When a Dangerfile has an error, raise the error back to the PR instea…

…d of just the console.

changelog.md

@@ -2,7 +2,7 @@
 
 ### Master
 
-
+* When a Dangerfile fails to eval, send a message to the PR - orta
 
 ### 0.14.2
 

source/runner/Executor.ts

@@ -6,6 +6,7 @@ import { DangerResults } from "../dsl/DangerResults"
 import { template as githubResultsTemplate } from "./templates/githubIssueTemplate"
 import { createDangerfileRuntimeEnvironment, runDangerfileEnvironment } from "./DangerfileRunner"
 import { DangerfileRuntimeEnv } from "./types"
+import exceptionRaisedTemplate from "./templates/exceptionRaisedTemplate"
 
 import * as debug from "debug"
 import * as chalk from "chalk"
@@ -53,7 +54,16 @@ export class Executor {
    */
 
   async runDanger(file: string, runtime: DangerfileRuntimeEnv) {
-    const results = await runDangerfileEnvironment(file, runtime)
+    let results = {} as DangerResults
+
+    // If an eval of the Dangerfile fails, we should generate a
+    // message that can go back to the CI
+    try {
+      results = await runDangerfileEnvironment(file, runtime)
+    } catch (error) {
+      results = this.resultsForError(error)
+    }
+
     await this.handleResults(results)
     return results
   }
@@ -87,7 +97,7 @@ export class Executor {
    * @param {DangerResults} results a JSON representation of the end-state for a Danger run
    */
   async handleResultsPostingToSTDOUT(results: DangerResults) {
-    const {fails, warnings, messages, markdowns} = results
+    const { fails, warnings, messages, markdowns } = results
 
     const table = [
       { name: "Failures", messages: fails.map(f => f.message) },
@@ -127,7 +137,7 @@ export class Executor {
    */
   async handleResultsPostingToPlatform(results: DangerResults) {
     // Delete the message if there's nothing to say
-    const {fails, warnings, messages, markdowns} = results
+    const { fails, warnings, messages, markdowns } = results
 
     const failureCount = [...fails, ...warnings].length
     const messageCount = [...messages, ...markdowns].length
@@ -160,4 +170,20 @@ export class Executor {
       await this.handleResultsPostingToSTDOUT(results)
     }
   }
+
+  /**
+   * Takes an error (maybe a bad eval) and provides a DangerResults compatible object
+   * @param error Any JS error
+   */
+  resultsForError(error: Error) {
+    // Need a failing error, otherwise it won't fail CI.
+    console.error(chalk.red("Danger has errored"))
+    console.error(error)
+    return {
+      fails: [{ message: "Running your Dangerfile has Failed" }],
+      warnings: [],
+      messages: [],
+      markdowns: [exceptionRaisedTemplate(error)]
+    }
+  }
 }

source/runner/_tests/_executor.test.ts

@@ -21,11 +21,31 @@ describe("setup", () => {
     expect(platform.getPlatformDSLRepresentation).toBeCalled()
   })
 
-  it("gets diff / pr info in setup", async () => {
+  it("gets diff / pr info / utils in setup", async () => {
     const exec = new Executor(new FakeCI({}), new FakePlatform(), defaultConfig)
     const dsl = await exec.dslForDanger()
     expect(dsl.git).toBeTruthy()
     expect(dsl.github).toBeTruthy()
+    expect(dsl.utils).toBeTruthy()
+  })
+
+  it("Creates a DangerResults for a raising dangerfile", async () => {
+    const platform = new FakePlatform()
+    const exec = new Executor(new FakeCI({}), platform, defaultConfig)
+
+    // This is a real error occuring when Danger modifies the Dangerfile
+    // as it is given a path of ""
+    const error = {
+      name: "Error",
+      message: "ENOENT: no such file or directory",
+    }
+
+    const results = await exec.runDanger("", {} as any)
+    expect(results.fails.length).toBeGreaterThan(0)
+
+    const markdown = results.markdowns[0]
+    expect(markdown).toMatch(error.name)
+    expect(markdown).toMatch(error.message)
   })
 
   it("Deletes a post when there are no messages", async () => {

source/runner/templates/exceptionRaisedTemplate.ts

@@ -0,0 +1,12 @@
+const quotes = "```"
+
+export default (error: Error) => `
+## Danger has errored
+
+Error: ${error.name}
+
+${quotes}sh
+${error.stack}
+${quotes}
+
+`