Don't clear files in the state on execution start

src/backend/workers/python/papyros/papyros.py

@@ -160,7 +160,7 @@ def _flush_open_files(self):
                     pass
         self._tracked_files -= closed
 
-    def _emit_created_files(self, emit_empty=False):
+    def _emit_created_files(self):
         with self._without_file_tracking():
             cwd = os.getcwd()
             result = {}
@@ -186,11 +186,10 @@ def _emit_created_files(self, emit_empty=False):
             except Exception:
                 return
             snapshot = json.dumps(result, sort_keys=True)
-            if snapshot == self._last_emitted_snapshot and not emit_empty:
+            if snapshot == self._last_emitted_snapshot:
                 return
             self._last_emitted_snapshot = snapshot
-            if result or emit_empty:
-                self.callback("files", data=snapshot, contentType="text/json")
+            self.callback("files", data=snapshot, contentType="text/json")
 
     @contextmanager
     def _execute_context(self):
@@ -232,7 +231,7 @@ async def run_async(self, source_code, mode="exec", top_level_await=True):
                         from tracer import JSONTracer
                         def frame_callback(frame):
                             self._flush_open_files()
-                            self._emit_created_files(emit_empty=True)
+                            self._emit_created_files()
                             self.callback("frame", data=frame, contentType="application/json")
 
                         result = JSONTracer(frame_callback=frame_callback, module_name=MODULE_NAME).runscript(source_code)

src/frontend/state/InputOutput.ts

@@ -232,7 +232,6 @@ export class InputOutput extends State {
         this.output = [];
         this.prompt = "";
         this.awaitingInput = false;
-        this.files = [];
         this.activeEditorTab = CODE_TAB;
     }
 }

test/__tests__/state/Files.test.ts

@@ -1,7 +1,7 @@
 import { Papyros } from "../../../src/frontend/state/Papyros";
 import { expect, it, describe } from "vitest";
 import { ProgrammingLanguage } from "../../../src/ProgrammingLanguage";
-import { waitForFiles, waitForPapyrosReady, waitForInputReady, waitForOutput } from "../../helpers";
+import { waitForFiles, waitForPapyrosReady, waitForInputReady, waitForOutput, waitForAwaitingInput } from "../../helpers";
 import { isValidFileName } from "../../../src/util/Util";
 
 describe("isValidFileName", () => {
@@ -117,6 +117,47 @@ raise ValueError("intentional error")
         expect(papyros.io.files[0].content).toBe("before crash");
     });
 
+    it("files from previous run persist while awaiting input in next run", async () => {
+        const papyros = new Papyros();
+        await papyros.launch();
+        papyros.runner.programmingLanguage = ProgrammingLanguage.Python;
+        papyros.runner.code = `open("persist.txt", "w").write("hello")`;
+        await waitForInputReady();
+        await papyros.runner.start();
+        await waitForFiles(papyros, 1);
+        expect(papyros.io.files.length).toBe(1);
+        expect(papyros.io.files[0].name).toBe("persist.txt");
+
+        papyros.runner.code = `x = input("name?")`;
+        await waitForPapyrosReady(papyros);
+        void papyros.runner.start();
+        await waitForAwaitingInput(papyros);
+        expect(papyros.io.files.length).toBe(1);
+        expect(papyros.io.files[0].name).toBe("persist.txt");
+
+        papyros.io.provideInput("test");
+        await waitForPapyrosReady(papyros);
+        expect(papyros.io.files.length).toBe(1);
+        expect(papyros.io.files[0].name).toBe("persist.txt");
+    });
+
+    it("files from previous run are cleared when next run deletes them", async () => {
+        const papyros = new Papyros();
+        await papyros.launch();
+        papyros.runner.programmingLanguage = ProgrammingLanguage.Python;
+        papyros.runner.code = `open("temp.txt", "w").write("hello")`;
+        await waitForInputReady();
+        await papyros.runner.start();
+        await waitForFiles(papyros, 1);
+        expect(papyros.io.files.length).toBe(1);
+        expect(papyros.io.files[0].name).toBe("temp.txt");
+
+        papyros.runner.code = `import os; os.remove("temp.txt")`;
+        await papyros.runner.start();
+        await waitForPapyrosReady(papyros);
+        expect(papyros.io.files.length).toBe(0);
+    });
+
     it("updateFileContent updates the in-memory content of an existing file", async () => {
         const papyros = new Papyros();
         await papyros.launch();