[peter-targett]

Summary

Fix schema upgrades re-applying the upgrade to the current version (98b8dee)

Upgrade functions are registered against the version they upgrade to, but
_instance_from_schema also ran the upgrade for the version the object was already at
(schema_version <= e.first).

Upgrades now only apply to versions above the object's own. Also corrected
test_upgrade_versions, which fed version 2 data labelled as version 3 and so
encoded the old behaviour.

Allow bundles to be written at older schema versions (c866e70)

Add bundle::WriteOptions::target_schema_versions, which is passed through to the
JSON writer - this lets an .otiod/.otioz be written for an older OTIO to read,
e.g. "0.18.1" versions, which have Marker.2.

The otiod and otioz adapters take a matching target_schema_versions argument. Like
otio_json, they fall back to OTIO_DEFAULT_TARGET_VERSION_FAMILY_LABEL when it
isn't given, so otioconvert can downgrade bundles too:

  otioconvert -i in.otio -o out.otioz -A target_schema_versions="{'Marker':2}"

Documentation

• otio-filebundles.md: new "target_schema_versions Optional Argument" section
• versioning-schemas.md: the env var and otioconvert sections now cover bundles, plus the
  C++ option
• otio-plugins.md: regenerated for the new adapter argument

Testing

• tests/test_marker.py: reads a genuine Marker.2 file
• tests/test_serializable_object.py: corrected upgrade test
• tests/test_otiod.py: writes a bundle via otio.adapters.write_to_file with
  target_schema_versions, and via the env var fallback
• tests/test_otioz.py: same for .otioz, checking content.otio inside the zip
• Manually checked the otioconvert example above: the bundle's content.otio contains
  Marker.2

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.67%. Comparing base (80c5ff3) to head (aee5715).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2084      +/-   ##
==========================================
+ Coverage   83.59%   83.67%   +0.08%     
==========================================
  Files         184      184              
  Lines       13632    13691      +59     
  Branches     1271     1273       +2     
==========================================
+ Hits        11395    11456      +61     
+ Misses       2064     2063       -1     
+ Partials      173      172       -1     

Flag	Coverage Δ
py-unittests	83.67% <100.00%> (+0.08%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/opentimelineio/bundle.cpp	49.44% <100.00%> (+0.22%)	⬆️
src/opentimelineio/typeRegistry.cpp	83.15% <100.00%> (ø)
...timelineio/opentimelineio-bindings/otio_bundle.cpp	69.56% <100.00%> (+0.67%)	⬆️
...py-opentimelineio/opentimelineio/adapters/otiod.py	89.47% <100.00%> (+3.75%)	⬆️
...py-opentimelineio/opentimelineio/adapters/otioz.py	80.00% <100.00%> (+6.66%)	⬆️
tests/test_marker.py	97.33% <100.00%> (+0.19%)	⬆️
tests/test_otiod.py	96.42% <100.00%> (+1.83%)	⬆️
tests/test_otioz.py	95.55% <100.00%> (+4.25%)	⬆️
tests/test_serializable_object.py	93.37% <100.00%> (ø)

... and 1 file with indirect coverage changes

---

Continue to review full report in Codecov by Harness.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 80c5ff3...aee5715. Read the comment docs.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.