Enhance visibility of missing dependencies

[pnuu]

Curently PyYAML hides import errors in instantiated classes, and these are only logged at DEBUG level. This PR changes the log level to ERROR for these cases.

• Tests added

[pnuu]

This was the original log message when defusedxml was not installed for avhrr_l1b_eps reader. Note that the crucial info - missing defusedxml library - is reported in a DEBUG level message.

[DEBUG: 2024-10-16 11:01:28 : satpy.readers.yaml_reader] Reading ('/home/lahtinep/Software/pytroll/pytroll_packages/satpy/satpy/etc/readers/avhrr_l1b_eps.yaml',)
[INFO: 2024-10-16 11:01:28 : satpy.readers] Cannot use ['/home/lahtinep/Software/pytroll/pytroll_packages/satpy/satpy/etc/readers/avhrr_l1b_eps.yaml']
[DEBUG: 2024-10-16 11:01:28 : satpy.readers] while constructing a Python object
cannot find module 'satpy.readers.eps_l1b' (No module named 'defusedxml')
  in "/home/lahtinep/Software/pytroll/pytroll_packages/satpy/satpy/etc/readers/avhrr_l1b_eps.yaml", line 144, column 22
[WARNING: 2024-10-16 11:01:28 : satpy.readers] Don't know how to open the following files: {'/home/lahtinep/data/satellite/polar/avhrr_l1b_nat/AVHR_xxx_1B_M01_20241015100703Z_20241015114603Z_N_O_20241015105547Z.nat'}
Traceback (most recent call last):
  File "/home/lahtinep/bin/test_avhrr_l1b_nat.py", line 16, in <module>
    main()
  File "/home/lahtinep/bin/test_avhrr_l1b_nat.py", line 12, in main
    scn = Scene(reader="avhrr_l1b_eps", filenames=[fname])
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/lahtinep/Software/pytroll/pytroll_packages/satpy/satpy/scene.py", line 155, in __init__
    self._readers = self._create_reader_instances(filenames=filenames,
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/lahtinep/Software/pytroll/pytroll_packages/satpy/satpy/scene.py", line 176, in _create_reader_instances
    return load_readers(filenames=filenames,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/lahtinep/Software/pytroll/pytroll_packages/satpy/satpy/readers/__init__.py", line 590, in load_readers
    _check_reader_instances(reader_instances)
  File "/home/lahtinep/Software/pytroll/pytroll_packages/satpy/satpy/readers/__init__.py", line 629, in _check_reader_instances
    raise ValueError("No supported files found")
ValueError: No supported files found

[codecov]

Codecov Report

Attention: Patch coverage is 93.33333% with 3 lines in your changes missing coverage. Please review.

Project coverage is 96.08%. Comparing base (b8991c0) to head (3db6547).
Report is 112 commits behind head on main.

Files with missing lines	Patch %	Lines
satpy/readers/__init__.py	86.95%	3 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##             main    #2931    +/-   ##
========================================
  Coverage   96.07%   96.08%            
========================================
  Files         373      375     +2     
  Lines       54491    54612   +121     
========================================
+ Hits        52352    52472   +120     
- Misses       2139     2140     +1     

Flag	Coverage Δ
behaviourtests	3.98% <6.66%> (-0.01%)	⬇️
unittests	96.17% <93.33%> (+<0.01%)	⬆️

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[mraspaud]

Is there a more fine-grained exception we could catch instead, for just building objects (which probably mean a missing import)?

[pnuu]

I don't know. I'll have a look after figuring out the CodeScene complaint.

[coveralls]

Pull Request Test Coverage Report for Build 11366063321

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 42 of 45 (93.33%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.007%) to 96.177%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
satpy/readers/init.py	20	23	86.96%

Totals
Change from base Build 11324402105:	0.007%
Covered Lines:	52708
Relevant Lines:	54803

---

💛 - Coveralls

[pnuu]

ca987bc should make CodeScene happier. Later today I'll look if there are more fine-grained failures we could check for, but I have a feeling there is none as YAMLError was there also originally.

[mraspaud]

https:/yaml/pyyaml/blob/69c141adcf805c5ebdc9ba519927642ee5c7f639/lib/yaml/constructor.py#L552 -> ConstructorError?

[pnuu]

ConstructorError seems to work perfectly 👍

[mraspaud]

Thanks for working on this, just a couple of comments/questions