Handle fancy wildcard branch patterns

[lox]

Based on feedback in https://forum.buildkite.community/t/cli-steps-dont-run-when-there-is-a-negated-branch-filter/400/5, this adds support for different branch filter patterns.

@keithpitt I'd love some feedback on what the actual types of patterns that are supported are 😅

[keithpitt]

These are "matching" fixtures. Left is the pattern, right is the branch. All return "yes, it's a match"

# empty branch names
[ "foo", nil ],
[ "", nil ],
[ "    ", nil ],

# empty branch configs
[ nil, "foo" ],
[ nil, "" ],
[ nil, "       " ],

# single name branch matches
[ "foo bar", "foo" ],
[ "foo             bar", "bar" ],

# with whitespace
[ "    master   ", "master" ],
[ "master   ", "master" ],
[ "   master", "master" ],

# ones with a slash
[ "feature/authentication", "feature/authentication" ],

# not-checking
[ "!foo", "master" ],
[ "!release/production !release/test", "master" ],

# prefix wildcards
[ "*-do-the-thing", "can-you-do-the-thing" ],
[ "!*-do-the-thing", "can-you-do-the-thing-please" ],

# wildcards
[ "release/*", "release/foo" ],
[ "release/*", "release/bar/bing" ],
[ "release-*", "release-thingy" ],
[ "release-* release/*", "release-thingy" ],
[ "release-* release/*", "release/thingy" ],
[ "this-*-thing-is-the-*", "this-ruby-thing-is-the-worst" ],
[ "this-*-thing-is-the-*", "this-regex-thing-is-the-best" ],
[ "this-*-thing-is-the-*", "this-*-thing-is-the-*" ],
[ "this-*-thing-is-the-*", "this--thing-is-the-best-" ],

Here's are the ones that return false, not a match:

# branch names
[ "foo         bar", "bang" ],

# not-matchers
[ "!foo bar", "foo" ],
[ "!release/*", "release/foo" ],
[ "!release/*", "release/bar" ],
[ "!refs/tags/*", "refs/tags/production" ],
[ "!release/production !release/test", "release/production" ],
[ "!release/production !release/test", "release/test" ],

# ones with a slash
[ "feature/authentication", "update/deployment" ],

# wildcards
[ "release-*", "release/thingy" ],
[ "release-*", "master" ],
[ "*-do-the-thing", "this-is-not-the-thing" ],

[keithpitt]

Feel free to pilfer the data and add them into the test suite!

[keithpitt]

BK backend doesn't support branches: "foo, bar" - is that what this bit is for? Or is this something else?

[lox]

Ok cool, not sure where I got that from, but will ditch it.

[lox]

Mind reviewing where I got up to when you get a minute @keithpitt?

[lox]

Gonna yolo merge this.

[gerrywastaken]

Thanks @lox!