fix(gatsby): don't ignore SOURCE_FILE_CHANGED event

[pieh]

Description

We are currently ignoring SOURCE_FILE_CHANGED event in reloadingData state. This seems to cause problems:

If we are in this state and we ignore that event, but

gatsby/packages/gatsby/src/services/start-webpack-server.ts

Lines 47 to 55 in a8f7101

	compiler.hooks.invalid.tap(`log compiling`, function () {
	if (!webpackActivity) {
	// mark webpack as pending if we are not in the middle of compilation already
	// when input is invalidated during compilation, webpack will automatically
	// run another compilation round before triggering `done` event
	report.pendingActivity({ id: `webpack-develop` })
	markWebpackStatusAsPending()
	}
	})

will mark webpack recompilation to run but it won't (until something else potentially in the future trigger another recompilation).

This might result in at least some runs getting stuck - GATSBY_DIAGNOSTIC_STUCK_STATUS_TIMEOUT reporting things like:

Activity "Building development bundle" of type "pending" is currently in state "NOT_STARTED"

This might also be source of at least some of double save issues

[vladar]

It makes perfect sense to me.

I guess the only thing that confuses me a little bit - why did we ignore SOURCE_FILE_CHANGED in the first place there? Maybe there was some edge case?

[ascorbic]

I ignored it because previously we weren't using it to decide whether to recompile, we were just using it to decide whether to extract queries. As we were about to extract queries anyway, we didn't need to add a flag to say to do it

[vladar]

Published in gatsby@3.0.4