If pungi configuration and some other input data doesn't change pungi should create same output. Here I do not care about timestamps of files or even contents which depends on timestamps (e.g. repodata).

I'd like to have all this input which somehow affect compose result written in some input compose manifest. Then I'd like to use this input data to determine:
- if it hasn't changed since last compose running pungi won't produce different result - there is no need to start pungi.
- If this metadata is different it may produce different result - I need to start pungi to find that out.