TST/DOC/BUG: Accommodate OpenPyXL incompatibility

* Detect whether a compatible version is installed * Skip openpyxl unit tests instead of failing * Inhibit registration of `openpyxl` engine in `ExcelWriter` * Raise `UserWarning` * Document limitation as a known issue * Resolve issue #7169

Author: neirbowj

README.md

@@ -114,7 +114,8 @@ pip install pandas
  - [xlrd/xlwt](http://www.python-excel.org/)
  - Excel reading (xlrd) and writing (xlwt)
  - [openpyxl](http://packages.python.org/openpyxl/)
- - openpyxl version 1.6.1 or higher, for writing .xlsx files
+ - openpyxl version 1.6.1 or higher, but lower than 2.0.0, for
+ writing .xlsx files
  - xlrd >= 0.9.0
  - [XlsxWriter](https://pypi.python.org/pypi/XlsxWriter)
  - Alternative Excel writer.

doc/source/install.rst

@@ -97,7 +97,7 @@ Optional Dependencies
  * `statsmodels <http://statsmodels.sourceforge.net/>`__
  * Needed for parts of :mod:`pandas.stats`
  * `openpyxl <http://packages.python.org/openpyxl/>`__, `xlrd/xlwt <http://www.python-excel.org/>`__
- * openpyxl version 1.6.1 or higher
+ * openpyxl version 1.6.1 or higher, but lower than 2.0.0
  * Needed for Excel I/O
  * `XlsxWriter <https://pypi.python.org/pypi/XlsxWriter>`__
  * Alternative Excel writer.

doc/source/v0.14.0.txt

@@ -31,6 +31,8 @@ users upgrade to this version.
 
 - :ref:`Deprecations <whatsnew_0140.deprecations>`
 
+- :ref:`Known Issues <whatsnew_0140.knownissues>`
+
 - :ref:`Bug Fixes <release.bug_fixes-0.14.0>`
 
 .. warning::
@@ -630,6 +632,14 @@ Deprecations
  in a future release. You can use the future behavior now by passing ``return_type='axes'``
  to boxplot.
 
+.. _whatsnew_0140.knownissues:
+
+Known Issues
+~~~~~~~~~~~~
+
+- OpenPyXL 2.0.0 breaks backwards compatibility (:issue:`7196`)
+
+
 .. _whatsnew_0140.enhancements:
 
 Enhancements

pandas/compat/openpyxl_compat.py

@@ -0,0 +1,26 @@
+"""
+Detect incompatible version of OpenPyXL
+
+GH7169
+"""
+
+from distutils.version import LooseVersion
+
+start_ver = '1.6.1'
+stop_ver = '2.0.0'
+
+def is_compat():
+ """
+ Detect whether the installed version of openpyxl is supported
+ Returns True/False if openpyxl is installed, None otherwise
+ """
+ try:
+ import openpyxl
+ except ImportError:
+ return None
+
+ ver = LooseVersion(openpyxl.__version__)
+ if ver < LooseVersion(start_ver) or LooseVersion(stop_ver) <= ver:
+ return False
+
+ return True

pandas/io/excel.py

@@ -16,6 +16,7 @@
 from pandas.core import config
 from pandas.core.common import pprint_thing
 import pandas.compat as compat
+import pandas.compat.openpyxl_compat as openpyxl_compat
 import pandas.core.common as com
 from warnings import warn
 from distutils.version import LooseVersion
@@ -617,7 +618,12 @@ def _convert_to_style(cls, style_dict):
 
  return xls_style
 
-register_writer(_OpenpyxlWriter)
+
+if openpyxl_compat.is_compat():
+ register_writer(_OpenpyxlWriter)
+else:
+ warn('Installed openpyxl is not supported at this time. Use >={} and <{}.'
+ .format(openpyxl_compat.start_ver, openpyxl_compat.stop_ver))
 
 
 class _XlwtWriter(ExcelWriter):

pandas/io/tests/test_excel.py

@@ -1,6 +1,6 @@
 # pylint: disable=E1101
 
-from pandas.compat import u, range, map
+from pandas.compat import u, range, map, openpyxl_compat
 from datetime import datetime, date, time
 import os
 from distutils.version import LooseVersion
@@ -45,6 +45,10 @@ def _skip_if_no_openpyxl():
  except ImportError:
  raise nose.SkipTest('openpyxl not installed, skipping')
 
+ if not openpyxl_compat.is_compat():
+ raise nose.SkipTest('need %s <= openpyxl < %s, skipping' %
+ (openpyxl_compat.start_ver, openpyxl_compat.stop_ver))
+
 
 def _skip_if_no_xlsxwriter():
  try: