Usage of undeclared output?

Hi,

docs say the following:

> You will receive an error if you attempt to set an output value that was not declared in the action’s metadata file.

but actions/typescript-action produces output https://github.com/actions/typescript-action/blob/releases/v1/src/main.ts#L13 which is not declared in action’s metadata https://github.com/actions/typescript-action/blob/releases/v1/action.yml.

What is this - an outdated doc or a bug in the actions system?

It is also possible to provide an arbitrary output in “run” step with “echo”. This looks like a very poweful option to prepare variables for next steps but will this still be working in future?

sample demonstrating both:

https://github.com/maxkomarychev/test-undeclared-output/commit/f184263650425dd4095afdd5264d1498ee8cf733/checks?check_suite_id=269037574

In addition the same question about inputs: it is currently possible to send and consume any input that is not declared in action.yml.