internal, log: remove code for old unsupported go-versions (#28090)

internal/debug/loudpanic.go

@@ -14,9 +14,6 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
 
-//go:build go1.6
-// +build go1.6
-
 package debug
 
 import "runtime/debug"

internal/debug/loudpanic_fallback.go

-// Copyright 2016 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-//go:build !go1.6
-// +build !go1.6
-
-package debug
-
-// LoudPanic panics in a way that gets all goroutine stacks printed on stderr.
-func LoudPanic(x interface{}) {
-	panic(x)
-}

internal/debug/trace.go

@@ -14,9 +14,6 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
 
-//go:build go1.5
-// +build go1.5
-
 package debug
 
 import (

internal/debug/trace_fallback.go

-// Copyright 2016 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-//go:build !go1.5
-// +build !go1.5
-
-// no-op implementation of tracing methods for Go < 1.5.
-
-package debug
-
-import "errors"
-
-func (*HandlerT) StartGoTrace(string) error {
-	return errors.New("tracing is not supported on Go < 1.5")
-}
-
-func (*HandlerT) StopGoTrace() error {
-	return errors.New("tracing is not supported on Go < 1.5")
-}

log/handler.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"reflect"
 	"sync"
+	"sync/atomic"
 
 	"github.com/go-stack/stack"
 )
@@ -354,3 +355,21 @@ func (m muster) FileHandler(path string, fmtr Format) Handler {
 func (m muster) NetHandler(network, addr string, fmtr Format) Handler {
 	return must(NetHandler(network, addr, fmtr))
 }
+
+// swapHandler wraps another handler that may be swapped out
+// dynamically at runtime in a thread-safe fashion.
+type swapHandler struct {
+	handler atomic.Value
+}
+
+func (h *swapHandler) Log(r *Record) error {
+	return (*h.handler.Load().(*Handler)).Log(r)
+}
+
+func (h *swapHandler) Swap(newHandler Handler) {
+	h.handler.Store(&newHandler)
+}
+
+func (h *swapHandler) Get() Handler {
+	return *h.handler.Load().(*Handler)
+}

log/handler_go13.go

-//go:build !go1.4
-// +build !go1.4
-
-package log
-
-import (
-	"sync/atomic"
-	"unsafe"
-)
-
-// swapHandler wraps another handler that may be swapped out
-// dynamically at runtime in a thread-safe fashion.
-type swapHandler struct {
-	handler unsafe.Pointer
-}
-
-func (h *swapHandler) Log(r *Record) error {
-	return h.Get().Log(r)
-}
-
-func (h *swapHandler) Get() Handler {
-	return *(*Handler)(atomic.LoadPointer(&h.handler))
-}
-
-func (h *swapHandler) Swap(newHandler Handler) {
-	atomic.StorePointer(&h.handler, unsafe.Pointer(&newHandler))
-}

log/handler_go14.go

-//go:build go1.4
-// +build go1.4
-
-package log
-
-import "sync/atomic"
-
-// swapHandler wraps another handler that may be swapped out
-// dynamically at runtime in a thread-safe fashion.
-type swapHandler struct {
-	handler atomic.Value
-}
-
-func (h *swapHandler) Log(r *Record) error {
-	return (*h.handler.Load().(*Handler)).Log(r)
-}
-
-func (h *swapHandler) Swap(newHandler Handler) {
-	h.handler.Store(&newHandler)
-}
-
-func (h *swapHandler) Get() Handler {
-	return *h.handler.Load().(*Handler)
-}