#144 Remove DeprecationWarning in Python >= 3.4

[Hugo]

Fixes https://sourceforge.net/p/docutils/bugs/348/.

Currently there's a DeprecationWarning when using Python >= 3.4:

/usr/local/lib/python3.7/site-packages/docutils/io.py:245: DeprecationWarning: 'U' mode is deprecated

The attached patch uses mode r for Python >= 3.4, otherwise rU:

mode = 'r' if sys.version_info >= (3, 4) else 'rU'

Tests pass locally for Python 2.7.15 and Python 3.7.0:

⌂71% [hugo:/tmp/docutils-code/docutils] trunk(1) ‡ python2 test/alltests.py
Testing Docutils 0.15b.dev with Python 2.7.15 on 2018-09-08 at 15:30:43
OS: Darwin 17.7.0 Darwin Kernel Version 17.7.0: Thu Jun 21 22:53:14 PDT 2018; root:xnu-4570.71.2~1/RELEASE_X86_64 (darwin, Darwin-17.7.0-x86_64-i386-64bit)
Working directory: /private/tmp/docutils-code/docutils/test
Docutils package: /private/tmp/docutils-code/docutils/docutils
............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
----------------------------------------------------------------------
Ran 1388 tests in 9.967s

OK
Elapsed time: 12.112 seconds
[hugo:/tmp/docutils-code/docutils] trunk(1) 12s ‡ python3 test3/alltests.py
Testing Docutils 0.15b.dev with Python 3.7.0 on 2018-09-08 at 15:31:06
OS: Darwin 17.7.0 Darwin Kernel Version 17.7.0: Thu Jun 21 22:53:14 PDT 2018; root:xnu-4570.71.2~1/RELEASE_X86_64 (darwin, Darwin-17.7.0-x86_64-i386-64bit)
Working directory: /private/tmp/docutils-code/docutils/test3
Docutils package: /private/tmp/docutils-code/docutils/build/lib/docutils
...............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
----------------------------------------------------------------------
Ran 1391 tests in 8.363s

OK
Elapsed time: 9.726 seconds

[engelbert gruber]

... and a test that fails before and passes after applying ... :-)

[Hugo]

Here's the patch with a test that fails on Python 3.7 before, and passes after.

Before:

⌂71% [hugo:/private/tmp/docutils-code/docutils] trunk(1) 14s ‡ python2 test/alltests.py && python3 setup.py build && python3 test3/alltests.py
Testing Docutils 0.15b.dev with Python 2.7.15 on 2018-09-09 at 13:40:54
OS: Darwin 17.7.0 Darwin Kernel Version 17.7.0: Thu Jun 21 22:53:14 PDT 2018; root:xnu-4570.71.2~1/RELEASE_X86_64 (darwin, Darwin-17.7.0-x86_64-i386-64bit)
Working directory: /private/tmp/docutils-code/docutils/test
Docutils package: /private/tmp/docutils-code/docutils/docutils
.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
----------------------------------------------------------------------
Ran 1389 tests in 10.110s

OK
Elapsed time: 12.251 seconds
running build
running build_py
build_py_2to3
copying docutils/io.py -> build/lib/docutils
Skipping optional fixer: buffer
Skipping optional fixer: idioms
Skipping optional fixer: set_literal
Skipping optional fixer: ws_comma
copy/convert test suite
running build_scripts
running build_data
Testing Docutils 0.15b.dev with Python 3.7.0 on 2018-09-09 at 13:41:07
OS: Darwin 17.7.0 Darwin Kernel Version 17.7.0: Thu Jun 21 22:53:14 PDT 2018; root:xnu-4570.71.2~1/RELEASE_X86_64 (darwin, Darwin-17.7.0-x86_64-i386-64bit)
Working directory: /private/tmp/docutils-code/docutils/test3
Docutils package: /private/tmp/docutils-code/docutils/build/lib/docutils
...................................................................................................................F............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
======================================================================
FAIL: test_deprecation_warning (test_io.InputTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/private/tmp/docutils-code/docutils/test3/test_io.py", line 149, in test_deprecation_warning
    list(v.category for v in w))
AssertionError: 1 != 0 : Expected no warnings, got [<class 'DeprecationWarning'>]

----------------------------------------------------------------------
Ran 1392 tests in 8.471s

FAILED (failures=1)
Elapsed time: 10.014 seconds

After:

⌂66% [hugo:/private/tmp/docutils-code/docutils] trunk(2) 23s 1 ‡ python2 test/alltests.py && python3 setup.py build && python3 test3/alltests.py
Testing Docutils 0.15b.dev with Python 2.7.15 on 2018-09-09 at 13:42:30
OS: Darwin 17.7.0 Darwin Kernel Version 17.7.0: Thu Jun 21 22:53:14 PDT 2018; root:xnu-4570.71.2~1/RELEASE_X86_64 (darwin, Darwin-17.7.0-x86_64-i386-64bit)
Working directory: /private/tmp/docutils-code/docutils/test
Docutils package: /private/tmp/docutils-code/docutils/docutils
.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
----------------------------------------------------------------------
Ran 1389 tests in 9.531s

OK
Elapsed time: 11.542 seconds
running build
running build_py
build_py_2to3
copying docutils/io.py -> build/lib/docutils
Skipping optional fixer: buffer
Skipping optional fixer: idioms
Skipping optional fixer: set_literal
Skipping optional fixer: ws_comma
copy/convert test suite
running build_scripts
running build_data
Testing Docutils 0.15b.dev with Python 3.7.0 on 2018-09-09 at 13:42:42
OS: Darwin 17.7.0 Darwin Kernel Version 17.7.0: Thu Jun 21 22:53:14 PDT 2018; root:xnu-4570.71.2~1/RELEASE_X86_64 (darwin, Darwin-17.7.0-x86_64-i386-64bit)
Working directory: /private/tmp/docutils-code/docutils/test3
Docutils package: /private/tmp/docutils-code/docutils/build/lib/docutils
................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
----------------------------------------------------------------------
Ran 1392 tests in 8.179s

OK
Elapsed time: 9.477 seconds

[Günter Milde]

Applied by grubert in [r8228]