fix: handle pull request files returned as null (#1651)

* test: add failing test for graphQL not returning file nodes

* fix: handle pull request files returned as null

* fix pagination handling

src/github.ts

@@ -473,7 +473,7 @@ export class GitHub {
         return pr.mergeCommit && pr.mergeCommit.oid === graphCommit.sha;
       });
       if (pullRequest) {
-        const files = pullRequest.files.nodes.map(node => node.path);
+        const files = (pullRequest.files?.nodes || []).map(node => node.path);
         commit.pullRequest = {
           sha: commit.sha,
           number: pullRequest.number,
@@ -484,7 +484,7 @@ export class GitHub {
           labels: pullRequest.labels.nodes.map(node => node.name),
           files,
         };
-        if (pullRequest.files.pageInfo?.hasNextPage && options.backfillFiles) {
+        if (pullRequest.files?.pageInfo?.hasNextPage && options.backfillFiles) {
           this.logger.info(
             `PR #${pullRequest.number} has many files, backfilling`
           );

test/fixtures/commits-since-no-files.json

@@ -0,0 +1,61 @@
+{
+  "repository": {
+    "ref": {
+      "target": {
+        "history": {
+          "nodes": [
+            {
+              "associatedPullRequests": {
+                "nodes": [
+                  {
+                    "number": 7,
+                    "title": "feat: feature that will be plain merged",
+                    "baseRefName": "main",
+                    "headRefName": "feature-branch-plain-merge",
+                    "labels": {
+                      "nodes": []
+                    },
+                    "body": "",
+                    "mergeCommit": {
+                      "oid": "e6daec403626c9987c7af0d97b34f324cd84320a"
+                    },
+                    "files": null
+                  }
+                ]
+              },
+              "sha": "e6daec403626c9987c7af0d97b34f324cd84320a",
+              "message": "Merge pull request #7 from chingor13/feature-branch-plain-merge\n\nfeat: feature that will be plain merged"
+            },
+            {
+              "associatedPullRequests": {
+                "nodes": [
+                  {
+                    "number": 7,
+                    "title": "feat: feature that will be plain merged",
+                    "baseRefName": "main",
+                    "headRefName": "feature-branch-plain-merge",
+                    "labels": {
+                      "nodes": []
+                    },
+                    "body": "",
+                    "mergeCommit": {
+                      "oid": "b29149f890e6f76ee31ed128585744d4c598924c"
+                    },
+                    "files": {
+                      "nodes": []
+                    }
+                  }
+                ]
+              },
+              "sha": "b29149f890e6f76ee31ed128585744d4c598924c",
+              "message": "feat: feature-branch-plain-merge commit 2"
+            }
+          ],
+          "pageInfo": {
+            "hasNextPage": false
+          }
+        }
+      }
+    }
+  }
+}

test/github.ts

@@ -39,6 +39,7 @@ import * as codeSuggester from 'code-suggester';
 import {RawContent} from '../src/updaters/raw-content';
 import {HttpsProxyAgent} from 'https-proxy-agent';
 import {HttpProxyAgent} from 'http-proxy-agent';
+import {Commit} from '../src/commit';
 
 const fixturesPath = './test/fixtures';
 const sandbox = sinon.createSandbox();
@@ -542,6 +543,28 @@ describe('GitHub', () => {
     });
   });
 
+  describe('mergeCommitIterator', () => {
+    it('handles merged pull requests without files', async () => {
+      const graphql = JSON.parse(
+        readFileSync(
+          resolve(fixturesPath, 'commits-since-no-files.json'),
+          'utf8'
+        )
+      );
+      req.post('/graphql').reply(200, {
+        data: graphql,
+      });
+      const generator = github.mergeCommitIterator('main');
+      const commits: Commit[] = [];
+      for await (const commit of generator) {
+        commits.push(commit);
+      }
+      expect(commits).lengthOf(2);
+      snapshot(commits!);
+      req.done();
+    });
+  });
+
   describe('getCommitFiles', () => {
     it('fetches the list of files', async () => {
       req