Deprecate colcon_mixin.mixin.repository.mixin_repositories_file

[cottsay]

Importing this module currently requires that colcon has already initialized the config location, which makes testing difficult and produces undesired behavior if the location changes during runtime. Following the behavior of colcon_mixin.mixin.get_mixin_path, we should use a "getter" pattern here.

This change also adds a test for an existing deprecation in this package.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 69.23077% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 15.30%. Comparing base (c91a0fd) to head (d581a36).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
colcon_mixin/mixin/repository.py	69.23%	3 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           master      #55       +/-   ##
===========================================
+ Coverage    0.00%   15.30%   +15.30%     
===========================================
  Files          11       11               
  Lines         551      562       +11     
  Branches        0       94       +94     
===========================================
+ Hits            0       86       +86     
+ Misses        551      474       -77     
- Partials        0        2        +2     

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[leander-dsouza]

Added some minor comments about the category of warning to be raised.

However, importing set_repositories on its own still leads to an error, as set_default_config_path needs to be called before get_config_path().

[leander-dsouza]

Suggested change

	"get_mixin_repositories_file()' instead", stacklevel=2)
	"get_mixin_repositories_file()' instead",
	DeprecationWarning, stacklevel=2)

PEP 387 suggests adding DeprecationWarning as the warning category for usage.

In anticipation of this change, I have added suggestions to the tests to match this call.

[cottsay]

This package already uses UserWarning for deprecations elsewhere. The main reason is that DeprecationWarning messages are not shown to on the console and are effectively silent unless specifically enabled: https://docs.python.org/3/library/warnings.html#default-warning-filter

[leander-dsouza]

Thank you for the explanation, Scott. The remaining associated comments are related to this addition and can therefore be ignored.