feat: add support for pushing to empty remote repositories during migration

Author: CasLubbers

src/operator/git-repository.ts

@@ -90,6 +90,42 @@ export class GitRepository {
     }
   }
 
+  /**
+   * Checks if the remote repository is empty (has no branches).
+   * This is useful for migration scenarios where we want to push to an empty external repo.
+   */
+  private async isRemoteEmpty(): Promise<boolean> {
+    try {
+      // git ls-remote --heads returns nothing if no branches exist
+      const result = await this.git.listRemote(['--heads', 'origin'])
+      const isEmpty = result.trim() === ''
+      if (isEmpty) {
+        this.d.info('Remote repository is empty (no branches found)')
+      }
+      return isEmpty
+    } catch (error) {
+      // If ls-remote fails, assume remote is not empty to avoid accidental pushes
+      this.d.warn('Failed to check if remote is empty, assuming not empty:', getErrorMessage(error))
+      return false
+    }
+  }
+
+  /**
+   * Pushes local content to an empty remote repository.
+   * Used during migration from internal Gitea to external Git.
+   */
+  private async pushToEmptyRemote(): Promise<void> {
+    try {
+      this.d.info('Pushing local content to empty remote repository...')
+      // Push current branch (main) to origin, setting upstream
+      await this.git.push(['--set-upstream', 'origin', 'main'])
+      this.d.info('Successfully pushed local content to remote repository')
+    } catch (error) {
+      this.d.error('Failed to push to empty remote:', getErrorMessage(error))
+      throw new OperatorError('Push to empty remote failed', error as Error)
+    }
+  }
+
   private async getChangedFiles(fromRevision: string, toRevision: string): Promise<string[]> {
     const diffResult = await this.git.diff([`${fromRevision}..${toRevision}`, '--name-only'])
     return diffResult.split('\n').filter((file) => file.trim().length > 0)
@@ -131,6 +167,21 @@ export class GitRepository {
 
   async syncAndAnalyzeChanges(): Promise<{ hasChangesToApply: boolean; applyTeamsOnly: boolean }> {
     try {
+      // Check if remote is empty (migration to new external repo scenario)
+      // If empty, push local content to it first
+      const remoteIsEmpty = await this.isRemoteEmpty()
+      if (remoteIsEmpty) {
+        this.d.info('Detected empty remote repository - pushing local content for migration')
+        await this.pushToEmptyRemote()
+        // After pushing, the remote now has our content, continue with normal flow
+        // Return no changes since we just pushed our current state
+        this._lastRevision = await this.getCurrentRevision()
+        return {
+          hasChangesToApply: false,
+          applyTeamsOnly: false,
+        }
+      }
+
       const previousRevision = this._lastRevision
 
       const newRevision = await this.pull()