Deprecation warnings not raised for SolutionArray methods

[ischoegl]

System information

• Cantera version: 2.5.0a3
• OS: Ubuntu 18.04
• Python/MATLAB version: 3.6.8

Expected behavior

All deprecation warnings are raised as expected.

Actual behavior

No deprecation warnings are displayed

To Reproduce

In [1]: import cantera as ct
   ...: gas = ct.Solution('gri30.yaml')
   ...: w = ct.Water()
   ...: w.TQ = 300., .5
   ...: a = ct.SolutionArray(gas, 10)
   ...: b = ct.SolutionArray(w, 2)
   ...: 

In [2]: b.TPX # <--- no warning issued, although method raising warning is called
Out[2]: 
(array([ 300.,  300.]), array([ 3528.21380229,  3528.21380229]), array([[ 0.5],
        [ 0.5]]))

In [3]: w.TPX # <--- calling the original method directly raises the warning
/usr/bin/ipython3:1: DeprecationWarning: To be removed after Cantera 2.5. Attribute renamed to 'TPQ'
  #! /bin/sh
Out[3]: (300.0, 3528.213802290444, 0.5000000000000002)

In [4]: b.TPQ # <--- new version, which treats Q as a scalar
Out[4]: 
(array([ 300.,  300.]),
 array([ 3528.21380229,  3528.21380229]),
 array([ 0.5,  0.5]))

Additional context

Behavior was first observed for #719; issue may be connected to #746

[speth]

Isn't this mostly a consequence of how DeprecationWarning is handled by default in Python? That is, ignored by default except (starting in Python 3.7) when issued directly from __main__? (see https://www.python.org/dev/peps/pep-0565/)

I'm actually more confused by the fact that the DeprecationWarning is shown for In [3]. Perhaps that is some weirdness related to Cython?

I think you should see the deprecation warning if you run warnings.simplefilter("default"). This is what is done in the test suite in runCythonTests.py (although there are unfortunately several tests that replace this without setting it back).

[ischoegl]

@speth ... warnings.simplefilter("default") indeed forces the warnings to be displayed for In [2]. But your other point remains ... taken together, the behavior is definitely not consistent.