fix: file handling when directory does not exist (#2206)

Allows users to create files in subdirectories that don't yet exist by
creating them; previously, this failed in an unintuitive way.

marimo/_server/file_manager.py

@@ -2,6 +2,7 @@
 from __future__ import annotations
 
 import os
+import pathlib
 from typing import Any, Dict, Optional
 
 from marimo import _loggers
@@ -58,11 +59,18 @@ def _assert_path_is_the_same(self, filename: str) -> None:
                 detail="Save handler cannot rename files.",
             )
 
+    def _create_parent_directories(self, filename: str) -> None:
+        try:
+            pathlib.Path(filename).parent.mkdir(parents=True, exist_ok=True)
+        except Exception:
+            pass
+
     def _create_file(
         self,
         filename: str,
         contents: str = "",
     ) -> None:
+        self._create_parent_directories(filename)
         try:
             with open(filename, "w", encoding="utf-8") as f:
                 f.write(contents)
@@ -74,6 +82,7 @@ def _create_file(
 
     def _rename_file(self, new_filename: str) -> None:
         assert self.filename is not None
+        self._create_parent_directories(new_filename)
         try:
             os.rename(self.filename, new_filename)
         except Exception as err:

marimo/_server/files/os_file_system.py

@@ -32,31 +32,34 @@ def get_root(self) -> str:
     def list_files(self, path: str) -> List[FileInfo]:
         files: List[FileInfo] = []
         folders: List[FileInfo] = []
-        with os.scandir(path) as it:
-            for entry in it:
-                if entry.name in IGNORE_LIST:
-                    continue
-                try:
-                    is_directory = entry.is_dir()
-                    entry_stat = entry.stat()
-                except OSError:
-                    # do not include files that fail to read
-                    # (e.g. recursive/broken symlinks)
-                    continue
-
-                info = FileInfo(
-                    id=entry.path,
-                    path=entry.path,
-                    name=entry.name,
-                    is_directory=is_directory,
-                    is_marimo_file=not is_directory
-                    and self._is_marimo_file(entry.path),
-                    last_modified=entry_stat.st_mtime,
-                )
-                if is_directory:
-                    folders.append(info)
-                else:
-                    files.append(info)
+        try:
+            with os.scandir(path) as it:
+                for entry in it:
+                    if entry.name in IGNORE_LIST:
+                        continue
+                    try:
+                        is_directory = entry.is_dir()
+                        entry_stat = entry.stat()
+                    except OSError:
+                        # do not include files that fail to read
+                        # (e.g. recursive/broken symlinks)
+                        continue
+
+                    info = FileInfo(
+                        id=entry.path,
+                        path=entry.path,
+                        name=entry.name,
+                        is_directory=is_directory,
+                        is_marimo_file=not is_directory
+                        and self._is_marimo_file(entry.path),
+                        last_modified=entry_stat.st_mtime,
+                    )
+                    if is_directory:
+                        folders.append(info)
+                    else:
+                        files.append(info)
+        except OSError:
+            pass
 
         return sorted(folders, key=natural_sort_file) + sorted(
             files, key=natural_sort_file

tests/_server/test_file_manager.py

@@ -106,6 +106,24 @@ def test_rename_create_new_file(app_file_manager: AppFileManager) -> None:
         os.remove(new_filename)
 
 
+def test_rename_create_new_directory_file(
+    app_file_manager: AppFileManager,
+) -> None:
+    app_file_manager.filename = None
+    new_directory = "new_directory"
+    new_filename = os.path.join(new_directory, "new_file.py")
+    if os.path.exists(new_filename):
+        os.remove(new_filename)
+    if os.path.exists(new_directory):
+        os.rmdir(new_directory)
+    try:
+        app_file_manager.rename(new_filename)
+        assert os.path.exists(new_filename)
+    finally:
+        os.remove(new_filename)
+        os.rmdir(new_directory)
+
+
 def test_rename_different_filetype(app_file_manager: AppFileManager) -> None:
     initial_filename = app_file_manager.filename
     assert initial_filename