fix: handle empty repository as if it has no files (#4863)

* test: add test for empty repository

* fix: handle empty repository as if it has no files

* fix lint

packages/git-file-utils/src/git-file-utils.ts

@@ -13,9 +13,10 @@
 // limitations under the License.
 
 import {Octokit} from '@octokit/rest';
-import {RequestError} from '@octokit/types';
 import {basename, extname} from 'path';
 import {Minimatch} from 'minimatch';
+/* eslint-disable-next-line node/no-extraneous-import */
+import {RequestError} from '@octokit/request-error';
 
 export const DEFAULT_FILE_MODE = '100644';
 
@@ -420,19 +421,30 @@ export class BranchFileCache {
     sha: string,
     recursive: boolean
   ): Promise<TreeResponse> {
-    const {
-      data: {tree, truncated},
-    } = await this.octokit.git.getTree({
-      owner: this.repository.owner,
-      repo: this.repository.repo,
-      tree_sha: sha,
-      // fetching tree non-recursively requires omitting the param
-      recursive: recursive ? 'true' : undefined,
-    });
-    return {
-      tree,
-      truncated,
-    };
+    try {
+      const {
+        data: {tree, truncated},
+      } = await this.octokit.git.getTree({
+        owner: this.repository.owner,
+        repo: this.repository.repo,
+        tree_sha: sha,
+        // fetching tree non-recursively requires omitting the param
+        recursive: recursive ? 'true' : undefined,
+      });
+      return {
+        tree,
+        truncated,
+      };
+    } catch (e) {
+      if (e instanceof RequestError && e.status === 409) {
+        // handle empty repository
+        return {
+          tree: [],
+          truncated: false,
+        };
+      }
+      throw e;
+    }
   }
 
   /**

packages/git-file-utils/test/git-file-utils.ts

@@ -130,6 +130,18 @@ describe('BranchFileCache', () => {
       }, BranchNotFoundError);
       req.done();
     });
+
+    it('throws on empty repository', async () => {
+      const req = nock('https://api.github.com')
+        .get(
+          '/repos/testOwner/testRepo/git/trees/feature-branch?recursive=true'
+        )
+        .reply(409);
+      await assert.rejects(async () => {
+        await cache.getFileContents('missing-file');
+      }, FileNotFoundError);
+      req.done();
+    });
   });
 
   describe('with large repository', () => {