Add a bail-out flag to only changed

[tmeasday]

We need a way to flag to --only-change a glob of files that should trigger a bailout, something like --skip-only-changed-for="**/*.mjml".

┆Issue is synchronized with this Asana task by Unito

[zol]

Yeah this is important to add and document before we ship this feature to everyone because I know from talking to people firsthand that there are all sorts of quirky build time hacks floating around out there.

I'd like to think of a better name though, skip-only-changed has a confusing double negative in it.

@gert or @tmeasday what does the [branch] parameter to --only-changed do exactly and could that be used separately to --only-changed?

[tmeasday]

We are thinking we will call this --externals

[zol]

By 'this' do you mean instead of --skip-only-changed? What is the [branch] parameter for? I'm wondering whether this could be broken out as an independent parameter and then the argument to --only-changed could be the externals list.

[ghengeveld]

Implemented here: #355

[tmeasday]

The [branch] parameter is for saying "only do --only-changed if we are on this branch". It is a standard pattern we have in the CLI, for instance for --auto-accept-changes=master.

I'm wondering whether this could be broken out as an independent parameter and then the argument to --only-changed could be the externals list

To me that would be confusing though. If I read --only-changed=*.sass I would read that to mean "only run chromatic when sass files have changed", which isn't quite what we mean. We mean "run every chromatic test when sass files have changed, otherwise only run the changed files".

Also @ghengeveld mentioned the possibility of the externals list having meaning outside of the --only-changed feature.

[zol]

Sgtm, let's go with --externals

[tmeasday]

Heh, already done: #355