Handle Prolog engine exceptions in PrologSession

1 files changed, 17 insertions, 11 deletions

diff --git a/server/prolog_session.py b/server/prolog_session.py
index cd54e20..c5fa1de 100644
--- a/server/prolog_session.py
+++ b/server/prolog_session.py
@@ -2,6 +2,7 @@
 
 import operator
 import threading
+
 import prolog.engine
 import server
 import server.user_session
@@ -101,17 +102,20 @@ class PrologSession(server.LanguageSession):
                               if pp != (p.group, p.identifier)]
 
         hints = []
-        # check if the program is already correct
-        passed, _ = problem_module.test(program, solved_problems)
-        if passed:
-            hints = [{'id': 'program_already_correct'}]
-
-        if not hints and hasattr(language_module, 'hint'):
-            hints = language_module.hint(program, solved_problems)
-        if not hints and hasattr(problem_module, 'hint'):
-            hints = problem_module.hint(program, solved_problems)
-        if not hints:
-            hints = [{'id': 'no_hint'}]
+        try:
+            # check if the program is already correct
+            passed, _ = problem_module.test(program, solved_problems)
+            if passed:
+                hints = [{'id': 'program_already_correct'}]
+
+            if not hints and hasattr(language_module, 'hint'):
+                hints = language_module.hint(program, solved_problems)
+            if not hints and hasattr(problem_module, 'hint'):
+                hints = problem_module.hint(program, solved_problems)
+            if not hints:
+                hints = [{'id': 'no_hint'}]
+        except Exception as ex:
+            hints = [{'id': 'system_error', 'args': {'message': str(ex)}}]
 
         self._instantiate_and_save_hints(language_module, problem_module, hints)
         return hints
@@ -130,6 +134,8 @@ class PrologSession(server.LanguageSession):
                 session.update_solution(problem_id, done=True)
         except AttributeError as ex:
             hints = [{'id': 'system_error', 'args': {'message': 'test function does not exist'}}]
+        except Exception as ex:
+            hints = [{'id': 'system_error', 'args': {'message': str(ex)}}]
 
         self._instantiate_and_save_hints(language_module, problem_module, hints)
         return hints