fix: allow platform source self-bindings

src/wf_artifacts/validation.py

@@ -24,7 +24,11 @@ def validate_deployment_dependencies(
 
     for logical_source, concrete_source in bindings.items():
         source = sources_by_id.get(logical_source)
-        if source is not None and source.platform:
+        if (
+            source is not None
+            and source.platform
+            and concrete_source != logical_source
+        ):
             diagnostics.append(
                 DependencyDiagnostic(
                     severity=DiagnosticSeverity.ERROR,
@@ -47,7 +51,9 @@ def validate_deployment_dependencies(
         if platform_source is not None and platform_source.platform:
             # Platform sources have fixed ids matching required.logical_source, so
             # sources_by_id can resolve them directly and bindings.get(...) is
-            # intentionally bypassed when choosing bound_source_id.
+            # intentionally bypassed when choosing bound_source_id. A legacy
+            # explicit self-binding such as wf.std -> wf.std is accepted for
+            # compatibility, but it has no effect.
             bound_source_id = required.logical_source
         else:
             bound_source_id = bindings.get(required.logical_source)

tests/artifacts/test_validation.py

@@ -234,6 +234,34 @@ def test_platform_source_requirement_does_not_need_binding() -> None:
     assert diagnostics == []
 
 
+def test_platform_source_accepts_legacy_self_binding() -> None:
+    artifact = artifact_with(
+        required_capability(logical_source="wf.std", capability_name="replace")
+    )
+    deployment = WorkflowDeployment(
+        id="demo.default",
+        artifact_id=artifact.id,
+        artifact_version=artifact.version,
+        bindings={"wf.std": "wf.std"},
+    )
+
+    diagnostics = validate_deployment_dependencies(
+        artifact=artifact,
+        deployment=deployment,
+        sources=[
+            AvailableSource(
+                id="wf.std",
+                platform=True,
+                capabilities={
+                    "replace": AvailableCapability(name="replace", kind="node_spec")
+                },
+            )
+        ],
+    )
+
+    assert diagnostics == []
+
+
 def test_platform_source_rejects_explicit_deployment_binding() -> None:
     artifact = artifact_with(
         required_capability(logical_source="wf.std", capability_name="replace")