Diff wrapper does not show difference between 1.5 and 1.6

[KatieWoe]

Test device
Dell
Operating System
Win 11
Browser
Chrome
Problem description
For phetsims/qa#816.
In the diff wrapper for 1.6, entering the url for 1.5 shows no results and the console shows the errors shown bellow.

Visuals

[KatieWoe]

I got the same error when trying to compare 1.6 to itself.

[KatieWoe]

This also happens in Firefox

[samreid]

I think the user interface was changed so no you are supposed to type "1.5" in the textbox instead of a full URL. Can you please re-test it that way?

[KatieWoe]

That does seem to work for the old version. Typing 1.6 to try to compare it to itself does not work though.
I also see this in phetsims/qa#818

[zepumph]

We will investigate why we can't load 1.6 and compare it to 1.6.

[samreid]

If I recall correctly, yesterday @zepumph volunteered to check this part. If I misremember or if you want me to take the lead for any reason, please reassign me.

[samreid]

I believe this answer is straightforward. It is able to load prior versions because the API file for the prior versions is published on the phet-io website at a standard location. Since we are testing a dev or RC version for 1.6, there is no API file for the production version of 1.6 at the standard location, therefore the comparison cannot be made. I believe this is an acceptable and useful constraint that does not need to be documented because it will not impact our clients. Once we have published a production version of 1.6, I would expect it to be able to compare to itself. But we will not be able to test that until we publish a production version.

@zepumph OK to close? Or do you want a spot check after publication?

[zepumph]

Recent changes to the diff wrapper have caused us to not be able to just diff two arbitrary links. In my opinion that is a regression that was not necessary, and not that beneficial. I agree that this error is "acceptable" because it won't effect clients, but why would we set up our wrapper to not be able to diff against a version in an RC. It just seems like we are asking to have to do more work later.

[samreid]

Client.getAPIFile currently takes a version. Do you recommend that getAPIFile would take version|URL? Or two methods, like getAPIFileForVersion and getAPIFileForURL?

I also tried entering 1.6.0-dev.2 for the comparison and it said APIs are identical. Is that acceptable for now? Is this work blocking the upcoming release?

[samreid]

@zepumph and I discussed that we have utilities for comparing API files from specific URLs such as dev versions. We can download them and run grunt compare-phet-io-api or something. This wrapper seems good enough for clients and no more work is needed for this milestone, closing.