Chunk version checking

[slimbuck]

Followup to #4254.

This PR adds a chunk system runtime compatibility check based on the engine version.

Applications use StandardMaterial.chunks.APIVersion to specify which engine version the overridden chunks implement. If any of the overridden chunks have a newer API defined in the engine (or the chunk was removed), a warning is printed to the debug console.

This helps app developers know which chunks have changed in their apps and in what version.

[mvaligursky]

• Is there some public documentation to explain the user how to use the versioning?
• When we print some of these 'incorrect version' messages, could we include a link to PR with the change, or engine release notes for the version or similar, to guide them in how to fix it?

[slimbuck]

As part of engine v1.55 release I think we should start documenting chunk changes. Once we've decided where and how we can update the log message. (Though I am hesitant at the idea of printing URLs, seems a bit strange...).

Perhaps we can add a CHUNK_HISTORY.md file to the engine repo.

[willeastcott]

From a quick glance, it doesn't look like all this new functionality is restricted to a debug build. Is that right?

[slimbuck]

From a quick glance, it doesn't look like all this new functionality is restricted to a debug build. Is that right?

Yes the validation happens in all builds so that only valid chunks are used. The warning messages only appear in debug build.

[willeastcott]

My concern is that this is going to bloat the release build over time as we continue to bump versions. Do we really have to carry around what is essentially a debugging aid in production builds of apps?

[mvaligursky]

My concern is that this is going to bloat the release build over time as we continue to bump versions. Do we really have to carry around what is essentially a debugging aid in production builds of apps?

That's a good point. As long as the behaviour of the code with and without validation is the same (for example to always use user chunks, even when not up to date), we can drop the validation in release I think.

[slimbuck]

Done. Also corrected chunk versions.

[Maksims]

By not providing version property in chunks, it will lead to warnings? So pretty much every current developer will get a lot of warnings in their code after this update.

[slimbuck]

By not providing version property in chunks, it will lead to warnings? So pretty much every current developer will get a lot of warnings in their code after this update.

@Maksims user will get warnings for chunks listed in chunk-validation.js, not all chunks. The message is only printed once and I have found them very useful.

[mvaligursky]

looks good to me.