From a3dbdfc6870684580a17b11f6b04126303962633 Mon Sep 17 00:00:00 2001
From: Zac Hatfield-Dodds <Zac-HD@users.noreply.github.com>
Date: Fri, 25 May 2018 18:32:13 +1000
Subject: [PATCH] Improve error for in_(a_string) with a non-string value
 (#383)

* Improve error for in_(a_string) with a non-string value

* Tighten exception handling and test description

* Improve changelog for Hynek

* Final changelog edit
---
 changelog.d/383.change.rst |  2 ++
 src/attr/validators.py     |  7 ++++++-
 tests/test_validators.py   | 13 +++++++++++++
 3 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 changelog.d/383.change.rst

diff --git a/changelog.d/383.change.rst b/changelog.d/383.change.rst
new file mode 100644
index 00000000..6600b5b3
--- /dev/null
+++ b/changelog.d/383.change.rst
@@ -0,0 +1,2 @@
+``attr.validators.in_()`` now raises a ``ValueError`` with a useful message even if the options are a string and the value is not a string.
+This previously raised a ``TypeError``, like ``1 in "abc"``.
diff --git a/src/attr/validators.py b/src/attr/validators.py
index f8892fcd..4904e616 100644
--- a/src/attr/validators.py
+++ b/src/attr/validators.py
@@ -135,7 +135,12 @@ class _InValidator(object):
     options = attrib()
 
     def __call__(self, inst, attr, value):
-        if value not in self.options:
+        try:
+            in_options = value in self.options
+        except TypeError as e:  # e.g. `1 in "abc"`
+            in_options = False
+
+        if not in_options:
             raise ValueError(
                 "'{name}' must be in {options!r} (got {value!r})"
                 .format(name=attr.name, options=self.options, value=value)
diff --git a/tests/test_validators.py b/tests/test_validators.py
index 0e67f991..4d24ce95 100644
--- a/tests/test_validators.py
+++ b/tests/test_validators.py
@@ -243,6 +243,19 @@ class TestIn_(object):
             "'test' must be in [1, 2, 3] (got None)",
         ) == e.value.args
 
+    def test_fail_with_string(self):
+        """
+        Raise ValueError if the value is outside our options when the
+        options are specified as a string and the value is not a string.
+        """
+        v = in_("abc")
+        a = simple_attr("test")
+        with pytest.raises(ValueError) as e:
+            v(None, a, None)
+        assert (
+            "'test' must be in 'abc' (got None)",
+        ) == e.value.args
+
     def test_repr(self):
         """
         Returned validator has a useful `__repr__`.