from one mirror but a valid
+                # file is found in the next one, the first exception is ignored.
+                file_mirror_errors[file_mirror] = exception
+
                 if temp_obj:
                     temp_obj.close()
-                raise exceptions.NoWorkingMirrorError({file_mirror: exception})
+                    temp_obj = None
+
+        # If all mirrors are iterated but a file object is not successfully
+        # downloaded and verifies, raise the collected errors
+        if not temp_obj:
+            raise exceptions.NoWorkingMirrorError(file_mirror_errors)
 
         filepath = os.path.join(destination_directory, target["filepath"])
         sslib_util.persist_temp_file(temp_obj, filepath)
@@ -314,6 +325,7 @@ def _root_mirrors_download(self, root_mirrors: Dict) -> "RootWrapper":
             finally:
                 if temp_obj:
                     temp_obj.close()
+                    temp_obj = None
 
         if not intermediate_root:
             # If all mirrors are tried but a valid root file is not found,
@@ -353,6 +365,7 @@ def _load_timestamp(self) -> None:
             finally:
                 if temp_obj:
                     temp_obj.close()
+                    temp_obj = None
 
         if not verified_timestamp:
             raise exceptions.NoWorkingMirrorError(file_mirror_errors)
@@ -406,6 +419,7 @@ def _load_snapshot(self) -> None:
             finally:
                 if temp_obj:
                     temp_obj.close()
+                    temp_obj = None
 
         if not verified_snapshot:
             raise exceptions.NoWorkingMirrorError(file_mirror_errors)
@@ -461,6 +475,7 @@ def _load_targets(self, targets_role: str, parent_role: str) -> None:
             finally:
                 if temp_obj:
                     temp_obj.close()
+                    temp_obj = None
 
         if not verified_targets:
             raise exceptions.NoWorkingMirrorError(file_mirror_errors)