In python-2.7 deprecation warnings are not shown to the user by default

[fbissey]

In python 2.7 deprecation warnings are a developer only feature. Which mean that sage's deprecation warnings are not shown either. A previous patch in #9958 only re-enable deprecation warnings in doctests but not in regular sage sessions.

Apply:

• trac_11244_reenable_deprecationwarnings_in_python27.patch
• trac_11244_fix_combinatpartition_warnings.patch
• trac_11244_fixmoredeprecationswarnings.2.patch

[fbissey]

new patch to restore deprecation warnings in python 2.7 (now in git format)

[fbissey]

There is an issue with

sage -t -force_lib "devel/sage-main/sage/combinat/partition.py"
**********************************************************************
File "/usr/share/sage/devel/sage-main/sage/combinat/partition.py", line 2511:
    sage: RestrictedPartitions(5,[3,2,1])
Expected:
    doctest:...: DeprecationWarning: RestrictedPartitions is deprecated; use Partitions with the parts_in keyword instead.
    doctest:...: DeprecationWarning: RestrictedPartitions_nsk is deprecated; use Partitions with the parts_in keyword instead.
    Partitions of 5 restricted to the values [1, 2, 3]
Got:
    doctest:260: DeprecationWarning: RestrictedPartitions_nsk is deprecated; use Partitions with the parts_in keyword instead.
    Partitions of 5 restricted to the values [1, 2, 3] 

But clearly I am not sure why the original code should give both a warning and a deprecation warning. Of course my patch only let sage display the later.

[fbissey]

The code in question

    import warnings
    warnings.warn('RestrictedPartitions is deprecated; use Partitions with the parts_in keyword instead.', DeprecationWarning, stacklevel=2)
    from sage.misc.misc import deprecation
    deprecation('RestrictedPartitions is deprecated; use Partitions with the parts_in keyword instead.')
    return RestrictedPartitions_nsk(n, S, k)

[fbissey]

I see that in fact there are are two related functions being deprecated and this is a way to warn for both at the same time.

[fbissey]

Patch to reenable extra deprecation warning in sage/combinat/partition.py.

[fbissey]

Fixing my mistaken assumptions about warnings in general.

[fbissey]

There are more deprecation warnings issued by the standard python mechanism rather than sage's mechanism

sage-4.7.alpha1 $ grep -r DeprecationWarning\,\ stacklevel *
sage/matrix/constructor.py:                    warnings.warn("invocation of block_matrix with just a list whose length is a perfect square is deprecated. See the documentation for details.", DeprecationWarning, stacklevel=2)
sage/combinat/partition.py:    warnings.warn('RestrictedPartitions is deprecated; use Partitions with the parts_in keyword instead.', DeprecationWarning, stacklevel=2)
sage/combinat/partition.py:        warnings.warn('RestrictedPartitions_nsk is deprecated; use Partitions with the parts_in keyword instead.', DeprecationWarning, stacklevel=2)
sage/groups/perm_gps/permgroup.py:        warnings.warn('quotient_group() is deprecated; use quotient() instead.', DeprecationWarning, stacklevel=2)
sage/graphs/base/graph_backends.py:                    DeprecationWarning, stacklevel=2)
sage/graphs/base/graph_backends.py:                    DeprecationWarning, stacklevel=2)
sage/misc/misc.py:    warn(message, DeprecationWarning, stacklevel=3)

[fbissey]

3 more files fixed. double messaging removed in two of them. [rebased on 4.7.alpha5]

[fbissey]

Use this patch if you base your review on 4.7.1.alpha1

[mariah]

Patches applied to sage-4.7.1.alpha2, then did 'sage -b', followed by 'make testlong'. All tests passed. Positive review!

[fbissey]

Thank you Mariah for the review. Thank you John for the suggestion to make it better. Thank you Steve for pointing the obvious.

Thank you all for making this reach this stage.

[fbissey]

Removing the work issue as it was in fact dealt with.

[jason]

(for another ticket) maybe it would be best if we subclassed the warnings to all inherit from a SageWarning? class, and then turn on just Sage warnings...