> * tricks to inject hooks ASAP (e.g. coverage.py swaps the encodings module) may lose their entry point

FWIW, I asked Ned Batchelder about this and he said this approach ("fullcoverage" [1]) was added to support running coverage on the stdlib.  It doesn't affect other users of coverage.py.  He didn't have any info on where this is used currently, though I'm pretty sure we do run coverage in CI.  Furthermore, the devguide talks about running coverage.py on the stdlib and initially indicates that modules imported during startup are not covered. [2]  However, it does have a section talking about using "fullcoverage" to cover startup modules.

I expect that any solution we make for contributors editing stdlib source files will resolve the potential issue for coverage.py.


[1] https://github.com/nedbat/coveragepy/tree/master/coverage/fullcoverage
[2] https://devguide.python.org/coverage/?highlight=coverage#measuring-coverage
[3] https://devguide.python.org/coverage/?highlight=coverage#coverage-results-for-modules-imported-early-on