Check for syntax errors in python_session.hint

1 files changed, 9 insertions, 0 deletions

diff --git a/server/python_session.py b/server/python_session.py
index 4c4a781..011adc3 100644
--- a/server/python_session.py
+++ b/server/python_session.py
@@ -1,7 +1,9 @@
 # coding=utf-8
 
+import ast
 import multiprocessing.managers
 import threading
+
 import server.user_session
 from db.models import Problem
 from . import problems
@@ -67,6 +69,13 @@ class PythonSession(object):
         language, problem_group, problem = Problem.get_identifier(problem_id)
         problem_module = problems.load_problem(language, problem_group, problem, 'common')
 
+        # Check syntax.
+        try:
+            tree = ast.parse(program, filename='user')
+        except SyntaxError as ex:
+            error_msg = '{}{}^\n{}'.format(ex.text, ' '*(ex.offset-1), ex.msg)
+            return [{'id': 'syntax_error', 'args': {'lineno': ex.lineno, 'message': error_msg}}]
+
         # Try problem-specific hints.
         if hasattr(problem_module, 'hint'):
             hints = problem_module.hint(session, program)