Add wrapped qt package as dependency fix #182

CHANGELOG.md

@@ -1,5 +1,6 @@
 ## [Unreleased] - XXXX-XX-XX
-
+### Changed
+- PySide2 installed by default if wrapped Qt bindings (PyQt5, PySide2) are not found ([#187](https://github.com/cbrnr/mnelab/pull/187) by [Guillaume Dollé](https://github.com/gdolle))
 
 ## [0.6.2] - 2020-10-30
 ### Fixed

setup.py

@@ -4,6 +4,19 @@
 
 from setuptools import setup, find_packages
 from os import path
+from importlib import import_module
+
+
+def optdep(*args, default=None):
+    """Manage alternative dependencies."""
+    for dep in args:
+        try:
+            import_module(dep)
+        except ImportError:
+            continue
+        else:
+            return dep
+    return default
 
 
 here = path.abspath(path.dirname(__file__))
@@ -23,6 +36,9 @@
 with open(path.join(here, "requirements.txt")) as f:
     requires = f.read().splitlines()
 
+qtpkg = optdep("PySide2", "PyQt5", default="PySide2")
+requires.append(qtpkg)
+
 # get extra (optional) requirements
 extras_require = {}
 with open(path.join(here, "requirements-extras.txt")) as f: