3 files changed, 114 insertions, 4 deletions
diff --git a/src/internal/trace/tracev2/events.go b/src/internal/trace/tracev2/events.go
index 778ef8d005..c6dd162a63 100644
--- a/src/internal/trace/tracev2/events.go
+++ b/src/internal/trace/tracev2/events.go
@@ -82,8 +82,14 @@ const (
 
 	// Batch event for an experimental batch with a custom format. Added in Go 1.23.
 	EvExperimentalBatch // start of extra data [experiment ID, generation, M ID, timestamp, batch length, batch data...]
+
+	NumEvents
 )
 
+func (ev EventType) Experimental() bool {
+	return ev > MaxEvent && ev < MaxExperimentalEvent
+}
+
 // Experiments.
 const (
 	// AllocFree is the alloc-free events experiment.
@@ -103,7 +109,7 @@ var experiments = [...]string{
 
 // Experimental events.
 const (
-	_ EventType = 127 + iota
+	MaxEvent EventType = 127 + iota
 
 	// Experimental events for AllocFree.
 
@@ -121,8 +127,12 @@ const (
 	EvGoroutineStack      // stack exists [timestamp, id, order]
 	EvGoroutineStackAlloc // stack alloc [timestamp, id, order]
 	EvGoroutineStackFree  // stack free [timestamp, id]
+
+	MaxExperimentalEvent
 )
 
+const NumExperimentalEvents = MaxExperimentalEvent - MaxEvent
+
 func Specs() []EventSpec {
 	return specs[:]
 }
@@ -158,6 +168,7 @@ var specs = [...]EventSpec{
 		// N.B. There's clearly a timestamp here, but these Events
 		// are special in that they don't appear in the regular
 		// M streams.
+		StackIDs: []int{4},
 	},
 	EvFrequency: {
 		Name: "Frequency",
diff --git a/src/internal/trace/tracev2/events_test.go b/src/internal/trace/tracev2/events_test.go
new file mode 100644
index 0000000000..1f2fbf7610
--- /dev/null
+++ b/src/internal/trace/tracev2/events_test.go
@@ -0,0 +1,98 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package tracev2_test
+
+import (
+	"internal/trace/tracev2"
+	"iter"
+	"regexp"
+	"slices"
+	"strings"
+	"testing"
+)
+
+var argNameRegexp = regexp.MustCompile(`((?P<name>[A-Za-z]+)_)?(?P<type>[A-Za-z]+)`)
+
+func TestSpecs(t *testing.T) {
+	if tracev2.NumEvents <= 0 {
+		t.Fatalf("no trace events?")
+	}
+	if tracev2.MaxExperimentalEvent < tracev2.MaxEvent {
+		t.Fatalf("max experimental event (%d) is < max event (%d)", tracev2.MaxExperimentalEvent, tracev2.MaxEvent)
+	}
+	specs := tracev2.Specs()
+	for ev := range allEvents() {
+		spec := &specs[ev]
+		if spec.Name == "" {
+			t.Errorf("expected event %d to be defined in specs", ev)
+			continue
+		}
+		if spec.IsTimedEvent && spec.Args[0] != "dt" {
+			t.Errorf("%s is a timed event, but its first argument is not 'dt'", spec.Name)
+		}
+		if spec.HasData && spec.Name != "String" && spec.Name != "ExperimentalBatch" {
+			t.Errorf("%s has data, but is not a special kind of event (unsupported, but could be)", spec.Name)
+		}
+		if spec.IsStack && spec.Name != "Stack" {
+			t.Errorf("%s listed as being a stack, but is not the Stack event (unsupported)", spec.Name)
+		}
+		if ev.Experimental() && spec.Experiment == tracev2.NoExperiment {
+			t.Errorf("experimental event %s must have an experiment", spec.Name)
+		}
+
+		// Check arg types.
+		for _, arg := range spec.Args {
+			matches := argNameRegexp.FindStringSubmatch(arg)
+			if len(matches) == 0 {
+				t.Errorf("malformed argument %s for event %s", arg, spec.Name)
+			}
+		}
+
+		// Check stacks.
+		for _, i := range spec.StackIDs {
+			if !strings.HasSuffix(spec.Args[i], "stack") {
+				t.Errorf("stack argument listed at %d in %s, but argument name %s does not imply stack type", i, spec.Name, spec.Args[i])
+			}
+		}
+		for i, arg := range spec.Args {
+			if !strings.HasSuffix(spec.Args[i], "stack") {
+				continue
+			}
+			if !slices.Contains(spec.StackIDs, i) {
+				t.Errorf("found stack argument %s in %s at index %d not listed in StackIDs", arg, spec.Name, i)
+			}
+		}
+
+		// Check strings.
+		for _, i := range spec.StringIDs {
+			if !strings.HasSuffix(spec.Args[i], "string") {
+				t.Errorf("string argument listed at %d in %s, but argument name %s does not imply string type", i, spec.Name, spec.Args[i])
+			}
+		}
+		for i, arg := range spec.Args {
+			if !strings.HasSuffix(spec.Args[i], "string") {
+				continue
+			}
+			if !slices.Contains(spec.StringIDs, i) {
+				t.Errorf("found string argument %s in %s at index %d not listed in StringIDs", arg, spec.Name, i)
+			}
+		}
+	}
+}
+
+func allEvents() iter.Seq[tracev2.EventType] {
+	return func(yield func(tracev2.EventType) bool) {
+		for ev := tracev2.EvNone + 1; ev < tracev2.NumEvents; ev++ {
+			if !yield(ev) {
+				return
+			}
+		}
+		for ev := tracev2.MaxEvent + 1; ev < tracev2.NumExperimentalEvents; ev++ {
+			if !yield(ev) {
+				return
+			}
+		}
+	}
+}
diff --git a/src/internal/trace/tracev2/spec.go b/src/internal/trace/tracev2/spec.go
index 3ea3c59889..af92865781 100644
--- a/src/internal/trace/tracev2/spec.go
+++ b/src/internal/trace/tracev2/spec.go
@@ -22,10 +22,11 @@ type EventSpec struct {
 	// is relied on by the testing framework to type-check arguments.
 	// The structure is:
 	//
-	//     (?P<name>[A-Za-z]+_)?(?P<type>[A-Za-z]+)
+	//     (?P<name>[A-Za-z]+)(_(?P<type>[A-Za-z]+))?
 	//
-	// In sum, it's an optional name followed by a type. If the name
-	// is present, it is separated from the type with an underscore.
+	// In sum, it's a name followed by an optional type.
+	// If the type is present, it is preceded with an underscore.
+	// Arguments without types will be interpreted as just raw uint64s.
 	// The valid argument types and the Go types they map to are listed
 	// in the ArgTypes variable.
 	Args []string