Confusing results regarding churn (`start_ago` default not clear)

[etagwerker]

Hi there,

I may have ran into an edge case. I recently started maintaining a project that had been inactive for a while (metric_fu). Then I tried to run attractor report and I ended up with this report:

There was clearly something wrong with my project or the way that I called attractor report.

After reading the README I realized that there was a parameter to tell the library to use a start_ago value. I realized that maybe attractor's default was "too soon" for this particular project: https://github.com/julianrubisch/attractor/blob/master/lib/attractor/calculators/base_calculator.rb#L12

After specifying 10 years as start_ago and running this command:

attractor report --start_ago 10y

I ended up with this report:

This made me think and I thought about two things:

• Maybe defaults should be better documented? It could be a section in the README or a comment that ends up here: https://rubydoc.info/gems/attractor/Attractor/BaseReporter#initialize-instance_method
• Maybe the HTML report should include the start_ago value or the time interval that the report is using?
• Maybe the attractor help could document defaults and options for the report command? It could be something like attractor report --help that shows available options and defaults.

Before I work on any of this, I thought I'd run it by you and see what you think.

Thanks in advance! 😄