fix: Use deepcopy instead of model_dump to copy view

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## [v1.0.2](https://github.com/higlass/higlass-python/compare/v1.0.2...v1.0.1)
 
 - Calculate file pointer hash for track uids for tileset tracks
+- Fix view copy behavior to preserve specific plugin track class vars
 
 ## [v1.0.1](https://github.com/higlass/higlass-python/compare/v1.0.1...v1.0.0)
 

src/higlass/_utils.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import uuid
+from copy import deepcopy
 from typing import Literal, TypeVar, Union
 
 import higlass_schema as hgs
@@ -75,7 +76,7 @@ def ensure_list(x: T | list[T] | None) -> list[T]:
 
 def copy_unique(model: ModelT) -> ModelT:
     """Creates a deep copy of a pydantic BaseModel with new UID."""
-    copy = model.__class__(**model.model_dump())
+    copy = deepcopy(model)
     if hasattr(copy, "uid"):
         setattr(copy, "uid", uid())
     return copy

test/test_api.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from typing import ClassVar, Literal
+
 import pytest
 
 import higlass as hg
@@ -205,3 +207,37 @@ def test_options_mixin():
     assert track is other
     assert track.uid == other.uid
     assert track.options and track.options["foo"] == "bar"
+
+
+def test_plugin_track():
+    """Test that plugin track attributes are maintained after a copy."""
+    some_url = "https://some_url"
+
+    # Here we'll create a custom plugin track.
+    class PileupTrack(hg.PluginTrack):
+        type: Literal["pileup"] = "pileup"
+        plugin_url: ClassVar[str] = some_url
+
+    # Specify the track-specific data
+    pileup_data = {
+        "type": "bam",
+        "url": "https://some_url/sorted.bam",
+        "chromSizesUrl": "https://some_url/sorted.chromsizes.bam",
+        "options": {"maxTileWidth": 30000},
+    }
+
+    # Create and use the custom track
+    pileup_track = PileupTrack(data=pileup_data)
+
+    view = hg.view((pileup_track, "top"))
+    uid1 = view.uid
+    assert view.tracks.top[0].plugin_url == some_url
+
+    # The .domain() function creates a copy of the view. We want to make sure
+    # that the plugin_url attribute of the PluginTrack is maintained
+    view = view.domain(x=[0, 10])
+    uid2 = view.uid
+    assert view.tracks.top[0].plugin_url == some_url
+
+    # Check to make sure the copy behavior changed the uid as expected
+    assert uid1 != uid2