runtime/debug: eliminate temporary variadicity from SetCrashOutput

Updates #67182

Change-Id: I33fc8c515f4a9d120262ba30f61aea80ede5e9f8
Reviewed-on: https://go-review.googlesource.com/c/go/+/585420
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Austin Clements <austin@google.com>

Author: adonovan

api/next/42888.txt

@@ -1,2 +1,2 @@
 pkg runtime/debug, type CrashOptions struct #67182
-pkg runtime/debug, func SetCrashOutput(*os.File, ...CrashOptions) error #42888
+pkg runtime/debug, func SetCrashOutput(*os.File, CrashOptions) error #42888

src/runtime/debug/example_monitor_test.go

@@ -91,7 +91,7 @@ func monitor() {
 	if err != nil {
 		log.Fatalf("StdinPipe: %v", err)
 	}
-	debug.SetCrashOutput(pipe.(*os.File)) // (this conversion is safe)
+	debug.SetCrashOutput(pipe.(*os.File), debug.CrashOptions{}) // (this conversion is safe)
 	if err := cmd.Start(); err != nil {
 		log.Fatalf("can't start monitor: %v", err)
 	}

src/runtime/debug/stack.go

@@ -46,14 +46,7 @@ type CrashOptions struct {
 // To disable this additional crash output, call SetCrashOutput(nil).
 // If called concurrently with a crash, some in-progress output may be written
 // to the old file even after an overriding SetCrashOutput returns.
-//
-// TODO(adonovan): the variadic ... is a short-term measure to avoid
-// breaking the call in x/telemetry; it will be removed before the
-// go1.23 freeze.
-func SetCrashOutput(f *os.File, opts ...CrashOptions) error {
-	if len(opts) > 1 {
-		panic("supply at most 1 CrashOptions")
-	}
+func SetCrashOutput(f *os.File, opts CrashOptions) error {
 	fd := ^uintptr(0)
 	if f != nil {
 		// The runtime will write to this file descriptor from

src/runtime/debug/stack_test.go

@@ -13,6 +13,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"runtime"
+	"runtime/debug"
 	. "runtime/debug"
 	"strings"
 	"testing"
@@ -29,7 +30,7 @@ func TestMain(m *testing.M) {
 		if err != nil {
 			log.Fatal(err)
 		}
-		if err := SetCrashOutput(f); err != nil {
+		if err := SetCrashOutput(f, debug.CrashOptions{}); err != nil {
 			log.Fatal(err) // e.g. EMFILE
 		}
 		println("hello")

src/runtime/traceback_system_test.go

@@ -28,7 +28,7 @@ func crash() {
 	// Ensure that we get pc=0x%x values in the traceback.
 	debug.SetTraceback("system")
 	writeSentinel(os.Stdout)
-	debug.SetCrashOutput(os.Stdout)
+	debug.SetCrashOutput(os.Stdout, debug.CrashOptions{})
 
 	go func() {
 		// This call is typically inlined.