refactor(api): centralise spec group iterator

Co-Authored-By: Virgil <virgil@lethean.io>

cmd/api/spec_groups_iter.go

@@ -12,30 +12,5 @@ import (
 // extra group. It keeps the command paths iterator-backed while preserving the
 // existing ordering guarantees.
 func specGroupsIter(extra goapi.RouteGroup) iter.Seq[goapi.RouteGroup] {
-	return func(yield func(goapi.RouteGroup) bool) {
-		seen := map[string]struct{}{}
-		for group := range goapi.RegisteredSpecGroupsIter() {
-			key := specGroupIterKey(group)
-			seen[key] = struct{}{}
-			if !yield(group) {
-				return
-			}
-		}
-		if extra != nil {
-			if _, ok := seen[specGroupIterKey(extra)]; ok {
-				return
-			}
-			if !yield(extra) {
-				return
-			}
-		}
-	}
-}
-
-func specGroupIterKey(group goapi.RouteGroup) string {
-	if group == nil {
-		return ""
-	}
-
-	return group.Name() + "\x00" + group.BasePath()
+	return goapi.SpecGroupsIter(extra)
 }

spec_registry.go

@@ -90,6 +90,38 @@ func RegisteredSpecGroupsIter() iter.Seq[RouteGroup] {
 	return slices.Values(groups)
 }
 
+// SpecGroupsIter returns the registered spec groups plus one optional extra
+// group, deduplicated by group identity.
+//
+// The iterator snapshots the registry before yielding so callers can range
+// over it without holding the registry lock.
+//
+// Example:
+//
+//	for g := range api.SpecGroupsIter(api.NewToolBridge("/tools")) {
+//		_ = g
+//	}
+func SpecGroupsIter(extra RouteGroup) iter.Seq[RouteGroup] {
+	return func(yield func(RouteGroup) bool) {
+		seen := map[string]struct{}{}
+		for group := range RegisteredSpecGroupsIter() {
+			key := specGroupKey(group)
+			seen[key] = struct{}{}
+			if !yield(group) {
+				return
+			}
+		}
+		if extra != nil {
+			if _, ok := seen[specGroupKey(extra)]; ok {
+				return
+			}
+			if !yield(extra) {
+				return
+			}
+		}
+	}
+}
+
 // ResetSpecGroups clears the package-level spec registry.
 // It is primarily intended for tests that need to isolate global state.
 //

spec_registry_test.go

@@ -110,3 +110,29 @@ func TestRegisterSpecGroupsIter_Good_DeduplicatesAndRegisters(t *testing.T) {
 		t.Fatalf("expected second group to be gamma at /gamma, got %s at %s", registered[1].Name(), registered[1].BasePath())
 	}
 }
+
+func TestSpecGroupsIter_Good_DeduplicatesExtraBridge(t *testing.T) {
+	snapshot := api.RegisteredSpecGroups()
+	api.ResetSpecGroups()
+	t.Cleanup(func() {
+		api.ResetSpecGroups()
+		api.RegisterSpecGroups(snapshot...)
+	})
+
+	first := &specRegistryStubGroup{name: "alpha", basePath: "/alpha"}
+	extra := &specRegistryStubGroup{name: "alpha", basePath: "/alpha"}
+
+	api.RegisterSpecGroups(first)
+
+	var groups []api.RouteGroup
+	for group := range api.SpecGroupsIter(extra) {
+		groups = append(groups, group)
+	}
+
+	if len(groups) != 1 {
+		t.Fatalf("expected deduplicated iterator to return 1 group, got %d", len(groups))
+	}
+	if groups[0].Name() != "alpha" || groups[0].BasePath() != "/alpha" {
+		t.Fatalf("expected alpha at /alpha, got %s at %s", groups[0].Name(), groups[0].BasePath())
+	}
+}