fix(topic): require lowerCamel topic names instead of lower_snake (#2329

)

Breaking change, fixes #2328

Original topic name PR is #1958

backend/controller/pubsub/testdata/go/publisher/publisher.go

@@ -9,7 +9,7 @@ import (
 )
 
 //ftl:export
-var TestTopic = ftl.Topic[PubSubEvent]("test_topic")
+var TestTopic = ftl.Topic[PubSubEvent]("testTopic")
 
 type PubSubEvent struct {
 	Time time.Time
@@ -38,7 +38,7 @@ func PublishOne(ctx context.Context) error {
 }
 
 //ftl:export
-var Topic2 = ftl.Topic[PubSubEvent]("topic_2")
+var Topic2 = ftl.Topic[PubSubEvent]("topic2")
 
 //ftl:verb
 func PublishOneToTopic2(ctx context.Context) error {

go-runtime/compile/external-module-template/.ftl/go/modules/{{ .Module.Name }}/external_module.go.tmpl

@@ -23,7 +23,7 @@ var _ = context.Background
 //
 {{- end}}
 {{- if is "Topic" .}}
-var {{.Name|strippedCamel}} = ftl.Topic[{{type $.Module .Event}}]("{{.Name}}")
+var {{.Name|title}} = ftl.Topic[{{type $.Module .Event}}]("{{.Name}}")
 {{- else if and (is "Enum" .) .IsValueEnum}}
 {{- $enumName := .Name}}
 //ftl:enum

go-runtime/schema/schema_fuzz_test.go

@@ -192,7 +192,7 @@ func (ExportedVariant) exportedTag() {}
 var Topic = ftl.Topic[` + symbol + `]("topic")
 
 //ftl:export
-var ExportedTopic = ftl.Topic[` + symbol + `]("exported_topic")
+var ExportedTopic = ftl.Topic[` + symbol + `]("exportedTopic")
 
 var _ = ftl.Subscription(Topic, "subscription")
 
@@ -334,7 +334,7 @@ module test {
 
   database postgres testDb
 
-  export topic exported_topic {{.TypeName}}
+  export topic exportedTopic {{.TypeName}}
   topic topic {{.TypeName}}
   subscription subscription test.topic
 

go-runtime/schema/schema_test.go

@@ -434,10 +434,10 @@ func TestExtractModulePubSub(t *testing.T) {
 	actual := schema.Normalise(r.Module)
 	expected := `module pubsub {
 		topic payins pubsub.PayinEvent
-		// public_broadcast is a topic that broadcasts payin events to the public.
+		// publicBroadcast is a topic that broadcasts payin events to the public.
 		// out of order with subscription registration to test ordering doesn't matter.
-		export topic public_broadcast pubsub.PayinEvent
-		subscription broadcastSubscription pubsub.public_broadcast
+		export topic publicBroadcast pubsub.PayinEvent
+		subscription broadcastSubscription pubsub.publicBroadcast
 		subscription paymentProcessing pubsub.payins
 
         export data PayinEvent {
@@ -469,7 +469,7 @@ func TestExtractModuleSubscriber(t *testing.T) {
 	assert.Equal(t, nil, r.Errors, "expected no schema errors")
 	actual := schema.Normalise(r.Module)
 	expected := `module subscriber {
-		subscription subscriptionToExternalTopic pubsub.public_broadcast
+		subscription subscriptionToExternalTopic pubsub.publicBroadcast
 
         verb consumesSubscriptionFromExternalTopic(pubsub.PayinEvent) Unit
 		+subscribe subscriptionToExternalTopic

go-runtime/schema/subscription/analyzer.go

@@ -63,7 +63,7 @@ func Extract(pass *analysis.Pass, obj types.Object, node *ast.GenDecl, callExpr
 			common.Errorf(pass, callExpr, "subscription registration must have a topic")
 			return optional.None[*schema.Subscription]()
 		}
-		name := strcase.ToLowerSnake(varName)
+		name := strcase.ToLowerCamel(varName)
 		topicRef = &schema.Ref{
 			Module: moduleIdent.Name,
 			Name:   name,

go-runtime/schema/testdata/pubsub/pubsub.go

@@ -32,11 +32,11 @@ var Payins = ftl.Topic[PayinEvent]("payins")
 
 var _ = ftl.Subscription(PublicBroadcast, "broadcastSubscription")
 
-// public_broadcast is a topic that broadcasts payin events to the public.
+// publicBroadcast is a topic that broadcasts payin events to the public.
 // out of order with subscription registration to test ordering doesn't matter.
 //
 //ftl:export
-var PublicBroadcast = ftl.Topic[PayinEvent]("public_broadcast")
+var PublicBroadcast = ftl.Topic[PayinEvent]("publicBroadcast")
 
 //ftl:verb export
 func Broadcast(ctx context.Context) error {

go-runtime/schema/topic/analyzer.go

@@ -19,7 +19,7 @@ const (
 // Extractor extracts topics.
 var Extractor = common.NewCallDeclExtractor[*schema.Topic]("topic", Extract, ftlTopicFuncPath)
 
-// expects: var NameLiteral = ftl.Topic[EventType]("name_literal")
+// Extract expects: var NameLiteral = ftl.Topic[EventType]("nameLiteral")
 func Extract(pass *analysis.Pass, obj types.Object, node *ast.GenDecl, callExpr *ast.CallExpr,
 	callPath string) optional.Option[*schema.Topic] {
 	indexExpr, ok := callExpr.Fun.(*ast.IndexExpr)
@@ -34,7 +34,7 @@ func Extract(pass *analysis.Pass, obj types.Object, node *ast.GenDecl, callExpr
 	}
 
 	topicName := common.ExtractStringLiteralArg(pass, callExpr, 0)
-	expTopicName := strcase.ToLowerSnake(topicName)
+	expTopicName := strcase.ToLowerCamel(strcase.ToUpperStrippedCamel(topicName))
 	if topicName != expTopicName {
 		common.Errorf(pass, node, "unsupported topic name %q, did you mean to use %q?", topicName, expTopicName)
 		return optional.None[*schema.Topic]()
@@ -43,7 +43,7 @@ func Extract(pass *analysis.Pass, obj types.Object, node *ast.GenDecl, callExpr
 	if len(node.Specs) > 0 {
 		if t, ok := node.Specs[0].(*ast.ValueSpec); ok {
 			varName := t.Names[0].Name
-			expVarName := strcase.ToUpperStrippedCamel(topicName)
+			expVarName := strcase.ToUpperCamel(topicName)
 			if varName != expVarName {
 				common.Errorf(pass, node, "unexpected topic variable name %q, did you mean %q?", varName, expVarName)
 				return optional.None[*schema.Topic]()