feat: merge in accordance with branch protection rules

.eslintrc.yaml

@@ -14,6 +14,10 @@ overrides:
       max-lines-per-function: 'off'
       no-magic-numbers: 'off'
       max-statements: 'off'
+  - files:
+      - src/**/computeRequiresStrictStatusChecksForRefs.*
+    rules:
+      'unicorn/prevent-abbreviations': 'off'
 parserOptions:
   ecmaVersion: 2020
   project: tsconfig.json

README.md

@@ -207,6 +207,24 @@ jobs:
 `GITHUB_LOGIN` option supports
 [micromatch](https://github.com/micromatch/micromatch).
 
+### Opting in for using GitHub preview APIs
+
+You may opt-in for using GitHub preview APIs, which enables the action to
+respect strict branch protection rules configured for the repository
+(`Require status checks to pass before merging` and
+`Require branches to be up to date before merging` options).
+
+```yaml
+jobs:
+  merge-me:
+    steps:
+      - name: Merge me!
+        uses: ridedott/merge-me-action@v2
+        with:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          ENABLE_GITHUB_API_PREVIEW: true
+```
+
 ### Use of configurable pull request merge method
 
 By default, this GitHub Action assumes merge method is `SQUASH`. You can

action.yml

@@ -13,6 +13,12 @@ inputs:
   GITHUB_TOKEN:
     description: 'A GitHub token.'
     required: true
+  ENABLE_GITHUB_API_PREVIEW:
+    default: 'false'
+    description: >
+      Indicates if GitHub preview APIs can be used to access pull request fields
+      that provide more detailed information about the merge state.
+    required: false
   MERGE_METHOD:
     default: SQUASH
     description:

src/common/__snapshots__/getPullRequestInformation.spec.ts.snap

@@ -0,0 +1,36 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`getPullRequestInformation returns pull request information with mergeStateStatus field 1`] = `
+Object {
+  "authorLogin": "test-author",
+  "commitMessage": "test message",
+  "commitMessageHeadline": "test message headline",
+  "mergeStateStatus": "CLEAN",
+  "mergeableState": "MERGEABLE",
+  "merged": false,
+  "pullRequestId": "123",
+  "pullRequestNumber": 1,
+  "pullRequestState": "OPEN",
+  "pullRequestTitle": "test",
+  "repositoryName": "test-repository",
+  "repositoryOwner": "test-owner",
+  "reviewEdges": Array [],
+}
+`;
+
+exports[`getPullRequestInformation returns pull request information without mergeStateStatus field 1`] = `
+Object {
+  "authorLogin": "test-author",
+  "commitMessage": "test message",
+  "commitMessageHeadline": "test message headline",
+  "mergeableState": "MERGEABLE",
+  "merged": false,
+  "pullRequestId": "123",
+  "pullRequestNumber": 1,
+  "pullRequestState": "OPEN",
+  "pullRequestTitle": "test",
+  "repositoryName": "test-repository",
+  "repositoryOwner": "test-owner",
+  "reviewEdges": Array [],
+}
+`;

src/common/computeRequiresStrictStatusChecksForRefs.spec.ts

@@ -0,0 +1,93 @@
+import { computeRequiresStrictStatusChecksForRefs as computeRequiresStrictStatusChecksForReferences } from './computeRequiresStrictStatusChecksForRefs';
+
+/**
+ * Tests
+ */
+describe('computeRequiresStrictStatusChecksForRefs', (): void => {
+  it('returns false for all refs when no branch protection rules exist for the repository', (): void => {
+    expect.assertions(1);
+
+    const result = computeRequiresStrictStatusChecksForReferences(
+      [],
+      ['master', 'dev'],
+    );
+
+    expect(result).toStrictEqual([false, false]);
+  });
+
+  it('returns false for all refs when none of the branch protection rule patterns match provided refs', (): void => {
+    expect.assertions(1);
+
+    const result = computeRequiresStrictStatusChecksForReferences(
+      [
+        {
+          pattern: 'test1',
+          requiresStrictStatusChecks: true,
+        },
+        {
+          pattern: 'test2',
+          requiresStrictStatusChecks: true,
+        },
+      ],
+      ['master', 'dev'],
+    );
+
+    expect(result).toStrictEqual([false, false]);
+  });
+
+  it('returns false for all refs when all matching branch protection rule patterns do not require strict status checks', (): void => {
+    expect.assertions(1);
+
+    const result = computeRequiresStrictStatusChecksForReferences(
+      [
+        {
+          pattern: 'dev',
+          requiresStrictStatusChecks: false,
+        },
+        {
+          pattern: 'master',
+          requiresStrictStatusChecks: false,
+        },
+      ],
+      ['master', 'dev'],
+    );
+
+    expect(result).toStrictEqual([false, false]);
+  });
+
+  it('returns true for all refs when branch protection rule patterns match provided refs with wildcard', (): void => {
+    expect.assertions(1);
+
+    const result = computeRequiresStrictStatusChecksForReferences(
+      [
+        {
+          pattern: 'test*',
+          requiresStrictStatusChecks: true,
+        },
+      ],
+      ['test', 'testing', 'master'],
+    );
+
+    expect(result).toStrictEqual([true, true, false]);
+  });
+
+  it('returns true for refs when matching branch protection rules require strict status checks', (): void => {
+    expect.assertions(1);
+
+    const result = computeRequiresStrictStatusChecksForReferences(
+      [
+        {
+          pattern: 'dev',
+          requiresStrictStatusChecks: true,
+        },
+        {
+          pattern: 'master',
+          requiresStrictStatusChecks: false,
+        },
+      ],
+      ['master', 'dev'],
+    );
+
+    expect(result).toStrictEqual([false, true]);
+  });
+});

src/common/computeRequiresStrictStatusChecksForRefs.ts

@@ -0,0 +1,21 @@
+import { isMatch } from 'micromatch';
+
+import { BranchProtectionRule } from './listBranchProtectionRules';
+
+/**
+ * Returns an array of booleans indicating whether the provided pull requests
+ * require their branches to be up to date before merging.
+ */
+export const computeRequiresStrictStatusChecksForRefs = (
+  branchProtectionRules: BranchProtectionRule[],
+  refs: string[],
+): boolean[] =>
+  refs.map((reference: string): boolean =>
+    branchProtectionRules.some(
+      ({
+        pattern,
+        requiresStrictStatusChecks,
+      }: BranchProtectionRule): boolean =>
+        isMatch(reference, pattern) && requiresStrictStatusChecks === true,
+    ),
+  );

src/common/getPullRequestInformation.spec.ts

@@ -0,0 +1,192 @@
+/* cspell:ignore reqheaders */
+
+import { getOctokit } from '@actions/github';
+import { StatusCodes } from 'http-status-codes';
+import * as nock from 'nock';
+
+import {
+  MergeableState,
+  MergeStateStatus,
+  PullRequestState,
+  ReviewEdges,
+} from '../types';
+import { getMergeablePullRequestInformationByPullRequestNumber } from './getPullRequestInformation';
+
+/**
+ * Test utilities
+ */
+const octokit = getOctokit('SECRET_GITHUB_TOKEN');
+const repositoryName = 'test-repository';
+const repositoryOwner = 'test-owner';
+const pullRequestNumber = 1;
+
+const pullRequestFields = (githubPreviewApiEnabled: boolean): string => {
+  const fields = [
+    `author {
+       login
+    }`,
+    `commits(last: 1) {
+      edges {
+        node {
+          commit {
+            author {
+              name
+            }
+            messageHeadline
+            message
+          }
+        }
+      }
+    }`,
+    'id',
+    'mergeable',
+    'merged',
+    ...(githubPreviewApiEnabled ? ['mergeStateStatus'] : []),
+    'number',
+    `reviews(last: 1, states: APPROVED) {
+      edges {
+        node {
+          state
+        }
+      }
+    }`,
+    'state',
+    'title',
+  ];
+
+  return `{
+    ${fields.join('\n')}
+  }`;
+};
+
+const findPullRequestInfoByNumberQuery = (
+  githubPreviewApiEnabled: boolean,
+): string => `
+  query FindPullRequestInfoByNumber(
+    $repositoryOwner: String!,
+    $repositoryName: String!,
+    $pullRequestNumber: Int!
+  ) {
+    repository(owner: $repositoryOwner, name: $repositoryName) {
+      pullRequest(number: $pullRequestNumber) ${pullRequestFields(
+        githubPreviewApiEnabled,
+      )}
+    }
+  }
+`;
+
+interface GraphQLResponse {
+  repository: {
+    pullRequest: {
+      author: {
+        login: string;
+      };
+      commits: {
+        edges: Array<{
+          node: {
+            commit: {
+              author: {
+                name: string;
+              };
+              message: string;
+              messageHeadline: string;
+            };
+          };
+        }>;
+      };
+      id: string;
+      mergeStateStatus?: MergeStateStatus;
+      mergeable: MergeableState;
+      merged: boolean;
+      number: number;
+      reviews: {
+        edges: ReviewEdges[];
+      };
+      state: PullRequestState;
+      title: string;
+    };
+  };
+}
+
+const makeGraphQLResponse = (
+  includeMergeStateStatus: boolean,
+): GraphQLResponse => ({
+  repository: {
+    pullRequest: {
+      author: {
+        login: 'test-author',
+      },
+      commits: {
+        edges: [
+          {
+            node: {
+              commit: {
+                author: {
+                  name: 'Test Author',
+                },
+                message: 'test message',
+                messageHeadline: 'test message headline',
+              },
+            },
+          },
+        ],
+      },
+      id: '123',
+      ...(includeMergeStateStatus ? { mergeStateStatus: 'CLEAN' } : {}),
+      mergeable: 'MERGEABLE',
+      merged: false,
+      number: pullRequestNumber,
+      reviews: {
+        edges: [],
+      },
+      state: 'OPEN',
+      title: 'test',
+    },
+  },
+});
+
+/**
+ * Tests
+ */
+describe('getPullRequestInformation', (): void => {
+  it.each<[string, boolean]>([
+    ['without mergeStateStatus field', false],
+    ['with mergeStateStatus field', true],
+  ])(
+    'returns pull request information %s',
+    async (_: string, githubPreviewApiEnabled: boolean): Promise<void> => {
+      expect.assertions(1);
+
+      nock('https://api.github.com', {
+        reqheaders: {
+          accept: githubPreviewApiEnabled
+            ? 'application/vnd.github.merge-info-preview+json'
+            : 'application/vnd.github.v3+json',
+        },
+      })
+        .post('/graphql', {
+          query: findPullRequestInfoByNumberQuery(githubPreviewApiEnabled),
+          variables: {
+            pullRequestNumber,
+            repositoryName,
+            repositoryOwner,
+          },
+        })
+        .reply(StatusCodes.OK, {
+          data: makeGraphQLResponse(githubPreviewApiEnabled),
+        });
+
+      const result = await getMergeablePullRequestInformationByPullRequestNumber(
+        octokit,
+        {
+          pullRequestNumber,
+          repositoryName,
+          repositoryOwner,
+        },
+        { githubPreviewApiEnabled },
+      );
+
+      expect(result).toMatchSnapshot();
+    },
+  );
+});