PSA: how to deal with MANIFEST.json in web-platform-tests

[Philip Jägenstedt]

Anyone who's tried to make use of the new 2-way sync with web-platform-tests has probably noticed that MANIFEST.json is strange and annoying.

Unfortunately, it is worse than I realized before the "launch," as an update to the MANIFEST.json format in January now includes the hashes of all files. (That's to make incremental updates faster.) Even *-expected.txt and MANIFEST.json itself is included, and naturally changes every time the manifest is updated.

Somehow updating MANIFEST.json automatically (and getting it out of source control) is the highest priority issue for the 2-way sync process now, but in the meanwhile:

• Use the command in https://chromium.googlesource.com/chromium/src/+/master/docs/testing/web_platform_tests.md to update the manifest.
• It's easy to forget, and for example the auto-rebaseline bot doesn't update the manifest, so if there are other spurious-looking changes to MANIFEST.json, just commit those too.
• If you use git add -p, skip the hash change for MANIFEST.json, it serves no purpose and will probably conflict.
• Any two changes to the same file will inevitable cause a conflict on the hash line, so sigh a little bit, rebase and try again.

It is of course an option to just not use web-platform-tests until this has been resolved.

[Philip Jägenstedt]

FYI, this has now been resolved and the documentation is updated to the simplified workflow. Thanks Jeff and Quinten!

It's not unlikely that some further manifest-related problems will pop up, and whether it's that or something else, please complain loudly about any issues with the web-platform-tests workflow.