Fix scene-object registration interfering with other COMPAS backends

CHANGELOG.md

@@ -9,10 +9,21 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+* Created `compas_plotter.__all_plugins__`, so COMPAS's plugin manager discovers the
+  `register_scene_objects` factory through the standard `collect_all` path (the
+  same mechanism `compas_viewer` uses).
+
 ### Changed
 
 ### Removed
 
+* Removed Eager, import-time `register_scene_objects()` call in
+  `compas_plotter.scene`, and the `from . import scene` side-effect import in
+  `compas_plotter/__init__.py`. These populated COMPAS's global
+  `ITEM_SCENEOBJECT` at import time, which suppressed the lazy
+  `if not ITEM_SCENEOBJECT` discovery trigger in `compas.scene.context` and left
+  every other backend unregistered.
+
 ## [1.0.0] 2026-07-11
 
 ### Added

src/compas_plotter/__init__.py

@@ -10,10 +10,8 @@
 from .__version__ import __version__
 from .plotter import Plotter
 
-# Importing the scene subpackage triggers registration of the Plotter scene
-# objects. When this package is pip-installed, COMPAS would also discover the
-# @plugin-decorated factory through the entry point; importing here guarantees
-# registration works in editable / non-installed setups as well.
-from . import scene  # noqa: E402,F401
+# COMPAS plugin discovery imports the modules listed here to find the
+# ``@plugin``-decorated ``register_scene_objects`` factory.
+__all_plugins__ = ["compas_plotter.scene"]
 
 __all__ = ["Plotter", "__version__"]

src/compas_plotter/scene/__init__.py

@@ -68,11 +68,6 @@ def register_scene_objects():
     # objects are implemented (Breps additionally need e.g. compas_occ).
 
 
-# Eager registration so that the Plotter works in editable / non-installed setups
-# (where the entry-point-based plugin discovery does not run).
-register_scene_objects()
-
-
 __all__ = [
     "PlotterScene",
     "PlotterSceneObject",

tests/test_plotter.py

@@ -1,3 +1,7 @@
+import subprocess
+import sys
+import textwrap
+
 import matplotlib
 
 matplotlib.use("Agg")
@@ -19,6 +23,8 @@
 from compas.geometry import Sphere
 from compas.geometry import Torus
 from compas.geometry import Vector
+from compas.geometry import Translation
+from compas.scene import Scene
 
 from compas_plotter import Plotter
 from compas_plotter.scene import BoxObject
@@ -33,6 +39,7 @@
 from compas_plotter.scene import PolylineObject
 from compas_plotter.scene import ShapeObject
 from compas_plotter.scene import VectorObject
+from compas_plotter.scene import PlotterScene
 
 
 def test_add_point_returns_pointobject():
@@ -128,9 +135,6 @@ def test_redraw_clears_and_redraws():
 
 
 def test_scene_is_a_compas_scene():
-    from compas.scene import Scene
-
-    from compas_plotter.scene import PlotterScene
 
     plotter = Plotter()
     assert isinstance(plotter.scene, PlotterScene)
@@ -139,7 +143,6 @@ def test_scene_is_a_compas_scene():
 
 
 def test_scene_hierarchy_and_world_transform():
-    from compas.geometry import Translation
 
     plotter = Plotter()
     parent = plotter.add(Point(0, 0, 0))
@@ -217,3 +220,26 @@ def frame(f):
 
     assert obj.vertex_xyz[1][1] == 3.0
     assert obj.vertex_xyz[3][2] == 3.0
+
+
+def test_import_does_not_populate_registry_eagerly():
+    script = textwrap.dedent(
+        """
+        import compas.scene.context as ctx
+        import compas_plotter  # must not register anything on its own
+        assert not ctx.ITEM_SCENEOBJECT, ctx.ITEM_SCENEOBJECT
+
+        # Discovery through the plugin path still finds the Plotter backend and,
+        # critically, the base COMPAS context too.
+        from compas.scene.context import register_scene_objects
+        register_scene_objects()
+        from compas.datastructures import Mesh
+        assert "Plotter" in ctx.ITEM_SCENEOBJECT
+        assert Mesh in ctx.ITEM_SCENEOBJECT["Plotter"]
+        assert Mesh in ctx.ITEM_SCENEOBJECT[None]
+        print("OK")
+        """
+    )
+    result = subprocess.run([sys.executable, "-c", script], capture_output=True, text=True)
+    assert result.returncode == 0, result.stderr
+    assert "OK" in result.stdout