saferepr: handle BaseExceptions (pytest-dev#6047)

changelog/6047.bugfix.rst

@@ -0,0 +1 @@
+BaseExceptions are handled in ``saferepr``, which includes ``pytest.fail.Exception`` etc.

src/_pytest/_io/saferepr.py

@@ -3,14 +3,24 @@
 from typing import Any
 
 
-def _format_repr_exception(exc: Exception, obj: Any) -> str:
-    exc_name = type(exc).__name__
+def _try_repr_or_str(obj):
     try:
-        exc_info = str(exc)
-    except Exception:
-        exc_info = "unknown"
-    return '<[{}("{}") raised in repr()] {} object at 0x{:x}>'.format(
-        exc_name, exc_info, obj.__class__.__name__, id(obj)
+        return repr(obj)
+    except (KeyboardInterrupt, SystemExit):
+        raise
+    except BaseException:
+        return '{}("{}")'.format(type(obj).__name__, obj)
+
+
+def _format_repr_exception(exc: BaseException, obj: Any) -> str:
+    try:
+        exc_info = _try_repr_or_str(exc)
+    except (KeyboardInterrupt, SystemExit):
+        raise
+    except BaseException as exc:
+        exc_info = "unpresentable exception ({})".format(_try_repr_or_str(exc))
+    return "<[{} raised in repr()] {} object at 0x{:x}>".format(
+        exc_info, obj.__class__.__name__, id(obj)
     )
 
 
@@ -35,14 +45,18 @@ def __init__(self, maxsize: int) -> None:
     def repr(self, x: Any) -> str:
         try:
             s = super().repr(x)
-        except Exception as exc:
+        except (KeyboardInterrupt, SystemExit):
+            raise
+        except BaseException as exc:
             s = _format_repr_exception(exc, x)
         return _ellipsize(s, self.maxsize)
 
     def repr_instance(self, x: Any, level: int) -> str:
         try:
             s = repr(x)
-        except Exception as exc:
+        except (KeyboardInterrupt, SystemExit):
+            raise
+        except BaseException as exc:
             s = _format_repr_exception(exc, x)
         return _ellipsize(s, self.maxsize)
 

testing/code/test_excinfo.py

@@ -584,7 +584,7 @@ def __repr__(self):
         reprlocals = p.repr_locals(loc)
         assert reprlocals.lines
         assert reprlocals.lines[0] == "__builtins__ = <builtins>"
-        assert '[NotImplementedError("") raised in repr()]' in reprlocals.lines[1]
+        assert "[NotImplementedError() raised in repr()]" in reprlocals.lines[1]
 
     def test_repr_local_with_exception_in_class_property(self):
         class ExceptionWithBrokenClass(Exception):
@@ -602,7 +602,7 @@ def __repr__(self):
         reprlocals = p.repr_locals(loc)
         assert reprlocals.lines
         assert reprlocals.lines[0] == "__builtins__ = <builtins>"
-        assert '[ExceptionWithBrokenClass("") raised in repr()]' in reprlocals.lines[1]
+        assert "[ExceptionWithBrokenClass() raised in repr()]" in reprlocals.lines[1]
 
     def test_repr_local_truncated(self):
         loc = {"l": [i for i in range(10)]}

testing/io/test_saferepr.py

@@ -1,3 +1,4 @@
+import pytest
 from _pytest._io.saferepr import saferepr
 
 
@@ -40,9 +41,81 @@ class BrokenReprException(Exception):
     assert "TypeError" in s
     assert "TypeError" in saferepr(BrokenRepr("string"))
 
-    s2 = saferepr(BrokenRepr(BrokenReprException("omg even worse")))
-    assert "NameError" not in s2
-    assert "unknown" in s2
+    none = None
+    try:
+        none()
+    except BaseException as exc:
+        exp_exc = repr(exc)
+    obj = BrokenRepr(BrokenReprException("omg even worse"))
+    s2 = saferepr(obj)
+    assert s2 == (
+        "<[unpresentable exception ({!s}) raised in repr()] BrokenRepr object at 0x{:x}>".format(
+            exp_exc, id(obj)
+        )
+    )
+
+
+def test_baseexception():
+    """Test saferepr() with BaseExceptions, which includes pytest outcomes."""
+
+    class RaisingOnStrRepr(BaseException):
+        def __init__(self, exc_types):
+            self.exc_types = exc_types
+
+        def raise_exc(self, *args):
+            try:
+                self.exc_type = self.exc_types.pop(0)
+            except IndexError:
+                pass
+            if hasattr(self.exc_type, "__call__"):
+                raise self.exc_type(*args)
+            raise self.exc_type
+
+        def __str__(self):
+            self.raise_exc("__str__")
+
+        def __repr__(self):
+            self.raise_exc("__repr__")
+
+    class BrokenObj:
+        def __init__(self, exc):
+            self.exc = exc
+
+        def __repr__(self):
+            raise self.exc
+
+        __str__ = __repr__
+
+    baseexc_str = BaseException("__str__")
+    obj = BrokenObj(RaisingOnStrRepr([BaseException]))
+    assert saferepr(obj) == (
+        "<[unpresentable exception ({!r}) "
+        "raised in repr()] BrokenObj object at 0x{:x}>".format(baseexc_str, id(obj))
+    )
+    obj = BrokenObj(RaisingOnStrRepr([RaisingOnStrRepr([BaseException])]))
+    assert saferepr(obj) == (
+        "<[{!r} raised in repr()] BrokenObj object at 0x{:x}>".format(
+            baseexc_str, id(obj)
+        )
+    )
+
+    with pytest.raises(KeyboardInterrupt):
+        saferepr(BrokenObj(KeyboardInterrupt()))
+
+    with pytest.raises(SystemExit):
+        saferepr(BrokenObj(SystemExit()))
+
+    with pytest.raises(KeyboardInterrupt):
+        saferepr(BrokenObj(RaisingOnStrRepr([KeyboardInterrupt])))
+
+    with pytest.raises(SystemExit):
+        saferepr(BrokenObj(RaisingOnStrRepr([SystemExit])))
+
+    with pytest.raises(KeyboardInterrupt):
+        print(saferepr(BrokenObj(RaisingOnStrRepr([BaseException, KeyboardInterrupt]))))
+
+    with pytest.raises(SystemExit):
+        saferepr(BrokenObj(RaisingOnStrRepr([BaseException, SystemExit])))
 
 
 def test_buggy_builtin_repr():

testing/test_session.py

@@ -102,15 +102,20 @@ def test_broken_repr(self, testdir):
         p = testdir.makepyfile(
             """
             import pytest
+
+            class reprexc(BaseException):
+                def __str__(self):
+                    return "Ha Ha fooled you, I'm a broken repr()."
+
             class BrokenRepr1(object):
                 foo=0
                 def __repr__(self):
-                    raise Exception("Ha Ha fooled you, I'm a broken repr().")
+                    raise reprexc
 
             class TestBrokenClass(object):
                 def test_explicit_bad_repr(self):
                     t = BrokenRepr1()
-                    with pytest.raises(Exception, match="I'm a broken repr"):
+                    with pytest.raises(BaseException, match="broken repr"):
                         repr(t)
 
                 def test_implicit_bad_repr1(self):
@@ -123,12 +128,7 @@ def test_implicit_bad_repr1(self):
         passed, skipped, failed = reprec.listoutcomes()
         assert (len(passed), len(skipped), len(failed)) == (1, 0, 1)
         out = failed[0].longrepr.reprcrash.message
-        assert (
-            out.find(
-                """[Exception("Ha Ha fooled you, I'm a broken repr().") raised in repr()]"""
-            )
-            != -1
-        )
+        assert out.find("<[reprexc() raised in repr()] BrokenRepr1") != -1
 
     def test_broken_repr_with_showlocals_verbose(self, testdir):
         p = testdir.makepyfile(
@@ -151,7 +151,7 @@ def test_repr_error():
         assert repr_locals.lines
         assert len(repr_locals.lines) == 1
         assert repr_locals.lines[0].startswith(
-            'x          = <[NotImplementedError("") raised in repr()] ObjWithErrorInRepr'
+            "x          = <[NotImplementedError() raised in repr()] ObjWithErrorInRepr"
         )
 
     def test_skip_file_by_conftest(self, testdir):