Convert outbound links to pascal case

Author: dandavison

temporalio/nexus/_operation_context.py

@@ -514,14 +514,7 @@ def _workflow_event_to_nexus_link(
     workflow_id = urllib.parse.quote(workflow_event.workflow_id)
     run_id = urllib.parse.quote(workflow_event.run_id)
     path = f"/namespaces/{namespace}/workflows/{workflow_id}/{run_id}/history"
-    query_params = urllib.parse.urlencode(
-        {
-            "eventType": temporalio.api.enums.v1.EventType.Name(
-                workflow_event.event_ref.event_type
-            ),
-            "referenceType": "EventReference",
-        }
-    )
+    query_params = _query_params_from_event_reference(workflow_event.event_ref)
     return nexusrpc.Link(
         url=urllib.parse.urlunparse((scheme, "", path, "", query_params, "")),
         type=workflow_event.DESCRIPTOR.full_name,
@@ -555,6 +548,19 @@ def _nexus_link_to_workflow_event(
     )
 
 
+def _query_params_from_event_reference(
+    event_ref: temporalio.api.common.v1.Link.WorkflowEvent.EventReference,
+) -> str:
+    event_type_name = temporalio.api.enums.v1.EventType.Name(event_ref.event_type)
+    if event_type_name.startswith("EVENT_TYPE_"):
+        event_type_name = _constant_case_to_pascal_case(
+            event_type_name.removeprefix("EVENT_TYPE_")
+        )
+    return urllib.parse.urlencode(
+        {"eventType": event_type_name, "referenceType": "EventReference"}
+    )
+
+
 def _event_reference_from_query_params(
     raw_query_params: str,
 ) -> temporalio.api.common.v1.Link.WorkflowEvent.EventReference:
@@ -596,6 +602,13 @@ def _event_reference_from_query_params(
     )
 
 
+def _constant_case_to_pascal_case(s: str) -> str:
+    """
+    Convert a CONSTANT_CASE string to PascalCase.
+    """
+    return re.sub(r"(\b|_)([a-z])", lambda m: m.groups()[1].upper(), s.lower())
+
+
 def _pascal_case_to_constant_case(s: str) -> str:
     """
     Convert a PascalCase string to CONSTANT_CASE.

tests/nexus/test_workflow_caller.py

@@ -1277,9 +1277,19 @@ async def test_workflow_run_operation_overloads(
 
 
 def test_link_conversion_utilities():
-    pc2cc = temporalio.nexus._operation_context._pascal_case_to_constant_case
-    assert pc2cc("") == ""
-    assert pc2cc("A") == "A"
-    assert pc2cc("a") == "A"
-    assert pc2cc("AbCd") == "AB_CD"
-    assert pc2cc("NexusOperationScheduled") == "NEXUS_OPERATION_SCHEDULED"
+    p2c = temporalio.nexus._operation_context._pascal_case_to_constant_case
+    c2p = temporalio.nexus._operation_context._constant_case_to_pascal_case
+
+    for p, c in [
+        ("", ""),
+        ("A", "A"),
+        ("Ab", "AB"),
+        ("AbCd", "AB_CD"),
+        ("AbCddE", "AB_CDD_E"),
+        ("NexusOperationScheduled", "NEXUS_OPERATION_SCHEDULED"),
+    ]:
+        assert p2c(p) == c
+        assert c2p(c) == p
+
+    assert p2c("a") == "A"
+    assert c2p("A") == "A"