BUG: avoid usage in_qtconsole for recent IPython versions (pandas-dev#25039)

* Drop IPython<4.0 compat

* Revert "Drop IPython<4.0 compat"

This reverts commit 0cb0452.

* update
a
* whatsnew

Author: TomAugspurger

doc/source/whatsnew/v0.24.1.rst

@@ -83,7 +83,7 @@ Bug Fixes
 
 **Other**
 
--
+- Fixed AttributeError when printing a DataFrame's HTML repr after accessing the IPython config object (:issue:`25036`)
 -
 
 .. _whatsnew_0.241.contributors:

pandas/core/frame.py

@@ -17,6 +17,7 @@
 import itertools
 import sys
 import warnings
+from distutils.version import LooseVersion
 from textwrap import dedent
 
 import numpy as np
@@ -646,9 +647,15 @@ def _repr_html_(self):
         # XXX: In IPython 3.x and above, the Qt console will not attempt to
         # display HTML, so this check can be removed when support for
         # IPython 2.x is no longer needed.
-        if console.in_qtconsole():
-            # 'HTML output is disabled in QtConsole'
-            return None
+        try:
+            import IPython
+        except ImportError:
+            pass
+        else:
+            if LooseVersion(IPython.__version__) < LooseVersion('3.0'):
+                if console.in_qtconsole():
+                    # 'HTML output is disabled in QtConsole'
+                    return None
 
         if self._info_repr():
             buf = StringIO(u(""))

pandas/tests/io/formats/test_format.py

@@ -12,6 +12,7 @@
 import os
 import re
 import sys
+import textwrap
 import warnings
 
 import dateutil
@@ -2777,3 +2778,17 @@ def test_format_percentiles():
         fmt.format_percentiles([2, 0.1, 0.5])
     with pytest.raises(ValueError, match=msg):
         fmt.format_percentiles([0.1, 0.5, 'a'])
+
+
+def test_repr_html_ipython_config(ip):
+    code = textwrap.dedent("""\
+    import pandas as pd
+    df = pd.DataFrame({"A": [1, 2]})
+    df._repr_html_()
+
+    cfg = get_ipython().config
+    cfg['IPKernelApp']['parent_appname']
+    df._repr_html_()
+    """)
+    result = ip.run_cell(code)
+    assert not result.error_in_exec