Merge pull request #1900 from wkentaro/fix/file-dialog-malformed-json

fix: handle malformed JSON in FileDialogPreview

Author: wkentaro

labelme/widgets/file_dialog_preview.py

@@ -53,9 +53,13 @@ def __init__(self, *args, **kwargs):
 
     def onChange(self, path):
         if path.lower().endswith(".json"):
-            with open(path) as f:
-                data = json.load(f)
-                self.labelPreview.setText(json.dumps(data, indent=4, sort_keys=False))
+            try:
+                with open(path) as f:
+                    data = json.load(f)
+                text = json.dumps(data, indent=4, sort_keys=False)
+            except (json.JSONDecodeError, UnicodeDecodeError) as e:
+                text = f"Cannot preview: {e}"
+            self.labelPreview.setText(text)
             self.labelPreview.label.setAlignment(
                 QtCore.Qt.AlignLeft | QtCore.Qt.AlignTop
             )

tests/conftest.py

@@ -5,6 +5,20 @@
 import pytest
 
 
+def pytest_addoption(parser: pytest.Parser) -> None:
+    parser.addoption(
+        "--show",
+        action="store_true",
+        default=False,
+        help="Show GUI widgets during tests for visual inspection.",
+    )
+
+
+@pytest.fixture()
+def show(request: pytest.FixtureRequest) -> bool:
+    return request.config.getoption("--show", default=False)
+
+
 def _create_annotated_nested(data_path: Path) -> None:
     dst_dir: Path = data_path / "annotated_nested"
     dst_dir.mkdir()

tests/unit/widgets/file_dialog_preview_test.py

@@ -0,0 +1,78 @@
+from __future__ import annotations
+
+import json
+from pathlib import Path
+
+import pytest
+from pytestqt.qtbot import QtBot
+
+from labelme.widgets.file_dialog_preview import FileDialogPreview
+
+
+@pytest.fixture()
+def _file_preview_widget(qtbot: QtBot) -> FileDialogPreview:
+    widget = FileDialogPreview()
+    qtbot.addWidget(widget)
+    return widget
+
+
+def _show_and_wait(widget: FileDialogPreview, qtbot: QtBot) -> None:
+    widget.show()
+    qtbot.waitExposed(widget)
+    qtbot.waitUntil(lambda: not widget.isVisible(), timeout=30_000)
+
+
+@pytest.mark.gui
+def test_onChange_valid_json(
+    _file_preview_widget: FileDialogPreview,
+    tmp_path: Path,
+    qtbot: QtBot,
+    show: bool,
+) -> None:
+    path = tmp_path / "valid.json"
+    path.write_text(json.dumps({"version": "5.0.0", "shapes": []}))
+
+    _file_preview_widget.onChange(str(path))
+
+    assert _file_preview_widget.labelPreview.isHidden() is False
+    assert '"version"' in _file_preview_widget.labelPreview.label.text()
+
+    if show:
+        _show_and_wait(_file_preview_widget, qtbot)
+
+
+@pytest.mark.gui
+@pytest.mark.parametrize(
+    "content_bytes",
+    [
+        b"not valid json {{{{",
+        bytes(range(256)),
+    ],
+    ids=["malformed_json", "binary_file"],
+)
+def test_onChange_bad_json_no_crash(
+    _file_preview_widget: FileDialogPreview,
+    tmp_path: Path,
+    content_bytes: bytes,
+    qtbot: QtBot,
+    show: bool,
+) -> None:
+    path = tmp_path / "bad.json"
+    path.write_bytes(content_bytes)
+
+    _file_preview_widget.onChange(str(path))
+
+    assert _file_preview_widget.labelPreview.isHidden() is False
+    assert "Cannot preview" in _file_preview_widget.labelPreview.label.text()
+
+    if show:
+        _show_and_wait(_file_preview_widget, qtbot)
+
+
+@pytest.mark.gui
+def test_onChange_non_json_non_image_hides_preview(
+    _file_preview_widget: FileDialogPreview,
+) -> None:
+    _file_preview_widget.onChange("/nonexistent/path.txt")
+
+    assert _file_preview_widget.labelPreview.isHidden() is True