fix(gatsby): Exclude build time when calculating dirty Ids

[sidharthachatterjee]

This significantly speeds up consecutive builds if all changed is buildTime in the Site node

Co authored with @ascorbic

[sidharthachatterjee]

Closing this for now because some folks might actually use buildTime 😛

[sidharthachatterjee]

We can't do what we added in 299626f because some folks might just use buildTime

Now there's an alternative that @pieh brought up:

• Create a separate top level Node for buildTime
• Calculate and put it there (in the internal-data-bridge internal plugin)
• Add a link resolver for buildTime that does a passthrough to the new Node

This would let us track dependencies when buildTime is used in a query (at query resolution time) but not affect the Site node (which includes the heavily used siteMetadata)

This would however need some more work for data dependency tracking to work correctly:

• The buildTime node would need to be of type Node - this would make it to show up in root query fields and this just pollute root level fields unnecessarily and it would be preferable to not add fields for it to root query

Also there used to be ignoreType that kinda would suffice for this

@freiksenet Do you remember why we stopped supporting it?

[freiksenet]

ignoreType was gone as not important somewhere in schema customization time, I think it was always quite a hack.

[sidharthachatterjee]

@freiksenet How do you feel about adding it back? 😛 Or do you have another preferred way to exclude something from appearing as a top level field in Query?

[freiksenet]

I don't think number of fields in root fields is really an important consideration. I'd call it SiteBuildTime so that it's analogous with other Gatsby site stuff.

[sidharthachatterjee]

Closed in favor of #21827