Improved error message for infinite update loop & support all Qt libs (…

…#28)

* print name of watcher callback for cyclical dependency

* support all Qt libs and provide better errors in watchers in general

* correct error message

* better error message

* remove test lines

* Update pyproject.toml

* Update __init__.py

* update lockfile

observ/__init__.py

@@ -1,4 +1,4 @@
-__version__ = "0.4.0"
+__version__ = "0.4.1"
 
 
 from .api import *

observ/scheduler.py

@@ -3,6 +3,7 @@
 and should be integrated in the event loop of your choosing.
 """
 from bisect import bisect
+import importlib
 
 
 class Scheduler:
@@ -19,10 +20,16 @@ def register_qt(self):
         """
         Utility function for integration with Qt event loop
         """
-        # Currently only supports PySide6
-        from PySide6.QtCore import QTimer
+        for qt in ("PySide6", "PyQt6", "PySide2", "PyQt5", "PySide", "PyQt4"):
+            try:
+                QtCore = importlib.import_module(f"{qt}.QtCore")
+                break
+            except ImportError:
+                continue
+        else:
+            raise ImportError("Could not import QtCore")
 
-        self.timer = QTimer()
+        self.timer = QtCore.QTimer()
         self.timer.setSingleShot(True)
         self.timer.timeout.connect(scheduler.flush)
         # Set interval to 0 to trigger the timer as soon
@@ -58,9 +65,10 @@ def flush(self):
             if watcher.id in self.has:
                 self.circular[watcher.id] = self.circular.get(watcher.id, 0) + 1
                 if self.circular[watcher.id] > 100:
-                    # TODO: help user to figure out which watcher
-                    # or function this is about
-                    raise RecursionError("Infinite update loop detected")
+                    raise RecursionError(
+                        "Infinite update loop detected in watched"
+                        f" expression {watcher.fn_fqn}"
+                    )
 
             self.index += 1
 

observ/watcher.py

@@ -105,3 +105,7 @@ def depend(self) -> None:
         if Dep.stack:
             for dep in self._deps:
                 dep.depend()
+
+    @property
+    def fn_fqn(self) -> str:
+        return f"{self.fn.__module__}.{self.fn.__qualname__}"