fix(canonical-formats): honor seller Retina precedence

Author: bokelley

src/adcp/canonical_formats/v1_to_v2.py

@@ -18,7 +18,9 @@
    :class:`CanonicalProjectionReference` carrying ``kind``,
    ``asset_source``, and ``slots_override[]``. Highest priority on
    the v1→v2 path. Registry-published ``parameters`` for a matching
-   glob still fill in anything the seller didn't restate.
+   glob still fill neutral parameters the seller didn't restate, but
+   registry slot and pixel-density defaults never merge into the
+   seller-authored declaration.
 2. **Registry glob match** (registry step 3). Look up
    ``v1_format.format_id.id`` in the bundled registry's
    ``format_id_glob`` entries. The bundled 3.1.10 registry includes
@@ -65,6 +67,12 @@
 
 FormatId = LegacyFormatId
 
+_SELLER_AUTHORITATIVE_PARAM_KEYS = {
+    "pixel_ratios",
+    "required_pixel_ratios",
+    "slots",
+}
+
 
 @dataclass
 class V1ToV2Projection:
@@ -267,10 +275,10 @@ def project_v1_format_to_declaration(
     # seller annotations can still pick up registry-published default
     # ``parameters`` without forcing the seller to restate them on the v1
     # file. Step 1 (seller annotation) overrides ``kind`` /
-    # ``slots_override`` / ``asset_source`` but does NOT clobber the
-    # registry's parametric defaults — that would lose every parameter
-    # a registry glob carries (e.g., ``vast_version``, dimensions) when
-    # a seller annotates only ``{kind: video_vast}``.
+    # ``slots_override`` / ``asset_source``. Neutral registry parameters
+    # such as dimensions still fill omitted values, but seller-authored
+    # declarations must not inherit registry slot or pixel-density
+    # contracts.
     registry_params: dict[str, Any] = {}
     registry_kind: CanonicalFormatKind | None = None
     for mapping in registry.mappings:
@@ -283,15 +291,21 @@ def project_v1_format_to_declaration(
 
     # --- Step 1 (registry resolution-order step 2): seller-asserted
     # ``canonical`` annotation on the v1 file. Annotation wins on
-    # ``kind`` + ``asset_source`` + ``slots_override``; registry
-    # parameters fill in anything the seller didn't restate.
+    # ``kind`` + ``asset_source`` + ``slots_override``; neutral registry
+    # parameters fill omitted values without importing registry slot or
+    # pixel-density contracts.
     annotation = _v1_canonical_annotation(v1_format)
     if annotation is not None:
+        seller_params = {
+            key: value
+            for key, value in registry_params.items()
+            if key not in _SELLER_AUTHORITATIVE_PARAM_KEYS
+        }
         return V1ToV2Projection(
             declaration=_build_declaration(
                 kind=annotation.kind,
                 v1_format_id=fid,
-                params=registry_params,
+                params=seller_params,
                 canonical_ref=annotation,
             )
         )

tests/test_canonical_formats_v1_to_v2.py

@@ -80,6 +80,59 @@ def test_slots_override_threads_into_params() -> None:
     assert slots[0]["asset_group_id"] == "image_main"
 
 
+def test_seller_slots_override_registry_retina_slot_contract() -> None:
+    v1 = {
+        "format_id": {
+            "agent_url": "https://creative.adcontextprotocol.org",
+            "id": "display_300x250_image_1x_2x",
+        },
+        "canonical": {
+            "kind": "image",
+            "slots_override": [
+                {
+                    "asset_group_id": "seller_image",
+                    "asset_type": "image",
+                    "required": True,
+                }
+            ],
+        },
+    }
+
+    result = project_v1_format_to_declaration(v1)
+
+    assert result.declaration is not None
+    assert result.declaration.params == {
+        "width": 300,
+        "height": 250,
+        "slots": [
+            {
+                "asset_group_id": "seller_image",
+                "asset_type": "image",
+                "required": True,
+                "consumed_for_production": True,
+            }
+        ],
+    }
+    assert result.advisories == []
+
+
+def test_seller_kind_does_not_inherit_registry_retina_contract() -> None:
+    v1 = {
+        "format_id": {
+            "agent_url": "https://creative.adcontextprotocol.org",
+            "id": "display_300x250_image_1x_2x",
+        },
+        "canonical": {"kind": "html5"},
+    }
+
+    result = project_v1_format_to_declaration(v1)
+
+    assert result.declaration is not None
+    assert result.declaration.format_kind is CanonicalFormatKind.html5
+    assert result.declaration.params == {"width": 300, "height": 250}
+    assert result.advisories == []
+
+
 # ---------------------------------------------------------------------------
 # Step 2 — registry glob match (no explicit canonical)
 # ---------------------------------------------------------------------------