Fix event policy check broken after 1.29.0 release (#1641)

policies/compatibility.rego

@@ -48,7 +48,7 @@ baseline_events := [ g |
 ]
 registry_events := [g |
     some g in data.semconv.groups
-    g.type == "events"
+    g.type == "event"
 ]
 registry_event_names := { g.name | some g in registry_events }
 
@@ -236,11 +236,11 @@ deny contains back_comp_violation(description, group_id, attr.name) if {
 # Rule: Detect Removed Metrics
 #
 # This rule checks for stable metrics that existed in the baseline registry
-# but are no longer present in the current registry. Removing attributes
+# but are no longer present in the current registry. Removing metrics
 # is considered a backward compatibility violation.
 #
-# In other words, we do not allow the removal of an attribute once added
-# to the registry. It must exist SOMEWHERE in a group, but may be deprecated.
+# In other words, we do not allow the removal of an metrics once added
+# to semantic conventions. They, however, may be deprecated.
 deny contains back_comp_violation(description, group_id, "") if {
     # Find data we need to enforce
     some metric in baseline_metrics
@@ -366,7 +366,7 @@ deny contains back_comp_violation(description, group_id, "") if {
 # is considered a backward compatibility violation.
 #
 # In other words, we do not allow the removal of a resource once added
-# to the registry. It must exist SOMEWHERE, but may be deprecated.
+# to semantic conventions. They, however, may be deprecated.
 deny contains back_comp_violation(description, group_id, "") if {
     # Find data we need to enforce
     some resource in baseline_resources
@@ -432,11 +432,10 @@ deny contains back_comp_violation(description, group_id, "") if {
 # is considered a backward compatibility violation.
 #
 # In other words, we do not allow the removal of a events once added
-# to the registry. It must exist SOMEWHERE, but may be deprecated.
+# to semantic conventions. They, however, may be deprecated.
 deny contains back_comp_violation(description, group_id, "") if {
     # Find data we need to enforce
     some event in baseline_events
-    event.stability == "stable" # remove after https://github.com/open-telemetry/semantic-conventions/pull/1512 is merged
     # Enforce the policy
     not registry_event_names[event.name]
 

policies_test/compatibility_test.rego

@@ -679,6 +679,30 @@ test_removed_resources if {
     }
 }
 
+# Check that events cannot be removed.
+test_removed_events if {
+	count(deny) > 0 with data.semconv as {
+            "baseline_groups": [{
+                "id": "event.test.missing",
+                "type": "event",
+                "name": "test.missing"
+            }],
+    }
+    count(deny) == 0 with data.semconv as {
+            "baseline_groups": [{
+                "id": "event.test.deprecated",
+                "type": "event",
+                "name": "test.deprecated",
+            }],
+            "groups": [{
+                "id": "event.test.deprecated",
+                "type": "event",
+                "name": "test.deprecated",
+                "deprecated": "use `test` instead",
+            }]
+    }
+}
+
 # Check that Stable resources cannot become unstable
 test_resource_stability_change if {
 	count(deny) > 0 with data.semconv as {