While I appreciate what you are trying to do, @olibaa, this is not how I think it should be done.

Please read very carefully what I wrote here.
I do not want to add getters for every possible slice.
They are simply unnecessary and add a huge amount of bloat for zero benefit.

What I recommend here is that you add a whitelist of fields that your code should process.
So, for example, we have only a single field currently that we want to add to the whitelist: PushEvent.Commits.

Then, on lines 140-142 of github/gen-accessors.go, you would check this whitelist and only call t.addArrayType if the current field matches an item in the whitelist (which itself could simply be a var whitelistSliceGetters = map[string]bool{ ...: true} to make lookup super-easy).

That way, when we look at the diffs of github/github-accessors.go and github/github-accessors_test.go, we should only see one new field in this PR... the one for PushEvent.Commits.

How does that sound to you?

Beautiful, @olibaa! Well done!
LGTM.

Awaiting second LGTM+Approval from any other contributor to this repo before merging.