From 1c4decd8429d98d753160a43d0f4cc5097b74b72 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Fri, 15 Feb 2019 18:43:29 -0500
Subject: [PATCH 01/33] interval constructor logic modified and error handling
 for is_dtype updated to include new TypeError

---
 pandas/core/dtypes/dtypes.py | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index 640d43f3b0e03..af04fb3038c5a 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -893,11 +893,15 @@ def __new__(cls, subtype=None):
                 m = cls._match.search(subtype)
                 if m is not None:
                     subtype = m.group('subtype')
-
-            try:
-                subtype = pandas_dtype(subtype)
-            except TypeError:
-                raise TypeError("could not construct IntervalDtype")
+                else:
+                    # if no match found, a bad datatype was passed
+                    msg = ('category, object, and string subtypes are not supported '
+                    'for IntervalDtype')
+                    raise TypeError(msg)
+        try:
+            subtype = pandas_dtype(subtype)
+        except TypeError:
+            raise TypeError("could not construct IntervalDtype")
 
         if is_categorical_dtype(subtype) or is_string_dtype(subtype):
             # GH 19016
@@ -978,7 +982,7 @@ def is_dtype(cls, dtype):
                         return True
                     else:
                         return False
-                except ValueError:
+                except (ValueError, TypeError):
                     return False
             else:
                 return False

From d52c6317eadb0e30f7f85cdd339b76a9a3db0b20 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Fri, 15 Feb 2019 18:47:39 -0500
Subject: [PATCH 02/33] formatting updates for error msg

---
 pandas/core/dtypes/dtypes.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index af04fb3038c5a..cd96413a71500 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -895,8 +895,8 @@ def __new__(cls, subtype=None):
                     subtype = m.group('subtype')
                 else:
                     # if no match found, a bad datatype was passed
-                    msg = ('category, object, and string subtypes are not supported '
-                    'for IntervalDtype')
+                    msg = ('category, object, and string subtypes are not '
+                           'supported for IntervalDtype')
                     raise TypeError(msg)
         try:
             subtype = pandas_dtype(subtype)

From 953823e7535a19eaa109f837e4754572f39873f2 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Sun, 17 Feb 2019 13:45:11 -0500
Subject: [PATCH 03/33] subtype check logic implemented for Interval dtype

---
 pandas/core/dtypes/dtypes.py | 34 +++++++++++++++++++++-------------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index cd96413a71500..07e014b14f7bc 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -893,20 +893,28 @@ def __new__(cls, subtype=None):
                 m = cls._match.search(subtype)
                 if m is not None:
                     subtype = m.group('subtype')
-                else:
-                    # if no match found, a bad datatype was passed
-                    msg = ('category, object, and string subtypes are not '
-                           'supported for IntervalDtype')
-                    raise TypeError(msg)
-        try:
-            subtype = pandas_dtype(subtype)
-        except TypeError:
-            raise TypeError("could not construct IntervalDtype")
-
-        if is_categorical_dtype(subtype) or is_string_dtype(subtype):
-            # GH 19016
+        
+        # check subtype is numeric, datetime, or timedelta
+        valid_subtype = False
+        try: 
+            np.issubdtype(subtype, np.number)
+            valid_subtype = True
+        except:
+            pass
+        try: 
+            np.issubdtype(subdtype, np.datetime64)
+            valid_subtype = True
+        except:
+            pass
+        try: 
+            np.issubdtype(subtype, np.timedelta64)
+            valid_subtype = True
+        except:
+            pass
+         
+        if not valid_subtype: 
             msg = ('category, object, and string subtypes are not supported '
-                   'for IntervalDtype')
+               'for IntervalDtype')
             raise TypeError(msg)
 
         try:

From 8edbbd8dda40c850efc578afbf15532c37cd2d81 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Sun, 17 Feb 2019 13:51:11 -0500
Subject: [PATCH 04/33] tests added to ensure 
 pd.api.types.IntervalDtype.is_dtype(IntervalA) returns false

---
 pandas/tests/dtypes/test_dtypes.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pandas/tests/dtypes/test_dtypes.py b/pandas/tests/dtypes/test_dtypes.py
index 710f215686eab..6be06412e952b 100644
--- a/pandas/tests/dtypes/test_dtypes.py
+++ b/pandas/tests/dtypes/test_dtypes.py
@@ -559,6 +559,7 @@ def test_is_dtype(self):
         assert not IntervalDtype.is_dtype('U')
         assert not IntervalDtype.is_dtype('S')
         assert not IntervalDtype.is_dtype('foo')
+        assert not IntervalDtype.is_dtype('IntervalA')
         assert not IntervalDtype.is_dtype(np.object_)
         assert not IntervalDtype.is_dtype(np.int64)
         assert not IntervalDtype.is_dtype(np.float64)

From 8e543084ef9b6c680e91e5ea9736581a3972ddda Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Sun, 17 Feb 2019 13:53:34 -0500
Subject: [PATCH 05/33] tests added to ensure *
 pd.api.types.IntervalDtype(IntervalA) throws TypeError

---
 pandas/tests/dtypes/test_dtypes.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pandas/tests/dtypes/test_dtypes.py b/pandas/tests/dtypes/test_dtypes.py
index 6be06412e952b..7673b4d60ea44 100644
--- a/pandas/tests/dtypes/test_dtypes.py
+++ b/pandas/tests/dtypes/test_dtypes.py
@@ -503,7 +503,8 @@ def test_construction_generic(self, subtype):
     @pytest.mark.parametrize('subtype', [
         CategoricalDtype(list('abc'), False),
         CategoricalDtype(list('wxyz'), True),
-        object, str, '<U10', 'interval[category]', 'interval[object]'])
+        object, str, '<U10', 'interval[category]', 'interval[object]',
+        'IntervalA'])
     def test_construction_not_supported(self, subtype):
         # GH 19016
         msg = ('category, object, and string subtypes are not supported '

From eec50131414bb7e5ac3a60313204bb64d2876cae Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Sun, 17 Feb 2019 13:59:10 -0500
Subject: [PATCH 06/33] test added to ensure
 pd.api.types.IntervalDtype.construct_from_string(IntervalA) throws TypeError

---
 pandas/tests/dtypes/test_dtypes.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/pandas/tests/dtypes/test_dtypes.py b/pandas/tests/dtypes/test_dtypes.py
index 7673b4d60ea44..00911a34a1672 100644
--- a/pandas/tests/dtypes/test_dtypes.py
+++ b/pandas/tests/dtypes/test_dtypes.py
@@ -533,10 +533,11 @@ def test_construction_from_string_errors(self, string):
             IntervalDtype.construct_from_string(string)
 
     @pytest.mark.parametrize('string', [
-        'interval[foo]'])
+        'interval[foo]', 'IntervalA'])
     def test_construction_from_string_error_subtype(self, string):
         # this is an invalid subtype
-        msg = 'could not construct IntervalDtype'
+        msg = ('category, object, and string subtypes are not supported '
+               'for IntervalDtype')
 
         with pytest.raises(TypeError, match=msg):
             IntervalDtype.construct_from_string(string)

From 708a7403f2b473bfcdca41561fa09faa25e86f2d Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Sun, 17 Feb 2019 14:02:08 -0500
Subject: [PATCH 07/33] PEP8 style issues resolved

---
 pandas/core/dtypes/dtypes.py | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index 07e014b14f7bc..bd63c6e4bc4c6 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -893,28 +893,28 @@ def __new__(cls, subtype=None):
                 m = cls._match.search(subtype)
                 if m is not None:
                     subtype = m.group('subtype')
-        
+
         # check subtype is numeric, datetime, or timedelta
         valid_subtype = False
-        try: 
+        try:
             np.issubdtype(subtype, np.number)
             valid_subtype = True
-        except:
+        except TypeError:
             pass
-        try: 
+        try:
             np.issubdtype(subdtype, np.datetime64)
             valid_subtype = True
-        except:
+        except TypeError:
             pass
-        try: 
+        try:
             np.issubdtype(subtype, np.timedelta64)
             valid_subtype = True
-        except:
+        except TypeError:
             pass
          
         if not valid_subtype: 
             msg = ('category, object, and string subtypes are not supported '
-               'for IntervalDtype')
+                   'for IntervalDtype')
             raise TypeError(msg)
 
         try:

From 9ae2afc99163430c44b7317b035d304a03f8ade4 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Sun, 17 Feb 2019 14:03:37 -0500
Subject: [PATCH 08/33] more PEP8 style issues resolved

---
 pandas/core/dtypes/dtypes.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index bd63c6e4bc4c6..9f27ece7d352a 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -902,7 +902,7 @@ def __new__(cls, subtype=None):
         except TypeError:
             pass
         try:
-            np.issubdtype(subdtype, np.datetime64)
+            np.issubdtype(subtype, np.datetime64)
             valid_subtype = True
         except TypeError:
             pass
@@ -911,8 +911,8 @@ def __new__(cls, subtype=None):
             valid_subtype = True
         except TypeError:
             pass
-         
-        if not valid_subtype: 
+
+        if not valid_subtype:
             msg = ('category, object, and string subtypes are not supported '
                    'for IntervalDtype')
             raise TypeError(msg)

From 0837c858d0758d657b0e5d96ef5d7c87ce3fcb5b Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Sun, 17 Feb 2019 14:14:32 -0500
Subject: [PATCH 09/33] subtype checking consolidated into for loop

---
 pandas/core/dtypes/dtypes.py | 22 +++++++---------------
 1 file changed, 7 insertions(+), 15 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index 9f27ece7d352a..edb418b92e147 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -896,21 +896,13 @@ def __new__(cls, subtype=None):
 
         # check subtype is numeric, datetime, or timedelta
         valid_subtype = False
-        try:
-            np.issubdtype(subtype, np.number)
-            valid_subtype = True
-        except TypeError:
-            pass
-        try:
-            np.issubdtype(subtype, np.datetime64)
-            valid_subtype = True
-        except TypeError:
-            pass
-        try:
-            np.issubdtype(subtype, np.timedelta64)
-            valid_subtype = True
-        except TypeError:
-            pass
+        for nptype in [np.number, np.datetime64, np.timedelta64]:
+            try:
+                np.issubdtype(subtype, nptype)
+                valid_subtype = True
+                break
+            except TypeError:
+                pass
 
         if not valid_subtype:
             msg = ('category, object, and string subtypes are not supported '

From c0818b66c0cdff101bc6536ab01158ebbe0883c5 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Sun, 17 Feb 2019 15:06:32 -0500
Subject: [PATCH 10/33] logic change to include issubtype must result in True

---
 pandas/core/dtypes/dtypes.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index edb418b92e147..426e7af833003 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -898,9 +898,9 @@ def __new__(cls, subtype=None):
         valid_subtype = False
         for nptype in [np.number, np.datetime64, np.timedelta64]:
             try:
-                np.issubdtype(subtype, nptype)
-                valid_subtype = True
-                break
+                if np.issubdtype(subtype, nptype):
+                    valid_subtype = True
+                    break
             except TypeError:
                 pass
 

From dedba898886cd9f7e39b82eb9057d28a686031cb Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Sun, 17 Feb 2019 16:36:22 -0500
Subject: [PATCH 11/33] logic change for checking datetime and timedelta dtypes

---
 pandas/core/dtypes/dtypes.py | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index 426e7af833003..1cb42b66bb6c4 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -6,7 +6,7 @@
 import pytz
 
 from pandas._libs.interval import Interval
-from pandas._libs.tslibs import NaT, Period, Timestamp, timezones
+from pandas._libs.tslibs import NaT, Period, Timestamp, timezones, Timedelta
 
 from pandas.core.dtypes.generic import (
     ABCCategoricalIndex, ABCDateOffset, ABCIndexClass)
@@ -896,13 +896,26 @@ def __new__(cls, subtype=None):
 
         # check subtype is numeric, datetime, or timedelta
         valid_subtype = False
-        for nptype in [np.number, np.datetime64, np.timedelta64]:
-            try:
-                if np.issubdtype(subtype, nptype):
-                    valid_subtype = True
-                    break
-            except TypeError:
-                pass
+
+        # test for number
+        try:
+            if np.issubdtype(subtype, np.number):
+                valid_subtype = True
+        except TypeError:
+            pass
+        # test for datetime
+        try:
+            DatetimeTZDtype.construct_from_string(subtype)
+            valid_subtype = True
+        except TypeError:
+            pass
+        # test for timedelta
+        try:
+            Timedelta(subtype)
+            valid_subtype = True
+        except ValueError:
+            pass
+
 
         if not valid_subtype:
             msg = ('category, object, and string subtypes are not supported '

From 6914a7b192aafbd9ff75273ebd3f9cb677ed1a70 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Sun, 17 Feb 2019 16:37:24 -0500
Subject: [PATCH 12/33] extra blank line removed

---
 pandas/core/dtypes/dtypes.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index 1cb42b66bb6c4..82722190830f8 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -916,7 +916,6 @@ def __new__(cls, subtype=None):
         except ValueError:
             pass
 
-
         if not valid_subtype:
             msg = ('category, object, and string subtypes are not supported '
                    'for IntervalDtype')

From c53d69cf8a11f2b0616acf42b0f51c2c7b9e8e15 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Sun, 17 Feb 2019 17:42:48 -0500
Subject: [PATCH 13/33] reset to original logic on working branch, only tests
 written remain committed to branch

---
 pandas/core/dtypes/dtypes.py | 32 ++++++++------------------------
 1 file changed, 8 insertions(+), 24 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index 82722190830f8..640d43f3b0e03 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -6,7 +6,7 @@
 import pytz
 
 from pandas._libs.interval import Interval
-from pandas._libs.tslibs import NaT, Period, Timestamp, timezones, Timedelta
+from pandas._libs.tslibs import NaT, Period, Timestamp, timezones
 
 from pandas.core.dtypes.generic import (
     ABCCategoricalIndex, ABCDateOffset, ABCIndexClass)
@@ -894,29 +894,13 @@ def __new__(cls, subtype=None):
                 if m is not None:
                     subtype = m.group('subtype')
 
-        # check subtype is numeric, datetime, or timedelta
-        valid_subtype = False
-
-        # test for number
-        try:
-            if np.issubdtype(subtype, np.number):
-                valid_subtype = True
-        except TypeError:
-            pass
-        # test for datetime
-        try:
-            DatetimeTZDtype.construct_from_string(subtype)
-            valid_subtype = True
-        except TypeError:
-            pass
-        # test for timedelta
-        try:
-            Timedelta(subtype)
-            valid_subtype = True
-        except ValueError:
-            pass
+            try:
+                subtype = pandas_dtype(subtype)
+            except TypeError:
+                raise TypeError("could not construct IntervalDtype")
 
-        if not valid_subtype:
+        if is_categorical_dtype(subtype) or is_string_dtype(subtype):
+            # GH 19016
             msg = ('category, object, and string subtypes are not supported '
                    'for IntervalDtype')
             raise TypeError(msg)
@@ -994,7 +978,7 @@ def is_dtype(cls, dtype):
                         return True
                     else:
                         return False
-                except (ValueError, TypeError):
+                except ValueError:
                     return False
             else:
                 return False

From f2d2390f4817bda01ac5884ba74595f8c907c37e Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Mon, 18 Feb 2019 18:47:36 -0500
Subject: [PATCH 14/33] logic for string constructor and error message content
 updated

---
 pandas/core/dtypes/dtypes.py | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index 640d43f3b0e03..18614e8dde82c 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -931,10 +931,15 @@ def construct_from_string(cls, string):
         attempt to construct this type from a string, raise a TypeError
         if its not possible
         """
-        if (isinstance(string, compat.string_types) and
-            (string.startswith('interval') or
-             string.startswith('Interval'))):
-            return cls(string)
+        if isinstance(string, compat.string_types):
+            if (string.lower() == 'interval' or 
+                cls._match.search(string) is not None):
+                return cls(string)
+            else:
+                msg = ("Incorrectly formatted string passed to constructor. "
+                       "Valid formats include 'Interval' or 'Inverval[dtype]' "
+                       "where dtype is numeric, datetime, or timedelta")
+                raise TypeError(msg)
 
         msg = "a string needs to be passed, got type {typ}"
         raise TypeError(msg.format(typ=type(string)))

From 08ea833fd9bd75acdb376a6ab70c4e9c2e7890da Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Mon, 18 Feb 2019 18:52:32 -0500
Subject: [PATCH 15/33] construction error for IntervalA parameter moved to
 proper test

---
 pandas/tests/dtypes/test_dtypes.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/pandas/tests/dtypes/test_dtypes.py b/pandas/tests/dtypes/test_dtypes.py
index 00911a34a1672..43be93900d1df 100644
--- a/pandas/tests/dtypes/test_dtypes.py
+++ b/pandas/tests/dtypes/test_dtypes.py
@@ -503,8 +503,7 @@ def test_construction_generic(self, subtype):
     @pytest.mark.parametrize('subtype', [
         CategoricalDtype(list('abc'), False),
         CategoricalDtype(list('wxyz'), True),
-        object, str, '<U10', 'interval[category]', 'interval[object]',
-        'IntervalA'])
+        object, str, '<U10', 'interval[category]', 'interval[object]'])
     def test_construction_not_supported(self, subtype):
         # GH 19016
         msg = ('category, object, and string subtypes are not supported '
@@ -512,10 +511,11 @@ def test_construction_not_supported(self, subtype):
         with pytest.raises(TypeError, match=msg):
             IntervalDtype(subtype)
 
+    @pytest.mark.parametrize('subtype', ['xx', 'IntervalA'])
     def test_construction_errors(self):
         msg = 'could not construct IntervalDtype'
         with pytest.raises(TypeError, match=msg):
-            IntervalDtype('xx')
+            IntervalDtype(subtype)
 
     def test_construction_from_string(self):
         result = IntervalDtype('interval[int64]')

From 1a5fc1b77144d86aca33ee151c89110113824086 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Mon, 18 Feb 2019 18:57:11 -0500
Subject: [PATCH 16/33] IntervalDtype construct_from_string tests updated to
 separate a bad datatype (not a string) being passed, from a bad string being
 passed

---
 pandas/tests/dtypes/test_dtypes.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/pandas/tests/dtypes/test_dtypes.py b/pandas/tests/dtypes/test_dtypes.py
index 43be93900d1df..b701d48152009 100644
--- a/pandas/tests/dtypes/test_dtypes.py
+++ b/pandas/tests/dtypes/test_dtypes.py
@@ -524,7 +524,7 @@ def test_construction_from_string(self):
         assert is_dtype_equal(self.dtype, result)
 
     @pytest.mark.parametrize('string', [
-        'foo', 'foo[int64]', 0, 3.14, ('a', 'b'), None])
+        0, 3.14, ('a', 'b'), None])
     def test_construction_from_string_errors(self, string):
         # these are invalid entirely
         msg = 'a string needs to be passed, got type'
@@ -533,11 +533,12 @@ def test_construction_from_string_errors(self, string):
             IntervalDtype.construct_from_string(string)
 
     @pytest.mark.parametrize('string', [
-        'interval[foo]', 'IntervalA'])
+        'interval[foo]', 'IntervalA', 'foo', 'foo[int64]'])
     def test_construction_from_string_error_subtype(self, string):
         # this is an invalid subtype
-        msg = ('category, object, and string subtypes are not supported '
-               'for IntervalDtype')
+        msg = ("Incorrectly formatted string passed to constructor. "
+                "Valid formats include 'Interval' or 'Inverval[dtype]' "
+                "where dtype is numeric, datetime, or timedelta")
 
         with pytest.raises(TypeError, match=msg):
             IntervalDtype.construct_from_string(string)

From f2a3bdba3304e7f249afde712b3e38805572a3f4 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Mon, 18 Feb 2019 18:59:09 -0500
Subject: [PATCH 17/33] TypeError added to is_dtype exceptions, reflecting
 changes in the construct_from_string method

---
 pandas/core/dtypes/dtypes.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index 18614e8dde82c..ce19196c1657d 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -983,7 +983,7 @@ def is_dtype(cls, dtype):
                         return True
                     else:
                         return False
-                except ValueError:
+                except (ValueError, TypeError):
                     return False
             else:
                 return False

From 0011a8093e62878b90e85a548c219800cbf47ea6 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Mon, 18 Feb 2019 19:05:28 -0500
Subject: [PATCH 18/33] formatting fixes and test update

---
 pandas/core/dtypes/dtypes.py       | 2 +-
 pandas/tests/dtypes/test_dtypes.py | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index ce19196c1657d..6e9b78e21aeea 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -932,7 +932,7 @@ def construct_from_string(cls, string):
         if its not possible
         """
         if isinstance(string, compat.string_types):
-            if (string.lower() == 'interval' or 
+            if (string.lower() == 'interval' or
                 cls._match.search(string) is not None):
                 return cls(string)
             else:
diff --git a/pandas/tests/dtypes/test_dtypes.py b/pandas/tests/dtypes/test_dtypes.py
index b701d48152009..5c2dbda7058ea 100644
--- a/pandas/tests/dtypes/test_dtypes.py
+++ b/pandas/tests/dtypes/test_dtypes.py
@@ -512,7 +512,7 @@ def test_construction_not_supported(self, subtype):
             IntervalDtype(subtype)
 
     @pytest.mark.parametrize('subtype', ['xx', 'IntervalA'])
-    def test_construction_errors(self):
+    def test_construction_errors(self, subtype):
         msg = 'could not construct IntervalDtype'
         with pytest.raises(TypeError, match=msg):
             IntervalDtype(subtype)

From aa581fa4996a5c7aab0ba9459ea0b285f139be11 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Mon, 18 Feb 2019 19:06:39 -0500
Subject: [PATCH 19/33] formatting update

---
 pandas/core/dtypes/dtypes.py       | 2 +-
 pandas/tests/dtypes/test_dtypes.py | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index 6e9b78e21aeea..70d1d93e12191 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -934,7 +934,7 @@ def construct_from_string(cls, string):
         if isinstance(string, compat.string_types):
             if (string.lower() == 'interval' or
                 cls._match.search(string) is not None):
-                return cls(string)
+                    return cls(string)
             else:
                 msg = ("Incorrectly formatted string passed to constructor. "
                        "Valid formats include 'Interval' or 'Inverval[dtype]' "
diff --git a/pandas/tests/dtypes/test_dtypes.py b/pandas/tests/dtypes/test_dtypes.py
index 5c2dbda7058ea..a6d383d4f67c1 100644
--- a/pandas/tests/dtypes/test_dtypes.py
+++ b/pandas/tests/dtypes/test_dtypes.py
@@ -537,8 +537,8 @@ def test_construction_from_string_errors(self, string):
     def test_construction_from_string_error_subtype(self, string):
         # this is an invalid subtype
         msg = ("Incorrectly formatted string passed to constructor. "
-                "Valid formats include 'Interval' or 'Inverval[dtype]' "
-                "where dtype is numeric, datetime, or timedelta")
+               "Valid formats include 'Interval' or 'Inverval[dtype]' "
+               "where dtype is numeric, datetime, or timedelta")
 
         with pytest.raises(TypeError, match=msg):
             IntervalDtype.construct_from_string(string)

From 54bcf76e5922fe19c27dbb743161b80e56d233ef Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Mon, 18 Feb 2019 20:12:45 -0500
Subject: [PATCH 20/33] construct from string formatting fixes

---
 pandas/core/dtypes/dtypes.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index 70d1d93e12191..abf98b1740c34 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -933,7 +933,7 @@ def construct_from_string(cls, string):
         """
         if isinstance(string, compat.string_types):
             if (string.lower() == 'interval' or
-                cls._match.search(string) is not None):
+               cls._match.search(string) is not None):
                     return cls(string)
             else:
                 msg = ("Incorrectly formatted string passed to constructor. "

From 36f8571bfea9f4f2dc1d9aa01ce68d631552e867 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Mon, 18 Feb 2019 20:16:43 -0500
Subject: [PATCH 21/33] interval[foo] construct from string error moved to
 proper test category

---
 pandas/tests/dtypes/test_dtypes.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/tests/dtypes/test_dtypes.py b/pandas/tests/dtypes/test_dtypes.py
index a6d383d4f67c1..0ac077ce49ccd 100644
--- a/pandas/tests/dtypes/test_dtypes.py
+++ b/pandas/tests/dtypes/test_dtypes.py
@@ -511,7 +511,7 @@ def test_construction_not_supported(self, subtype):
         with pytest.raises(TypeError, match=msg):
             IntervalDtype(subtype)
 
-    @pytest.mark.parametrize('subtype', ['xx', 'IntervalA'])
+    @pytest.mark.parametrize('subtype', ['xx', 'IntervalA', 'Interval[foo]'])
     def test_construction_errors(self, subtype):
         msg = 'could not construct IntervalDtype'
         with pytest.raises(TypeError, match=msg):
@@ -533,7 +533,7 @@ def test_construction_from_string_errors(self, string):
             IntervalDtype.construct_from_string(string)
 
     @pytest.mark.parametrize('string', [
-        'interval[foo]', 'IntervalA', 'foo', 'foo[int64]'])
+        'IntervalA', 'foo', 'foo[int64]'])
     def test_construction_from_string_error_subtype(self, string):
         # this is an invalid subtype
         msg = ("Incorrectly formatted string passed to constructor. "

From 6e6fe2366128cbb7ba67974dd31080ca00a93d0f Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Mon, 18 Feb 2019 20:17:59 -0500
Subject: [PATCH 22/33] IntervalA construct from string error moved to proper
 test category

---
 pandas/tests/dtypes/test_dtypes.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/tests/dtypes/test_dtypes.py b/pandas/tests/dtypes/test_dtypes.py
index 0ac077ce49ccd..3b56b1c677e3d 100644
--- a/pandas/tests/dtypes/test_dtypes.py
+++ b/pandas/tests/dtypes/test_dtypes.py
@@ -533,7 +533,7 @@ def test_construction_from_string_errors(self, string):
             IntervalDtype.construct_from_string(string)
 
     @pytest.mark.parametrize('string', [
-        'IntervalA', 'foo', 'foo[int64]'])
+        'foo', 'foo[int64]'])
     def test_construction_from_string_error_subtype(self, string):
         # this is an invalid subtype
         msg = ("Incorrectly formatted string passed to constructor. "

From 5547b5fa0c68a71c213003ed84e17cfaf0481ab2 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Mon, 18 Feb 2019 21:06:53 -0500
Subject: [PATCH 23/33] IntervalDtype construct from string test error message
 handling updated, regex match in error message string was causing test to
 fail

---
 pandas/core/dtypes/dtypes.py       | 6 +++---
 pandas/tests/dtypes/test_dtypes.py | 9 +++++----
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index abf98b1740c34..e78a543d7faa7 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -936,9 +936,9 @@ def construct_from_string(cls, string):
                cls._match.search(string) is not None):
                     return cls(string)
             else:
-                msg = ("Incorrectly formatted string passed to constructor. "
-                       "Valid formats include 'Interval' or 'Inverval[dtype]' "
-                       "where dtype is numeric, datetime, or timedelta")
+                msg = ('Incorrectly formatted string passed to constructor. '
+                       'Valid formats include Interval or Inverval[dtype] '
+                       'where dtype is numeric, datetime, or timedelta')
                 raise TypeError(msg)
 
         msg = "a string needs to be passed, got type {typ}"
diff --git a/pandas/tests/dtypes/test_dtypes.py b/pandas/tests/dtypes/test_dtypes.py
index 3b56b1c677e3d..826f7ae26a797 100644
--- a/pandas/tests/dtypes/test_dtypes.py
+++ b/pandas/tests/dtypes/test_dtypes.py
@@ -536,12 +536,13 @@ def test_construction_from_string_errors(self, string):
         'foo', 'foo[int64]'])
     def test_construction_from_string_error_subtype(self, string):
         # this is an invalid subtype
-        msg = ("Incorrectly formatted string passed to constructor. "
-               "Valid formats include 'Interval' or 'Inverval[dtype]' "
-               "where dtype is numeric, datetime, or timedelta")
+        msg = ('Incorrectly formatted string passed to constructor. '
+               'Valid formats include Interval or Inverval[dtype] '
+               'where dtype is numeric, datetime, or timedelta')
 
-        with pytest.raises(TypeError, match=msg):
+        with pytest.raises(TypeError) as e:
             IntervalDtype.construct_from_string(string)
+            assert e == msg
 
     def test_subclass(self):
         a = IntervalDtype('interval[int64]')

From aedc7cca6e71fc8bbf4d99249ee46027c3654934 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Tue, 19 Feb 2019 08:17:56 -0500
Subject: [PATCH 24/33] re-ordering of logic in construct from string method
 for cleaner code

---
 pandas/core/dtypes/dtypes.py | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index e78a543d7faa7..3c64b5e0e2119 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -931,18 +931,18 @@ def construct_from_string(cls, string):
         attempt to construct this type from a string, raise a TypeError
         if its not possible
         """
-        if isinstance(string, compat.string_types):
-            if (string.lower() == 'interval' or
-               cls._match.search(string) is not None):
-                    return cls(string)
-            else:
-                msg = ('Incorrectly formatted string passed to constructor. '
-                       'Valid formats include Interval or Inverval[dtype] '
-                       'where dtype is numeric, datetime, or timedelta')
-                raise TypeError(msg)
-
-        msg = "a string needs to be passed, got type {typ}"
-        raise TypeError(msg.format(typ=type(string)))
+        if not isinstance(string, compat.string_types):
+            msg = "a string needs to be passed, got type {typ}"
+            raise TypeError(msg.format(typ=type(string)))
+
+        if (string.lower() == 'interval' or
+           cls._match.search(string) is not None):
+                return cls(string)
+
+        msg = ('Incorrectly formatted string passed to constructor. '
+               'Valid formats include Interval or Inverval[dtype] '
+               'where dtype is numeric, datetime, or timedelta')
+        raise TypeError(msg)
 
     @property
     def type(self):

From 2deba07d6ac0c1088275db1ac711ee19d0bd6dfb Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Tue, 19 Feb 2019 09:18:27 -0500
Subject: [PATCH 25/33] message string altered to work with regex matching

---
 pandas/tests/dtypes/test_dtypes.py | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/pandas/tests/dtypes/test_dtypes.py b/pandas/tests/dtypes/test_dtypes.py
index 826f7ae26a797..ff7c38cbce5d1 100644
--- a/pandas/tests/dtypes/test_dtypes.py
+++ b/pandas/tests/dtypes/test_dtypes.py
@@ -536,13 +536,12 @@ def test_construction_from_string_errors(self, string):
         'foo', 'foo[int64]'])
     def test_construction_from_string_error_subtype(self, string):
         # this is an invalid subtype
-        msg = ('Incorrectly formatted string passed to constructor. '
-               'Valid formats include Interval or Inverval[dtype] '
-               'where dtype is numeric, datetime, or timedelta')
+        msg = (r"""Incorrectly formatted string passed to constructor.
+               Valid formats include Interval or Inverval\[ dtype\]
+               where dtype is numeric, datetime, or timedelta""")
 
-        with pytest.raises(TypeError) as e:
+        with pytest.raises(TypeError, match=msg):
             IntervalDtype.construct_from_string(string)
-            assert e == msg
 
     def test_subclass(self):
         a = IntervalDtype('interval[int64]')

From c107ccdf5becb26e8131f3ce0c46bcf9a3965db9 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Tue, 19 Feb 2019 09:31:29 -0500
Subject: [PATCH 26/33] IntervalA test re-added to construct from string
 testing

---
 pandas/tests/dtypes/test_dtypes.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/pandas/tests/dtypes/test_dtypes.py b/pandas/tests/dtypes/test_dtypes.py
index ff7c38cbce5d1..78753ce45f607 100644
--- a/pandas/tests/dtypes/test_dtypes.py
+++ b/pandas/tests/dtypes/test_dtypes.py
@@ -533,12 +533,12 @@ def test_construction_from_string_errors(self, string):
             IntervalDtype.construct_from_string(string)
 
     @pytest.mark.parametrize('string', [
-        'foo', 'foo[int64]'])
+        'foo', 'foo[int64]', 'IntervalA'])
     def test_construction_from_string_error_subtype(self, string):
         # this is an invalid subtype
-        msg = (r"""Incorrectly formatted string passed to constructor.
-               Valid formats include Interval or Inverval\[ dtype\]
-               where dtype is numeric, datetime, or timedelta""")
+        msg = ("Incorrectly formatted string passed to constructor. "
+               "Valid formats include Interval or Inverval\[dtype\] "
+               "where dtype is numeric, datetime, or timedelta")
 
         with pytest.raises(TypeError, match=msg):
             IntervalDtype.construct_from_string(string)

From 989942e3148bf9963091ef0153e6be1dcb8f5559 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Tue, 19 Feb 2019 11:04:33 -0500
Subject: [PATCH 27/33] error message formatting fix for PEP8

---
 pandas/tests/dtypes/test_dtypes.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/tests/dtypes/test_dtypes.py b/pandas/tests/dtypes/test_dtypes.py
index 78753ce45f607..22a831687be53 100644
--- a/pandas/tests/dtypes/test_dtypes.py
+++ b/pandas/tests/dtypes/test_dtypes.py
@@ -537,7 +537,7 @@ def test_construction_from_string_errors(self, string):
     def test_construction_from_string_error_subtype(self, string):
         # this is an invalid subtype
         msg = ("Incorrectly formatted string passed to constructor. "
-               "Valid formats include Interval or Inverval\[dtype\] "
+               r"Valid formats include Interval or Inverval\[dtype\] "
                "where dtype is numeric, datetime, or timedelta")
 
         with pytest.raises(TypeError, match=msg):

From d28a0fd760de6064be9d9133cdfcaf4ae3551e38 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Tue, 19 Feb 2019 14:16:21 -0500
Subject: [PATCH 28/33] test added for comparing series with strings containing
 Interval keyword

---
 pandas/tests/series/test_operators.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pandas/tests/series/test_operators.py b/pandas/tests/series/test_operators.py
index 4d3c9926fc5ae..f8ec095c84b63 100644
--- a/pandas/tests/series/test_operators.py
+++ b/pandas/tests/series/test_operators.py
@@ -563,6 +563,10 @@ def test_comp_ops_df_compat(self):
             with pytest.raises(ValueError, match=msg):
                 left.to_frame() < right.to_frame()
 
+    def test_compare_series_interval_keyword(self):
+        s = Series(['IntervalA', 'IntervalB', 'IntervalC']) == 'IntervalA'
+        assert_series_equal(s, Series([True, False, False]))
+
 
 class TestSeriesFlexComparisonOps(object):
 

From e72bfb92a32d0508c87b46f5f7da56f157af4ff5 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Tue, 19 Feb 2019 14:20:14 -0500
Subject: [PATCH 29/33] regression fix documented in whats new for v0.24.2

---
 doc/source/whatsnew/v0.24.2.rst | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/doc/source/whatsnew/v0.24.2.rst b/doc/source/whatsnew/v0.24.2.rst
index 8e59c2300e7ca..45db1e1d5ada0 100644
--- a/doc/source/whatsnew/v0.24.2.rst
+++ b/doc/source/whatsnew/v0.24.2.rst
@@ -27,6 +27,8 @@ Fixed Regressions
 - Fixed regression in :meth:`DataFrame.duplicated()`, where empty dataframe was not returning a boolean dtyped Series. (:issue:`25184`)
 - Fixed regression in :meth:`Series.min` and :meth:`Series.max` where ``numeric_only=True`` was ignored when the ``Series`` contained ```Categorical`` data (:issue:`25299`)
 
+- Fixed regression in ``IntervalDtype`` construction passing in an approximately correct string could result in RecursionError. (:issue:`25338`)
+
 .. _whatsnew_0242.enhancements:
 
 Enhancements

From dfe6e99cafabf18bbba72c6589675ccf46fd15e2 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Tue, 19 Feb 2019 15:51:46 -0500
Subject: [PATCH 30/33] typo fix in construct_from_string error message

---
 pandas/core/dtypes/dtypes.py       | 2 +-
 pandas/tests/dtypes/test_dtypes.py | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index 3c64b5e0e2119..b5b762c5aecf4 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -940,7 +940,7 @@ def construct_from_string(cls, string):
                 return cls(string)
 
         msg = ('Incorrectly formatted string passed to constructor. '
-               'Valid formats include Interval or Inverval[dtype] '
+               'Valid formats include Interval or Intverval[dtype] '
                'where dtype is numeric, datetime, or timedelta')
         raise TypeError(msg)
 
diff --git a/pandas/tests/dtypes/test_dtypes.py b/pandas/tests/dtypes/test_dtypes.py
index 22a831687be53..c612c5caa984a 100644
--- a/pandas/tests/dtypes/test_dtypes.py
+++ b/pandas/tests/dtypes/test_dtypes.py
@@ -537,7 +537,7 @@ def test_construction_from_string_errors(self, string):
     def test_construction_from_string_error_subtype(self, string):
         # this is an invalid subtype
         msg = ("Incorrectly formatted string passed to constructor. "
-               r"Valid formats include Interval or Inverval\[dtype\] "
+               r"Valid formats include Interval or Intverval\[dtype\] "
                "where dtype is numeric, datetime, or timedelta")
 
         with pytest.raises(TypeError, match=msg):

From f08915f7963dc149db625b1989a130f483d11f28 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Tue, 19 Feb 2019 15:53:06 -0500
Subject: [PATCH 31/33] typo fix in construct_from_string error message

---
 pandas/core/dtypes/dtypes.py       | 2 +-
 pandas/tests/dtypes/test_dtypes.py | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/dtypes/dtypes.py b/pandas/core/dtypes/dtypes.py
index b5b762c5aecf4..11a132c4d14ee 100644
--- a/pandas/core/dtypes/dtypes.py
+++ b/pandas/core/dtypes/dtypes.py
@@ -940,7 +940,7 @@ def construct_from_string(cls, string):
                 return cls(string)
 
         msg = ('Incorrectly formatted string passed to constructor. '
-               'Valid formats include Interval or Intverval[dtype] '
+               'Valid formats include Interval or Interval[dtype] '
                'where dtype is numeric, datetime, or timedelta')
         raise TypeError(msg)
 
diff --git a/pandas/tests/dtypes/test_dtypes.py b/pandas/tests/dtypes/test_dtypes.py
index c612c5caa984a..1c1442d6f2f23 100644
--- a/pandas/tests/dtypes/test_dtypes.py
+++ b/pandas/tests/dtypes/test_dtypes.py
@@ -537,7 +537,7 @@ def test_construction_from_string_errors(self, string):
     def test_construction_from_string_error_subtype(self, string):
         # this is an invalid subtype
         msg = ("Incorrectly formatted string passed to constructor. "
-               r"Valid formats include Interval or Intverval\[dtype\] "
+               r"Valid formats include Interval or Interval\[dtype\] "
                "where dtype is numeric, datetime, or timedelta")
 
         with pytest.raises(TypeError, match=msg):

From f1fabdfd56aeef22e95fe1accad76a90edcbb614 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Tue, 19 Feb 2019 21:43:30 -0500
Subject: [PATCH 32/33] whatsnew note adjusted for clarity and style

---
 doc/source/whatsnew/v0.24.2.rst | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/doc/source/whatsnew/v0.24.2.rst b/doc/source/whatsnew/v0.24.2.rst
index 45db1e1d5ada0..f528c058d2868 100644
--- a/doc/source/whatsnew/v0.24.2.rst
+++ b/doc/source/whatsnew/v0.24.2.rst
@@ -26,8 +26,7 @@ Fixed Regressions
 
 - Fixed regression in :meth:`DataFrame.duplicated()`, where empty dataframe was not returning a boolean dtyped Series. (:issue:`25184`)
 - Fixed regression in :meth:`Series.min` and :meth:`Series.max` where ``numeric_only=True`` was ignored when the ``Series`` contained ```Categorical`` data (:issue:`25299`)
-
-- Fixed regression in ``IntervalDtype`` construction passing in an approximately correct string could result in RecursionError. (:issue:`25338`)
+- Fixed regression in ``IntervalDtype`` construction where passing an incorrect string with 'Interval' as a prefix could result in a ``RecursionError``. (:issue:`25338`)
 
 .. _whatsnew_0242.enhancements:
 

From 1ed7f8cc474923296d545fda94e61c8226d3fac9 Mon Sep 17 00:00:00 2001
From: zangell44 <42625717+zangell44@users.noreply.github.com>
Date: Tue, 19 Feb 2019 21:46:24 -0500
Subject: [PATCH 33/33] formatting update for
 test_compare_series_interval_keyword

---
 pandas/tests/series/test_operators.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/pandas/tests/series/test_operators.py b/pandas/tests/series/test_operators.py
index f8ec095c84b63..b2aac441db195 100644
--- a/pandas/tests/series/test_operators.py
+++ b/pandas/tests/series/test_operators.py
@@ -564,8 +564,11 @@ def test_comp_ops_df_compat(self):
                 left.to_frame() < right.to_frame()
 
     def test_compare_series_interval_keyword(self):
-        s = Series(['IntervalA', 'IntervalB', 'IntervalC']) == 'IntervalA'
-        assert_series_equal(s, Series([True, False, False]))
+        # GH 25338
+        s = Series(['IntervalA', 'IntervalB', 'IntervalC'])
+        result = s == 'IntervalA'
+        expected = Series([True, False, False])
+        assert_series_equal(result, expected)
 
 
 class TestSeriesFlexComparisonOps(object):