Merge pull request #7082 from symonk/4583-better-ux-with-eval-fails

Gracefully handle eval() failure(s) for marker expressions

AUTHORS

@@ -246,6 +246,7 @@ Segev Finer
 Serhii Mozghovyi
 Seth Junot
 Simon Gomizelj
+Simon Kerr
 Skylar Downes
 Srinivas Reddy Thatiparthy
 Stefan Farmbauer

changelog/4583.bugfix.rst

@@ -0,0 +1 @@
+Prevent crashing and provide a user-friendly error when a marker expression (-m) invoking of eval() raises any exception.

src/_pytest/mark/legacy.py

@@ -84,8 +84,8 @@ def matchmark(colitem, markexpr):
     """Tries to match on any marker names, attached to the given colitem."""
     try:
         return eval(markexpr, {}, MarkMapping.from_item(colitem))
-    except SyntaxError as e:
-        raise SyntaxError(str(e) + "\nMarker expression must be valid Python!")
+    except Exception:
+        raise UsageError("Wrong expression passed to '-m': {}".format(markexpr))
 
 
 def matchkeyword(colitem, keywordexpr):

testing/test_mark.py

@@ -601,18 +601,6 @@ class TestFunctional:
         deselected_tests = dlist[0].items
         assert len(deselected_tests) == 2
 
-    def test_invalid_m_option(self, testdir):
-        testdir.makepyfile(
-            """
-            def test_a():
-                pass
-        """
-        )
-        result = testdir.runpytest("-m bogus/")
-        result.stdout.fnmatch_lines(
-            ["INTERNALERROR> Marker expression must be valid Python!"]
-        )
-
     def test_keywords_at_node_level(self, testdir):
         testdir.makepyfile(
             """
@@ -1022,3 +1010,20 @@ def test_pytest_param_id_requires_string():
 @pytest.mark.parametrize("s", (None, "hello world"))
 def test_pytest_param_id_allows_none_or_string(s):
     assert pytest.param(id=s)
+
+
+@pytest.mark.parametrize("expr", ("NOT internal_err", "NOT (internal_err)", "bogus/"))
+def test_marker_expr_eval_failure_handling(testdir, expr):
+    foo = testdir.makepyfile(
+        """
+        import pytest
+
+        @pytest.mark.internal_err
+        def test_foo():
+            pass
+        """
+    )
+    expected = "ERROR: Wrong expression passed to '-m': {}".format(expr)
+    result = testdir.runpytest(foo, "-m", expr)
+    result.stderr.fnmatch_lines([expected])
+    assert result.ret == ExitCode.USAGE_ERROR