From 0f2b4d713bfaa135f5c0d36c8a8c2d2a040c9853 Mon Sep 17 00:00:00 2001
From: Jan Petykiewicz <jan@mpxd.net>
Date: Wed, 1 Apr 2026 23:34:40 -0700
Subject: [PATCH] [Pattern] make plug/place atomic wrt. annotation conflicts

---
 masque/pattern.py           |  8 ++++++++
 masque/test/test_pattern.py | 30 ++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/masque/pattern.py b/masque/pattern.py
index b670493..9586140 100644
--- a/masque/pattern.py
+++ b/masque/pattern.py
@@ -1387,6 +1387,10 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
             if append:
                 if isinstance(other, Abstract):
                     raise PatternError('Must provide a full `Pattern` (not an `Abstract`) when appending!')
+                if other.annotations is not None and self.annotations is not None:
+                    annotation_conflicts = set(self.annotations.keys()) & set(other.annotations.keys())
+                    if annotation_conflicts:
+                        raise PatternError(f'Annotation keys overlap: {annotation_conflicts}')
             else:
                 if isinstance(other, Pattern):
                     raise PatternError('Must provide an `Abstract` (not a `Pattern`) when creating a reference. '
@@ -1562,6 +1566,10 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
             if append:
                 if isinstance(other, Abstract):
                     raise PatternError('Must provide a full `Pattern` (not an `Abstract`) when appending!')
+                if other.annotations is not None and self.annotations is not None:
+                    annotation_conflicts = set(self.annotations.keys()) & set(other.annotations.keys())
+                    if annotation_conflicts:
+                        raise PatternError(f'Annotation keys overlap: {annotation_conflicts}')
             elif isinstance(other, Pattern):
                 raise PatternError('Must provide an `Abstract` (not a `Pattern`) when creating a reference. '
                                    'Use `append=True` if you intended to append the full geometry.')
diff --git a/masque/test/test_pattern.py b/masque/test/test_pattern.py
index 6048bf1..c100079 100644
--- a/masque/test/test_pattern.py
+++ b/masque/test/test_pattern.py
@@ -148,6 +148,17 @@ def test_pattern_place_append_requires_pattern_atomically() -> None:
     assert not parent.ports
 
 
+def test_pattern_place_append_annotation_conflict_is_atomic() -> None:
+    parent = Pattern(annotations={"k": [1]})
+    child = Pattern(annotations={"k": [2]}, ports={"A": Port((1, 2), 0)})
+
+    with pytest.raises(PatternError, match="Annotation keys overlap"):
+        parent.place(child, append=True)
+
+    assert not parent.ports
+    assert parent.annotations == {"k": [1]}
+
+
 def test_pattern_interface() -> None:
     source = Pattern()
     source.ports["A"] = Port((10, 20), 0, ptype="test")
@@ -192,6 +203,25 @@ def test_pattern_plug_requires_abstract_for_reference_atomically() -> None:
     assert set(parent.ports) == {"X"}
 
 
+def test_pattern_plug_append_annotation_conflict_is_atomic() -> None:
+    parent = Pattern(
+        annotations={"k": [1]},
+        ports={"X": Port((0, 0), 0), "Q": Port((9, 9), 0)},
+        )
+    child = Pattern(
+        annotations={"k": [2]},
+        ports={"A": Port((0, 0), pi), "B": Port((5, 0), 0)},
+        )
+
+    with pytest.raises(PatternError, match="Annotation keys overlap"):
+        parent.plug(child, {"X": "A"}, map_out={"B": "Y"}, append=True)
+
+    assert set(parent.ports) == {"X", "Q"}
+    assert_allclose(parent.ports["X"].offset, (0, 0))
+    assert_allclose(parent.ports["Q"].offset, (9, 9))
+    assert parent.annotations == {"k": [1]}
+
+
 def test_pattern_append_port_conflict_is_atomic() -> None:
     pat1 = Pattern()
     pat1.ports["A"] = Port((0, 0), 0)