Model palette tracks as typed symbol lanes

clips/migrations/0013_palette_track.py

@@ -0,0 +1,45 @@
+"""Schema 4: split animated symbol palettes from the authoring palette.
+
+Before schema 4 a symbol's ``:palette`` leaf value was always a channel. It now
+names the static palette used when that symbol is the viewed root, while the
+old channel is retained as ``:palette-channel`` compatibility data. New edits
+use a real lane symbol referenced by ``:palette-track``.
+"""
+
+from django.db import migrations, models
+
+
+def forwards(apps, schema_editor):
+    Leaf = apps.get_model("clips", "Leaf")
+    Project = apps.get_model("clips", "Project")
+    for leaf in Leaf.objects.filter(path__contains="/symbol/"):
+        parts = leaf.path.split("/")
+        if len(parts) != 4 or parts[2] != "symbol":
+            continue
+        value = leaf.value
+        if not (isinstance(value, list) and value[:1] == ["^ "]):
+            continue
+        out = list(value)
+        changed = False
+        for i in range(1, len(out) - 1, 2):
+            if out[i] == "~:palette" and isinstance(out[i + 1], list):
+                out[i] = "~:palette-channel"
+                changed = True
+        if changed:
+            leaf.value = out
+            leaf.version += 1
+            leaf.save(update_fields=["value", "version"])
+    Project.objects.update(schema_version=4)
+
+
+class Migration(migrations.Migration):
+    dependencies = [("clips", "0012_sound_label")]
+
+    operations = [
+        migrations.AlterField(
+            model_name="project",
+            name="schema_version",
+            field=models.PositiveIntegerField(default=4),
+        ),
+        migrations.RunPython(forwards, migrations.RunPython.noop),
+    ]