fix(cli): handle empty GitHub repositories during SDK generation (#10365)

* fix(cli): handle empty GitHub repositories during SDK generation

---------

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: Niels Swimberghe <[email protected]>

Author: devin-ai-integration[bot]

packages/commons/github/package.json

@@ -34,6 +34,7 @@
   },
   "dependencies": {
     "octokit": "^4.1.4",
+    "simple-git": "^3.24.0",
     "tmp-promise": "^3.0.3"
   },
   "devDependencies": {

packages/commons/github/src/ClonedRepository.ts

@@ -86,6 +86,30 @@ export class ClonedRepository {
         await this.git.push();
     }
 
+    public async isRemoteEmpty(): Promise<boolean> {
+        await this.git.cwd(this.clonePath);
+        try {
+            const result = await this.git.raw(["ls-remote", "--heads", "origin"]);
+            return result.trim().length === 0;
+        } catch (_error) {
+            return true;
+        }
+    }
+
+    public async checkoutOrCreateLocal(branch: string): Promise<void> {
+        await this.git.cwd(this.clonePath);
+        try {
+            await this.git.checkout(branch);
+        } catch (_error) {
+            await this.git.checkoutLocalBranch(branch);
+        }
+    }
+
+    public async pushUpstream(branch: string): Promise<void> {
+        await this.git.cwd(this.clonePath);
+        await this.git.push("origin", branch, { "--set-upstream": null });
+    }
+
     public async overwriteLocalContents(sourceDirectoryPath: string): Promise<void> {
         const [sourceContents, destContents] = await Promise.all([
             readdir(sourceDirectoryPath),

packages/generator-cli/src/github/GitHub.ts

@@ -1,5 +1,5 @@
 import { cwd, resolve } from "@fern-api/fs-utils";
-import { cloneRepository } from "@fern-api/github";
+import { cloneRepository, parseRepository } from "@fern-api/github";
 import type { ClonedRepository } from "@fern-api/github/src/ClonedRepository";
 import { Octokit } from "@octokit/rest";
 
@@ -27,16 +27,29 @@ export class GitHub {
                 installationToken: this.githubConfig.token
             });
 
-            const branch = this.githubConfig.branch ?? (await repository.getDefaultBranch());
+            const isEmptyRepo = await repository.isRemoteEmpty();
+
+            let branch: string;
+            if (isEmptyRepo) {
+                branch = this.githubConfig.branch ?? "main";
+                await repository.checkoutOrCreateLocal(branch);
+            } else {
+                branch = this.githubConfig.branch ?? (await repository.getDefaultBranch());
+                await repository.checkout(branch);
+                await repository.pull(branch);
+            }
 
-            await repository.checkout(branch);
-            await repository.pull(branch);
             const fernIgnoreFiles = await this.getFernignoreFiles(repository);
             await repository.overwriteLocalContents(sourceDirectory);
             await repository.add(".");
             await this.restoreFiles(repository, fernIgnoreFiles);
             await repository.commit("SDK Generation");
-            await repository.push();
+
+            if (isEmptyRepo) {
+                await repository.pushUpstream(branch);
+            } else {
+                await repository.push();
+            }
         } catch (error) {
             // TODO: migrate this to use @fern-api/logger
             console.error("Error during GitHub push:", error);
@@ -54,13 +67,23 @@ export class GitHub {
                 installationToken: this.githubConfig.token
             });
 
-            const baseBranch = this.githubConfig.branch ?? (await repository.getDefaultBranch());
+            const isEmptyRepo = await repository.isRemoteEmpty();
+
+            let baseBranch: string;
+            if (isEmptyRepo) {
+                baseBranch = this.githubConfig.branch ?? "main";
+                await repository.checkoutOrCreateLocal(baseBranch);
+                await repository.commit("Initial commit");
+                await repository.pushUpstream(baseBranch);
+            } else {
+                baseBranch = this.githubConfig.branch ?? (await repository.getDefaultBranch());
+                await repository.checkout(baseBranch);
+                await repository.pull(baseBranch);
+            }
 
             const now = new Date();
             const formattedDate = now.toISOString().replace("T", "_").replace(/:/g, "-").replace(/\..+/, "");
             const prBranch = `fern-bot/${formattedDate}`;
-            await repository.checkout(baseBranch);
-            await repository.pull(baseBranch);
             await repository.checkout(prBranch);
 
             const fernIgnoreFiles = await this.getFernignoreFiles(repository);
@@ -74,10 +97,8 @@ export class GitHub {
                 auth: this.githubConfig.token
             });
             // Use octokit directly to create the pull request
-            const [owner, repo] = this.githubConfig.uri.split("/");
-            if (!owner || !repo) {
-                throw new Error(`Invalid repository URI: ${this.githubConfig.uri}`);
-            }
+            const parsedRepo = parseRepository(this.githubConfig.uri);
+            const { owner, repo } = parsedRepo;
             const head = `${owner}:${prBranch}`;
             try {
                 await octokit.pulls.create({

packages/generator-cli/versions.yml

@@ -1,4 +1,11 @@
 # yaml-language-server: $schema=../../versions-yml.schema.json
+- changelogEntry:
+    - summary: |
+        Fix an issue where the `generator-cli github pr ...` and `generator-cli github push` commands would fail when the GitHub repository is empty.
+      type: fix
+  createdAt: "2025-11-06"
+  version: 0.4.2
+
 - changelogEntry:
     - summary: |
         Use proper title case in README generator. Conjunctions and prepositions are now lowercased when they appear in the middle of titles.