From 1ae9fcc6b1f83bad403da4f6cc3e69ddb94d49d4 Mon Sep 17 00:00:00 2001
From: Claudiu Popa <pcmanticore@gmail.com>
Date: Tue, 19 Feb 2019 09:13:07 +0100
Subject: Protect against `NonDeducibleTypeHierarchy` when calling semi-private
 `is_subtype`

`astroid.helpers.is_subtype` raises `NonDeducibleTypeHierarchy` when it cannot infer
the base classes of the given types, but that makes sense in its context given that
the method is mostly used to inform the inference process about the hierarchy of classes.
Doesn't make that much sense for ``pylint`` itself, which is why we're handling the
exception here, rather than in ``astroid``

Close PyCQA/astroid#644
---
 ChangeLog                                         | 10 +++++++++
 pylint/checkers/utils.py                          |  8 ++++++--
 pylint/test/functional/try_except_raise_crash.py  | 25 +++++++++++++++++++++++
 pylint/test/functional/try_except_raise_crash.txt |  1 +
 4 files changed, 42 insertions(+), 2 deletions(-)
 create mode 100644 pylint/test/functional/try_except_raise_crash.py
 create mode 100644 pylint/test/functional/try_except_raise_crash.txt

diff --git a/ChangeLog b/ChangeLog
index 4e7fc9874..dad70c637 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,16 @@ What's New in Pylint 2.3.0?
 
 Release date: TBA
 
+* Protect against `NonDeducibleTypeHierarchy` when calling semi-private `is_subtype`
+
+  `astroid.helpers.is_subtype` raises `NonDeducibleTypeHierarchy` when it cannot infer
+  the base classes of the given types, but that makes sense in its context given that
+  the method is mostly used to inform the inference process about the hierarchy of classes.
+  Doesn't make that much sense for ``pylint`` itself, which is why we're handling the
+  exception here, rather than in ``astroid``
+
+  Close PyCQA/astroid#644
+
 * Added a new command line option ``list-groups`` for listing all the check groups ``pylint`` knows about.
 
 * Allow ``BaseException`` for emitting ``broad-except``, just like ``Exception``.
diff --git a/pylint/checkers/utils.py b/pylint/checkers/utils.py
index 3cc292115..b4129389f 100644
--- a/pylint/checkers/utils.py
+++ b/pylint/checkers/utils.py
@@ -40,6 +40,7 @@ from typing import Optional, Iterable, Tuple, Callable, Set, Union, Match, Dict,
 import _string  # pylint: disable=wrong-import-position, wrong-import-order
 
 import astroid
+from astroid.exceptions import _NonDeducibleTypeHierarchy
 from astroid import bases as _bases
 from astroid import scoped_nodes
 
@@ -1202,6 +1203,9 @@ def is_subclass_of(child: astroid.ClassDef, parent: astroid.ClassDef) -> bool:
         return False
 
     for ancestor in child.ancestors():
-        if astroid.helpers.is_subtype(ancestor, parent):
-            return True
+        try:
+            if astroid.helpers.is_subtype(ancestor, parent):
+                return True
+        except _NonDeducibleTypeHierarchy:
+            continue
     return False
diff --git a/pylint/test/functional/try_except_raise_crash.py b/pylint/test/functional/try_except_raise_crash.py
new file mode 100644
index 000000000..7a1f8d972
--- /dev/null
+++ b/pylint/test/functional/try_except_raise_crash.py
@@ -0,0 +1,25 @@
+# pylint: disable=missing-docstring,too-many-ancestors, broad-except
+import collections.abc
+from typing import TYPE_CHECKING, Any, MutableMapping
+
+if TYPE_CHECKING:
+    BaseClass = MutableMapping[str, Any]
+else:
+    BaseClass = collections.abc.MutableMapping
+
+
+class TestBaseException(BaseClass):
+    pass
+
+
+class TestException(TestBaseException):
+    pass
+
+
+def test():
+    try:
+        1 / 0
+    except TestException:  # [try-except-raise]
+        raise
+    except Exception:
+        pass
diff --git a/pylint/test/functional/try_except_raise_crash.txt b/pylint/test/functional/try_except_raise_crash.txt
new file mode 100644
index 000000000..a99476ab9
--- /dev/null
+++ b/pylint/test/functional/try_except_raise_crash.txt
@@ -0,0 +1 @@
+try-except-raise:22:test:The except handler raises immediately
-- 
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