Add --exists $LABEL to label command

This allows CI builds to check for existence of a label without
grepping for text in the label output.

Author: stabbylambda

docs/pages/blog/using-shipit.mdx

@@ -58,7 +58,7 @@ For example,. the following will only run the test:visual script when the PR has
 ```bash
 export PATH=$(npm bin):$PATH
 
-if [ `auto label --pr $PR_NUMBER | grep -c '^Visual'` -ne 0 ];
+if auto label --pr $PR_NUMBER --exists Visual;
 then
     npm run test:visual
 fi

docs/pages/docs/extras/label.md

@@ -6,7 +6,7 @@ The following will only run the test:visual script when the PR has has the
 ```bash
 export PATH=$(npm bin):$PATH
 
-if [ auto label --pr $PR_NUMBER | grep -c '^Visual' -ne 0 ];
+if auto label --pr $PR_NUMBER --exists Visual;
 then
   npm run test:visual
 fi

packages/cli/src/parse-args.ts

@@ -272,6 +272,12 @@ export const commands: AutoCommand[] = [
  "Get the labels for a pull request. Doesn't do much, but the return value lets you write you own scripts based off of the PR labels!",
  options: [
  { ...pr, description: `${pr.description} (defaults to last merged PR)` },
+ {
+ name: "exists",
+ type: String,
+ group: "main",
+ description: "Checks for existence of a specific label",
+ },
  ],
  examples: ["{green $} auto label --pr 123"],
  },

packages/cli/src/run.ts

@@ -15,6 +15,7 @@ import Auto, {
  IShipItOptions,
  IVersionOptions,
  INextOptions,
+ LabelExistsError,
 } from "@auto-it/core";
 import endent from "endent";
 import on from "await-to-js";
@@ -115,7 +116,7 @@ export async function run(command: string, args: ApiOptions) {
       `);
  console.log("");
  auto.logger.verbose.error(error);
- } else {
+ } else if (!(error instanceof LabelExistsError)) {
  console.log(error);
  }
 

packages/core/src/__tests__/auto.test.ts

@@ -314,6 +314,33 @@ describe("Auto", () => {
  expect(console.log).toHaveBeenCalledWith("foo");
  });
 
+ test("should check for a given label", async () => {
+ const auto = new Auto(defaults);
+ auto.logger = dummyLog();
+ await auto.loadConfig();
+
+ const getLabels = jest.fn();
+ auto.git!.getLabels = getLabels;
+ getLabels.mockReturnValueOnce(["foo"]);
+ jest.spyOn(console, "log").mockImplementation();
+
+ await auto.label({ pr: 13, exists: "foo" });
+ expect(console.log).toHaveBeenCalledWith("foo");
+ });
+
+ test("should throw if a check for a label fails", async () => {
+ const auto = new Auto(defaults);
+ auto.logger = dummyLog();
+ await auto.loadConfig();
+
+ const getLabels = jest.fn();
+ auto.git!.getLabels = getLabels;
+ getLabels.mockReturnValueOnce(["bar"]);
+ jest.spyOn(console, "log").mockImplementation();
+
+ await expect(auto.label({ pr: 13, exists: "foo" })).rejects.toThrow();
+ });
+
  test("should get labels for last merged PR", async () => {
  const auto = new Auto(defaults);
  auto.logger = dummyLog();

packages/core/src/auto-args.ts

@@ -14,6 +14,9 @@ export interface ICreateLabelsOptions {
 export interface ILabelOptions {
  /** PR to get the labels for */
  pr?: number;
+
+ /** Label to check for */
+ exists?: string;
 }
 
 export interface IPRCheckOptions {

packages/core/src/auto.ts

@@ -303,6 +303,17 @@ function escapeRegExp(str: string) {
  return str.replace(/[.*+?^${}()|[\]\\]/g, "\\$&"); // $& means the whole matched string
 }
 
+/** The Error that gets thrown when a label existence check fails */
+export class LabelExistsError extends Error {
+ /**
+   * @param label - the label we were checking existence for
+   */
+ constructor(label: string) {
+ super(`The label ${label} does not exist`);
+ Object.setPrototypeOf(this, new.target.prototype); // restore prototype chain
+ }
+}
+
 /**
  * The "auto" node API. Its public interface matches the
  * commands you can run from the CLI
@@ -751,7 +762,7 @@ export default class Auto {
  /**
    * Get the labels on a specific PR. Defaults to the labels of the last merged PR
    */
- async label({ pr }: ILabelOptions = {}) {
+ async label({ pr, exists }: ILabelOptions = {}) {
  if (!this.git) {
  throw this.createErrorMessage();
  }
@@ -779,6 +790,14 @@ export default class Auto {
  }
  }
 
+ if (exists) {
+ if (labels.indexOf(exists) === -1) {
+ throw new LabelExistsError(exists);
+ }
+
+ return;
+ }
+
  if (labels.length) {
  console.log(labels.join("\n"));
  }