clean up some imports (#1472)

* Remove unneeded import attempts from "tornado4". From what I can tell,
  this was only ever useful when using system packages on ubuntu 20.04.
  We don't support installation using system packages anymore (and
  ubuntu 20.04 is EOL).
* Remove misleading comment about monkey-patching the DB connection
  string in the test suite. We don't monkey-patch it anymore (instead we
  assume someone else fixed it and assert that it's correct).

Author: prandla

cms/io/web_service.py

@@ -28,10 +28,7 @@
     # Monkey-patch: Tornado 4.5.3 does not work on Python 3.11 by default
     collections.MutableMapping = collections.abc.MutableMapping
 
-try:
-    import tornado4.wsgi as tornado_wsgi
-except ImportError:
-    import tornado.wsgi as tornado_wsgi
+import tornado.wsgi
 from gevent.pywsgi import WSGIServer
 from werkzeug.contrib.fixers import ProxyFix
 from werkzeug.middleware.dispatcher import DispatcherMiddleware
@@ -71,7 +68,7 @@ def __init__(
         is_proxy_used = parameters.pop('is_proxy_used', None)
         num_proxies_used = parameters.pop('num_proxies_used', None)
 
-        self.wsgi_app = tornado_wsgi.WSGIApplication(handlers, **parameters)
+        self.wsgi_app = tornado.wsgi.WSGIApplication(handlers, **parameters)
         self.wsgi_app.service = self
 
         for entry in static_files:

cms/server/admin/handlers/base.py

@@ -46,10 +46,7 @@
     # Monkey-patch: Tornado 4.5.3 does not work on Python 3.11 by default
     collections.MutableMapping = collections.abc.MutableMapping
 
-try:
-    import tornado4.web as tornado_web
-except ImportError:
-    import tornado.web as tornado_web
+import tornado.web
 from sqlalchemy.exc import IntegrityError
 from sqlalchemy.orm import Query, subqueryload
 
@@ -81,7 +78,7 @@ def argument_reader(func: Callable[[str], typing.Any], empty: object = None):
     """
 
     def helper(
-        self: tornado_web.RequestHandler, dest: dict, name: str, empty: object = empty
+        self: tornado.web.RequestHandler, dest: dict, name: str, empty: object = empty
     ):
         """Read the argument called "name" and save it in "dest".
 
@@ -194,7 +191,7 @@ def decorator(
 
         """
         @wraps(func)
-        @tornado_web.authenticated
+        @tornado.web.authenticated
         def newfunc(self: _T, *args: _P.args, **kwargs: _P.kwargs):
             """Check if the permission is present before calling the function.
 
@@ -213,7 +210,7 @@ def newfunc(self: _T, *args: _P.args, **kwargs: _P.kwargs):
                     # the current user id.
                     return func(self, *args, **kwargs)
                 else:
-                    raise tornado_web.HTTPError(403, "Admin is not authorized")
+                    raise tornado.web.HTTPError(403, "Admin is not authorized")
 
         return newfunc
 
@@ -302,7 +299,7 @@ def safe_get_item(
             session = self.sql_session
         entity = cls.get_from_id(ident, session)
         if entity is None:
-            raise tornado_web.HTTPError(404)
+            raise tornado.web.HTTPError(404)
         return entity
 
     def prepare(self):
@@ -354,7 +351,7 @@ def render_params(self) -> dict:
 
     def write_error(self, status_code, **kwargs):
         if "exc_info" in kwargs and \
-                kwargs["exc_info"][0] != tornado_web.HTTPError:
+                kwargs["exc_info"][0] != tornado.web.HTTPError:
             exc_info = kwargs["exc_info"]
             logger.error(
                 "Uncaught exception (%r) while processing a request: %s",

cms/server/admin/handlers/contestannouncement.py

@@ -33,10 +33,7 @@
     # Monkey-patch: Tornado 4.5.3 does not work on Python 3.11 by default
     collections.MutableMapping = collections.abc.MutableMapping
 
-try:
-    import tornado4.web as tornado_web
-except ImportError:
-    import tornado.web as tornado_web
+import tornado.web
 
 from cms.db import Contest, Announcement
 from cmscommon.datetime import make_datetime
@@ -77,7 +74,7 @@ def delete(self, contest_id: str, ann_id: str):
 
         # Protect against URLs providing incompatible parameters.
         if self.contest is not ann.contest:
-            raise tornado_web.HTTPError(404)
+            raise tornado.web.HTTPError(404)
 
         self.sql_session.delete(ann)
         self.try_commit()

cms/server/admin/handlers/contestquestion.py

@@ -35,10 +35,7 @@
     # Monkey-patch: Tornado 4.5.3 does not work on Python 3.11 by default
     collections.MutableMapping = collections.abc.MutableMapping
 
-try:
-    import tornado4.web as tornado_web
-except ImportError:
-    import tornado.web as tornado_web
+import tornado.web
 
 from cms.db import Contest, Question, Participation
 from cmscommon.datetime import make_datetime
@@ -88,7 +85,7 @@ def post(self, contest_id, question_id):
 
         # Protect against URLs providing incompatible parameters.
         if self.contest is not question.participation.contest:
-            raise tornado_web.HTTPError(404)
+            raise tornado.web.HTTPError(404)
 
         self.process_question(question)
         self.redirect(ref)
@@ -148,7 +145,7 @@ class QuestionClaimHandler(QuestionActionHandler):
     def process_question(self, question):
         # Can claim/unclaim only a question not ignored or answered.
         if question.ignored or question.reply_timestamp is not None:
-            raise tornado_web.HTTPError(405)
+            raise tornado.web.HTTPError(405)
 
         should_claim = self.get_argument("claim", "no") == "yes"
 

cms/server/admin/handlers/contestuser.py

@@ -38,10 +38,7 @@
     # Monkey-patch: Tornado 4.5.3 does not work on Python 3.11 by default
     collections.MutableMapping = collections.abc.MutableMapping
 
-try:
-    import tornado4.web as tornado_web
-except ImportError:
-    import tornado.web as tornado_web
+import tornado.web
 
 from cms.db import Contest, Message, Participation, Submission, User, Team
 from cmscommon.datetime import make_datetime
@@ -113,7 +110,7 @@ def get(self, contest_id, user_id):
         )
         # Check that the participation is valid.
         if participation is None:
-            raise tornado_web.HTTPError(404)
+            raise tornado.web.HTTPError(404)
 
         submission_query = self.sql_session.query(Submission)\
             .filter(Submission.participation == participation)
@@ -193,7 +190,7 @@ def get(self, contest_id, user_id):
 
         # Check that the participation is valid.
         if participation is None:
-            raise tornado_web.HTTPError(404)
+            raise tornado.web.HTTPError(404)
 
         submission_query = self.sql_session.query(Submission)\
             .filter(Submission.participation == participation)
@@ -220,7 +217,7 @@ def post(self, contest_id, user_id):
 
         # Check that the participation is valid.
         if participation is None:
-            raise tornado_web.HTTPError(404)
+            raise tornado.web.HTTPError(404)
 
         try:
             attrs = participation.get_attrs()
@@ -281,7 +278,7 @@ def post(self, contest_id, user_id):
 
         # check that the participation is valid
         if participation is None:
-            raise tornado_web.HTTPError(404)
+            raise tornado.web.HTTPError(404)
 
         message = Message(make_datetime(),
                           self.get_argument("message_subject", ""),

cms/server/admin/handlers/dataset.py

@@ -39,10 +39,7 @@
     # Monkey-patch: Tornado 4.5.3 does not work on Python 3.11 by default
     collections.MutableMapping = collections.abc.MutableMapping
 
-try:
-    import tornado4.web as tornado_web
-except ImportError:
-    import tornado.web as tornado_web
+import tornado.web
 
 from cms.db import Dataset, Manager, Message, Participation, \
     Session, Submission, Task, Testcase
@@ -102,7 +99,7 @@ def get(self, dataset_id_to_copy):
                 self.safe_get_item(Dataset, dataset_id_to_copy)
             description = "Copy of %s" % original_dataset.description
         except ValueError:
-            raise tornado_web.HTTPError(404)
+            raise tornado.web.HTTPError(404)
 
         self.r_params = self.render_params()
         self.r_params["task"] = task
@@ -125,7 +122,7 @@ def post(self, dataset_id_to_copy):
             original_dataset = \
                 self.safe_get_item(Dataset, dataset_id_to_copy)
         except ValueError:
-            raise tornado_web.HTTPError(404)
+            raise tornado.web.HTTPError(404)
 
         try:
             attrs = dict()
@@ -406,7 +403,7 @@ def delete(self, dataset_id, manager_id):
 
         # Protect against URLs providing incompatible parameters.
         if manager.dataset is not dataset:
-            raise tornado_web.HTTPError(404)
+            raise tornado.web.HTTPError(404)
 
         task_id = dataset.task_id
 
@@ -562,7 +559,7 @@ def delete(self, dataset_id, testcase_id):
 
         # Protect against URLs providing incompatible parameters.
         if dataset is not testcase.dataset:
-            raise tornado_web.HTTPError(404)
+            raise tornado.web.HTTPError(404)
 
         task_id = testcase.dataset.task_id
 

cms/server/admin/handlers/task.py

@@ -36,10 +36,7 @@
     # Monkey-patch: Tornado 4.5.3 does not work on Python 3.11 by default
     collections.MutableMapping = collections.abc.MutableMapping
 
-try:
-    import tornado4.web as tornado_web
-except ImportError:
-    import tornado.web as tornado_web
+import tornado.web
 
 from cms.db import Attachment, Dataset, Session, Statement, Submission, Task
 from cmscommon.datetime import make_datetime
@@ -296,7 +293,7 @@ def delete(self, task_id, statement_id):
 
         # Protect against URLs providing incompatible parameters.
         if task is not statement.task:
-            raise tornado_web.HTTPError(404)
+            raise tornado.web.HTTPError(404)
 
         self.sql_session.delete(statement)
         self.try_commit()
@@ -368,7 +365,7 @@ def delete(self, task_id, attachment_id):
 
         # Protect against URLs providing incompatible parameters.
         if attachment.task is not task:
-            raise tornado_web.HTTPError(404)
+            raise tornado.web.HTTPError(404)
 
         self.sql_session.delete(attachment)
         self.try_commit()

cms/server/contest/handlers/base.py

@@ -42,10 +42,7 @@
     # Monkey-patch: Tornado 4.5.3 does not work on Python 3.11 by default
     collections.MutableMapping = collections.abc.MutableMapping
 
-try:
-    import tornado4.web as tornado_web
-except ImportError:
-    import tornado.web as tornado_web
+import tornado.web
 from werkzeug.datastructures import LanguageAccept
 from werkzeug.http import parse_accept_header
 
@@ -159,7 +156,7 @@ def render_params(self) -> dict:
 
     def write_error(self, status_code, **kwargs):
         if "exc_info" in kwargs and \
-                kwargs["exc_info"][0] != tornado_web.HTTPError:
+                kwargs["exc_info"][0] != tornado.web.HTTPError:
             exc_info = kwargs["exc_info"]
             logger.error(
                 "Uncaught exception (%r) while processing a request: %s",

cms/server/contest/handlers/communication.py

@@ -36,10 +36,7 @@
     # Monkey-patch: Tornado 4.5.3 does not work on Python 3.11 by default
     collections.MutableMapping = collections.abc.MutableMapping
 
-try:
-    import tornado4.web as tornado_web
-except ImportError:
-    import tornado.web as tornado_web
+import tornado.web
 
 from cms.server import multi_contest
 from cms.server.contest.communication import accept_question, \
@@ -60,7 +57,7 @@ class CommunicationHandler(ContestHandler):
     and the contest managers..
 
     """
-    @tornado_web.authenticated
+    @tornado.web.authenticated
     @multi_contest
     def get(self):
         self.render("communication.html", **self.r_params)
@@ -70,7 +67,7 @@ class QuestionHandler(ContestHandler):
     """Called when the user submits a question.
 
     """
-    @tornado_web.authenticated
+    @tornado.web.authenticated
     @multi_contest
     def post(self):
         try:
@@ -79,7 +76,7 @@ def post(self):
                             self.get_argument("question_text", ""))
             self.sql_session.commit()
         except QuestionsNotAllowed:
-            raise tornado_web.HTTPError(404)
+            raise tornado.web.HTTPError(404)
         except UnacceptableQuestion as e:
             self.notify_error(e.subject, e.text, e.text_params)
         else:

cms/server/contest/handlers/contest.py

@@ -44,10 +44,7 @@
     # Monkey-patch: Tornado 4.5.3 does not work on Python 3.11 by default
     collections.MutableMapping = collections.abc.MutableMapping
 
-try:
-    import tornado4.web as tornado_web
-except ImportError:
-    import tornado.web as tornado_web
+import tornado.web
 
 from cms import config, TOKEN_MODE_MIXED
 from cms.db import Contest, Submission, Task, UserTest, contest
@@ -126,7 +123,7 @@ def choose_contest(self):
                 # the one from the base class is enough to display a 404 page.
                 super().prepare()
                 self.r_params = super().render_params()
-                raise tornado_web.HTTPError(404)
+                raise tornado.web.HTTPError(404)
         else:
             # Select the contest specified on the command line
             self.contest = Contest.get_from_id(
@@ -164,7 +161,7 @@ def get_current_user(self) -> Participation | None:
         authorization_header = self.request.headers.get(
             "X-CMS-Authorization", None)
         if authorization_header is not None:
-            authorization_header = tornado_web.decode_signed_value(self.application.settings["cookie_secret"],
+            authorization_header = tornado.web.decode_signed_value(self.application.settings["cookie_secret"],
                                                                    cookie_name, authorization_header)
 
         try: