`--compare-branch` should default to `@{upstream}` and not `origin/master`

Not all branches are forked off a branch named master in remote origin. When an upstream has been configured for current branch it should be the first choice; when there is none origin/master is still the obvious default.

[Bachmann1234]

I agree it’s frustrating. But I can’t simply change the default without breaking existing users workflows

And while githubs default is main gitlab and git itself still very much default to master. I think main is a better name but it’s not relevant to this project.

I’m the maintainer of this project. As such I try and provide timely feedback on prs. If I get a bug report with enough info to act on I reproduce it in a test and fix it. Whenever a fix or a feature comes in I release it asap.

But I typically don’t implement new functionality. Someone has to care enough to implement it themselves.

In this case I’ll take a look, probably this weekend. I might just resort to providing a more helpful error message or perhaps trying main if master does not exist. As far as I know there is not really a clean way of detecting the “main” branch.

[jaraco]

Additionally, the ecosystem is transitioning from master to main as the default branch name, so origin/master is no longer an obvious default. I’d recommend to infer the upstream branch. I’d even go as far as to say that main should be the preferred fallback, but if any of main, master, default, or possibly others are present, then they will be preferred (in that order) if no upstream is indicated.