Fix path resolution for absolute workspace paths

Updated the Editor's resolve method to correctly handle absolute paths that start with the workspace root, preventing duplication of the root in resolved paths. Added a test to verify correct behavior when creating files with absolute paths within the workspace.

Author: threepointone

packages/sandbox/src/openai/index.ts

@@ -403,8 +403,16 @@ export class Editor implements OpenAIEeditor {
   }
 
   private resolve(relativePath: string): string {
+    // If the path already starts with the root, strip it to get the relative part
+    let pathToProcess = relativePath;
+    if (relativePath.startsWith(this.root)) {
+      pathToProcess = relativePath.slice(this.root.length);
+      // Remove leading slash if present after stripping root
+      pathToProcess = pathToProcess.replace(/^\//, '');
+    }
+
     // Remove leading ./ or / if present, then join with root
-    const normalized = relativePath.replace(/^\.\//, '').replace(/^\//, '');
+    const normalized = pathToProcess.replace(/^\.\//, '').replace(/^\//, '');
     const resolved = normalized ? `${this.root}/${normalized}` : this.root;
 
     // Normalize path separators first

packages/sandbox/tests/openai-shell-editor.test.ts

@@ -403,5 +403,32 @@ describe('Editor', () => {
       );
       expect(mockSandbox.writeFile).not.toHaveBeenCalled();
     });
+
+    it('should handle absolute paths within workspace', async () => {
+      applyDiffMock.mockReturnValueOnce('content');
+
+      const mockSandbox: MockSandbox = {
+        mkdir: vi.fn().mockResolvedValue(undefined),
+        writeFile: vi.fn().mockResolvedValue(undefined)
+      };
+
+      const editor = new Editor(
+        mockSandbox as unknown as Sandbox,
+        '/workspace'
+      );
+      const operation = {
+        type: 'create_file',
+        path: '/workspace/file.txt',
+        diff: 'content'
+      } as Extract<ApplyPatchOperation, { type: 'create_file' }>;
+
+      await editor.createFile(operation);
+
+      expect(mockSandbox.writeFile).toHaveBeenCalledWith(
+        '/workspace/file.txt', // Not /workspace/workspace/file.txt
+        'content',
+        { encoding: 'utf-8' }
+      );
+    });
   });
 });