Fix has expr msg to not always say "with values"

pythonwhat/check_funcs.py

@@ -441,7 +441,7 @@ def parse_tree(n):
 
     return state
 
-def has_expr(incorrect_msg="FMT:Unexpected expression {test}: expected `{sol_eval}`, got `{stu_eval}` with values{extra_env}.",
+def has_expr(incorrect_msg="__JINJA__:Unexpected expression {{test}}: expected `{{sol_eval}}`, got `{{stu_eval}}`{{' with values ' + extra_env if extra_env}}.",
              error_msg="Running an expression in the student process caused an issue.",
              undefined_msg="FMT:Have you defined `{name}` without errors?",
              extra_env=None,
@@ -451,6 +451,7 @@ def has_expr(incorrect_msg="FMT:Unexpected expression {test}: expected `{sol_eva
              keep_objs_in_env=None,
              name=None,
              highlight=None,
+             copy=True,
              state=None,
              test=None):
     """Run student and solution code, compare returned value, printed output, or errors.
@@ -496,6 +497,7 @@ def has_expr(incorrect_msg="FMT:Unexpected expression {test}: expected `{sol_eva
                        expr_code = expr_code,
                        keep_objs_in_env = keep_objs_in_env,
                        name=name,
+                       copy=copy,
                        do_exec = True if test == 'output' else False)
 
     eval_sol, str_sol = get_func(tree = state.solution_tree,
@@ -515,7 +517,7 @@ def has_expr(incorrect_msg="FMT:Unexpected expression {test}: expected `{sol_eva
     # kwargs ---
     fmt_kwargs = {'stu_part': state.student_parts, 'sol_part': state.solution_parts, 
                   'name': name, 'test': test,
-                  'extra_env': " "+str(extra_env or ""), 'context_vals': context_vals}
+                  'extra_env': str(extra_env) if extra_env else "", 'context_vals': context_vals}
     fmt_kwargs['stu_eval'] = utils.shorten_str(str(eval_stu))
     fmt_kwargs['sol_eval'] = utils.shorten_str(str(eval_sol))
 

pythonwhat/tasks.py

@@ -5,7 +5,7 @@
 import pythonwhat
 import ast
 import inspect
-import copy
+from copy import deepcopy
 from pickle import PicklingError
 from pythonwhat.utils_env import set_context_vals, assign_from_ast
 from contextlib import contextmanager
@@ -330,17 +330,10 @@ def get_error(f, *args, **kwargs):
 def taskRunEval(tree,
                 process, shell, 
                 keep_objs_in_env = None, extra_env = None, context=None, context_vals=None, 
-                pre_code = "", expr_code = "", name="", tempname='_evaluation_object_', do_exec=False, 
-                call=None):
-    new_env = utils.copy_env(get_env(shell.user_ns), keep_objs_in_env)
-    if extra_env is not None:
-        new_env.update(copy.deepcopy(extra_env))
-    if context is not None: 
-        set_context_vals(new_env, context, context_vals)
+                pre_code = "", expr_code = "", name="", copy=True, tempname='_evaluation_object_', 
+                do_exec=False, call=None):
     try: 
-        # Execute pre_code if specified
-        if pre_code: exec(pre_code, new_env)
-
+        # Prepare code --------------------------------------------------------
         # If no name given, the object of interest is the output of eval
         # otherwise, we'll use name to get the object from the environment
         if not (name or do_exec):
@@ -353,6 +346,22 @@ def taskRunEval(tree,
         if expr_code: code = expr_code
         else:         code = compile(tree, "<script>", mode)
 
+        # Set up environment --------------------------------------------------
+        # avoid deepy copy if specified, or just looking up variable by name
+        if not copy or (isinstance(tree, ast.Name) and isinstance(tree.ctx, ast.Load)):
+            new_env = dict(get_env(shell.user_ns))
+        else:
+            new_env = utils.copy_env(get_env(shell.user_ns), keep_objs_in_env)
+
+        if extra_env is not None:
+            new_env.update(deepcopy(extra_env))
+        if context is not None: 
+            set_context_vals(new_env, context, context_vals)
+
+        # Execute code --------------------------------------------------------
+        # Run pre_code if specified
+        if pre_code: exec(pre_code, new_env)
+
         if mode == 'eval': 
             obj = eval(code, new_env)
         else:       

tests/test_test_expression_result.py

@@ -21,5 +21,19 @@ def test_pass(self):
         sct_payload = helper.run(self.data)
         self.assertTrue(sct_payload['correct'])
 
+    def test_no_copy_bad_sct_passes(self):
+        self.data["DC_SOLUTION"] = "a = [2]"
+        self.data["DC_CODE"] = "a = [1]"
+        self.data["DC_SCT"] = "Ex().has_equal_value(expr_code = 'a[0] = 3', name = 'a', copy = False).has_equal_value(expr_code = 'a', name = 'a')"
+        sct_payload = helper.run(self.data)
+        self.assertTrue(sct_payload['correct'])
+
+    def test_copy_sct_fails(self):
+        self.data["DC_SOLUTION"] = "a = [2]"
+        self.data["DC_CODE"] = "a = [1]"
+        self.data["DC_SCT"] = "Ex().has_equal_value(expr_code = 'a[0] = 3', name = 'a', copy = True).has_equal_value(name = 'a')"
+        sct_payload = helper.run(self.data)
+        self.assertFalse(sct_payload['correct'])
+
 if __name__ == "__main__":
     unittest.main()