Fix dependency detection in standalone release

CHANGELOG.md

@@ -3,6 +3,9 @@
 - Add dialog for automatic epoch artifact detection with configurable methods ([#558](https://github.com/cbrnr/mnelab/pull/558) by [Fabian Schellander](https://github.com/SchellanderF))
 - Add MNE log messages viewer to history dialog ([#561](https://github.com/cbrnr/mnelab/pull/561) by [Clemens Brunner](https://github.com/cbrnr))
 
+### 🔧 Fixed
+- Fix dependency detection in standalone versions that could have caused some features to not work ([#562](https://github.com/cbrnr/mnelab/pull/562)) by [Clemens Brunner](https://github.com/cbrnr))
+
 ## [1.2.0] · 2026-02-17
 ### ✨ Added
 - Add support for BVRF import via PyBVRF ([#560](https://github.com/cbrnr/mnelab/pull/560) by [Clemens Brunner](https://github.com/cbrnr))

src/mnelab/utils/dependencies.py

@@ -2,7 +2,7 @@
 #
 # License: BSD (3-clause)
 
-from importlib import metadata
+from importlib import import_module, metadata
 
 required = [
     "mne",
@@ -21,14 +21,24 @@
 optional = ["autoreject", "mne-qt-browser", "picard", "sklearn"]
 
 _distribution_names = {
-    "python-picard": "picard",
-    "scikit-learn": "sklearn",
+    "picard": "python-picard",
+    "sklearn": "scikit-learn",
 }
+_import_names = {
+    "pyside6": "PySide6",
+}
+
 have = {}
 for dep in required + optional:
-    distribution_name = {v: k for k, v in _distribution_names.items()}.get(dep, dep)
+    distribution_name = _distribution_names.get(dep, dep)
+    import_name = _import_names.get(dep, dep).replace("-", "_")
     try:
         version = metadata.version(distribution_name)
     except metadata.PackageNotFoundError:
-        version = False
+        try:
+            mod = import_module(import_name)
+        except ImportError:
+            version = False
+        else:
+            version = getattr(mod, "__version__", None) or "unknown"
     have[distribution_name] = version

tests/test_dependencies.py

@@ -0,0 +1,71 @@
+# © MNELAB developers
+#
+# License: BSD (3-clause)
+
+import importlib
+import sys
+from importlib import metadata as importlib_metadata
+from importlib import util as importlib_util
+from pathlib import Path
+from types import SimpleNamespace
+
+
+def _load_dependencies_module(monkeypatch, modules):
+    module_path = (
+        Path(__file__).resolve().parents[1]
+        / "src"
+        / "mnelab"
+        / "utils"
+        / "dependencies.py"
+    )
+
+    def fake_metadata_version(_name):
+        raise importlib_metadata.PackageNotFoundError
+
+    def fake_import_module(name):
+        if name in modules:
+            return modules[name]
+        raise ImportError(name)
+
+    monkeypatch.setattr(importlib_metadata, "version", fake_metadata_version)
+    monkeypatch.setattr(importlib, "import_module", fake_import_module)
+
+    module_name = "mnelab_test_dependencies"
+    sys.modules.pop(module_name, None)
+    spec = importlib_util.spec_from_file_location(module_name, module_path)
+    if spec is None or spec.loader is None:
+        raise RuntimeError("Could not create module spec for dependencies.py")
+    module = importlib_util.module_from_spec(spec)
+    sys.modules[module_name] = module
+    spec.loader.exec_module(module)
+    return module
+
+
+def test_standalone_fallback_detects_importable_dependencies(monkeypatch):
+    modules = {
+        "PySide6": SimpleNamespace(__version__="6.9.4"),
+        "matplotlib": SimpleNamespace(__version__="3.10.0"),
+        "scipy": SimpleNamespace(__version__="1.14.1"),
+        "pyxdf": SimpleNamespace(__version__="1.16.0"),
+        "pybvrf": SimpleNamespace(__version__="0.1.1"),
+        "black": SimpleNamespace(__version__="25.0.0"),
+        "onnx": SimpleNamespace(__version__="1.20.0"),
+        "picard": SimpleNamespace(__version__="0.8.0"),
+    }
+
+    dependencies = _load_dependencies_module(monkeypatch, modules)
+
+    assert dependencies.have["pyside6"] == "6.9.4"
+    assert dependencies.have["matplotlib"] == "3.10.0"
+    assert dependencies.have["scipy"] == "1.14.1"
+    assert dependencies.have["pyxdf"] == "1.16.0"
+    assert dependencies.have["pybvrf"] == "0.1.1"
+    assert dependencies.have["black"] == "25.0.0"
+    assert dependencies.have["onnx"] == "1.20.0"
+    assert dependencies.have["python-picard"] == "0.8.0"
+
+
+def test_standalone_fallback_keeps_false_for_missing_import(monkeypatch):
+    dependencies = _load_dependencies_module(monkeypatch, modules={})
+
+    assert dependencies.have["pyside6"] is False