Rules

Rules are a new concept in this fork of Danger Kotlin that allow you to modularize your rules and checks in an ordered way without having to crowd all your logic into a single file.

Creating a rule

Use the top-level rule(…) function to register a new rule with an id, like so:

import systems.danger.kotlin.rule.*

rule("title-check") {
  if (!github.pullRequest.title.matches(TITLE_REGEX)) {
    fail("The title of this pull request must match the format \"JIRA-123: Description of Changes\"")
  }

  RuleResult.Continue
}

Depending on other rules

You can also have rules depend on the execution of other rules. Each rule returns a RuleResult that dictates whether the rule chain continues to execute, or exits entirely.

import systems.danger.kotlin.rule.*

rule("bot-check") {
  if (github.pullRequest.user.type == GitHubUserType.BOT) {
    RuleResult.Exit
  } else {
    RuleResult.Continue
  }
}

//...

rule(id = "title-check", "bot-check") {
  if (!github.pullRequest.title.matches(TITLE_REGEX)) {
    fail("The title of this pull request must match the format \"JIRA-123: Description of Changes\"")
  }

  RuleResult.Continue
}

If the bot-check rule returns RuleResult.Exit then the title-check rule will not execute.

Applying rules

To apply your rule chain in your main Dangerfile just import your other rule script files add applyRules() inside the DangerDSL, like so:

@file:Import("rules/bot-check.df.kts")
@file:Import("rules/title-check.df.kts")

import systems.danger.kotlin.*
import systems.danger.kotlin.rule.*

danger(args) {
  applyRules()
}

or use the @file:ImportDirectory annotation to import an entire directory of Dangerfile scripts into your main file

@file:ImportDirectory("rules")

import systems.danger.kotlin.*
import systems.danger.kotlin.rule.*

danger(args) {
  applyRules()
}