fix: prevent FileBrowser from using relative paths for directory sync

maartenbreddels · claude · maartenbreddels · commit 7be73e88ba82 · 2026-01-13T12:35:22.000+01:00
When `selected` was set to a relative path after previously being set to
an absolute path, the `sync_directory_from_selected` function would
incorrectly resolve the relative path against the process CWD instead of
the FileBrowser's current directory, leading to FileNotFoundError.

Co-Authored-By: Claude Opus 4.5 &lt;noreply@anthropic.com&gt;
diff --git a/solara/components/file_browser.py b/solara/components/file_browser.py
@@ -148,9 +148,13 @@ def sync_directory_from_selected():
             # if we select a file, we need to make sure the directory is correct
             # NOTE: although we expect a Path, abuse might make it a string
             if isinstance(selected_private, Path):
-                # Note that we do not call .resolve() before using .parent, otherwise /some/path/.. will
-                # set the current directory to /, moving up two levels.
-                current_dir.value = selected_private.parent.resolve()
+                # Only sync directory from selected if the path is absolute.
+                # Relative paths would resolve against the process CWD, not the
+                # current directory shown in the FileBrowser, leading to incorrect paths.
+                if selected_private.is_absolute():
+                    # Note that we do not call .resolve() before using .parent, otherwise /some/path/.. will
+                    # set the current directory to /, moving up two levels.
+                    current_dir.value = selected_private.parent.resolve()
 
     solara.use_effect(sync_directory_from_selected, [selected_private])
 
diff --git a/tests/unit/file_browser_test.py b/tests/unit/file_browser_test.py
@@ -445,3 +445,43 @@ def on_files_change(change):
     assert "file2.txt" not in new_files
 
     rc.close()
+
+
+def test_file_browser_selected_relative_path_after_full_path(tmpdir: Path):
+    """Test that FileBrowser handles setting selected to a relative path after a full path.
+
+    Regression test for issue where:
+    1. User sets selected to a full path like /some/path/subdir/file.txt
+    2. User then sets selected to a relative path like subdir/file.txt
+    3. The current_dir would incorrectly become /some/path/subdir/subdir
+       because the relative path's parent was appended to the existing directory.
+    """
+    tmpdir = Path(tmpdir)
+    subdir = tmpdir / "subdir"
+    subdir.mkdir()
+    (subdir / "file.txt").write_text("content")
+
+    selected = solara.reactive(cast(Optional[Path], None))
+
+    @solara.component
+    def Test():
+        return solara.FileBrowser(tmpdir, selected=selected, can_select=True)
+
+    div, rc = solara.render_fixed(Test(), handle_error=False)
+
+    # First, set selected to a full path
+    full_path = subdir / "file.txt"
+    selected.value = full_path
+
+    # Verify we're now in the subdir
+    current_dir_text = div.children[0].children[0]
+    assert str(subdir) in current_dir_text
+
+    # Now set selected to a relative path (simulating user setting selected to "subdir/file.txt")
+    # This should work and stay in the same subdir, not create /subdir/subdir
+    relative_path = Path("subdir") / "file.txt"
+    selected.value = relative_path
+
+    # This should not raise FileNotFoundError
+    # The current_dir should resolve relative to cwd, not to the previous current_dir
+    rc.close()
