log/slog: make examples playable

Fixes #69246

Change-Id: I8e59132980404ee58ba2ca8718dd9f68404fdf8d
GitHub-Last-Rev: f59d3fad2002cda69a24789f2fdd4e9753cede9c
GitHub-Pull-Request: golang/go#69249
Reviewed-on: https://go-review.googlesource.com/c/go/+/610535
Reviewed-by: Sean Liao <sean@liao.dev>
Auto-Submit: Sean Liao <sean@liao.dev>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Jonathan Amsterdam <jba@google.com>

src/log/slog/example_discard_test.go

@@ -6,15 +6,20 @@ package slog_test
 
 import (
 	"log/slog"
-	"log/slog/internal/slogtest"
 	"os"
 )
 
 func Example_discardHandler() {
+	removeTime := func(groups []string, a slog.Attr) slog.Attr {
+		if a.Key == slog.TimeKey && len(groups) == 0 {
+			return slog.Attr{}
+		}
+		return a
+	}
 	// A slog.TextHandler can output log messages.
 	logger1 := slog.New(slog.NewTextHandler(
 		os.Stdout,
-		&slog.HandlerOptions{ReplaceAttr: slogtest.RemoveTime},
+		&slog.HandlerOptions{ReplaceAttr: removeTime},
 	))
 	logger1.Info("message 1")
 

src/log/slog/example_level_handler_test.go

@@ -7,7 +7,6 @@ package slog_test
 import (
 	"context"
 	"log/slog"
-	"log/slog/internal/slogtest"
 	"os"
 )
 
@@ -63,7 +62,13 @@ func (h *LevelHandler) Handler() slog.Handler {
 // Another typical use would be to decrease the log level (to LevelDebug, say)
 // during a part of the program that was suspected of containing a bug.
 func ExampleHandler_levelHandler() {
-	th := slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{ReplaceAttr: slogtest.RemoveTime})
+	removeTime := func(groups []string, a slog.Attr) slog.Attr {
+		if a.Key == slog.TimeKey && len(groups) == 0 {
+			return slog.Attr{}
+		}
+		return a
+	}
+	th := slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{ReplaceAttr: removeTime})
 	logger := slog.New(NewLevelHandler(slog.LevelWarn, th))
 	logger.Info("not printed")
 	logger.Warn("printed")

src/log/slog/example_log_level_test.go

@@ -7,7 +7,6 @@ package slog_test
 import (
 	"log"
 	"log/slog"
-	"log/slog/internal/slogtest"
 	"os"
 )
 
@@ -49,7 +48,13 @@ func ExampleSetLogLoggerLevel_slog() {
 	defer slog.SetLogLoggerLevel(currentLogLevel) // revert changes after the example
 
 	defer slog.SetDefault(slog.Default()) // revert changes after the example
-	slog.SetDefault(slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{ReplaceAttr: slogtest.RemoveTime})))
+	removeTime := func(groups []string, a slog.Attr) slog.Attr {
+		if a.Key == slog.TimeKey && len(groups) == 0 {
+			return slog.Attr{}
+		}
+		return a
+	}
+	slog.SetDefault(slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{ReplaceAttr: removeTime})))
 
 	log.Print("error") // level=ERROR msg=error
 

src/log/slog/example_logvaluer_secret_test.go

@@ -6,7 +6,6 @@ package slog_test
 
 import (
 	"log/slog"
-	"log/slog/internal/slogtest"
 	"os"
 )
 
@@ -23,7 +22,13 @@ func (Token) LogValue() slog.Value {
 // with an alternative representation to avoid revealing secrets.
 func ExampleLogValuer_secret() {
 	t := Token("shhhh!")
-	logger := slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{ReplaceAttr: slogtest.RemoveTime}))
+	removeTime := func(groups []string, a slog.Attr) slog.Attr {
+		if a.Key == slog.TimeKey && len(groups) == 0 {
+			return slog.Attr{}
+		}
+		return a
+	}
+	logger := slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{ReplaceAttr: removeTime}))
 	logger.Info("permission granted", "user", "Perry", "token", t)
 
 	// Output:

src/log/slog/internal/slogtest/slogtest.go

@@ -1,18 +0,0 @@
-// Copyright 2022 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 slogtest contains support functions for testing slog.
-package slogtest
-
-import "log/slog"
-
-// RemoveTime removes the top-level time attribute.
-// It is intended to be used as a ReplaceAttr function,
-// to make example output deterministic.
-func RemoveTime(groups []string, a slog.Attr) slog.Attr {
-	if a.Key == slog.TimeKey && len(groups) == 0 {
-		return slog.Attr{}
-	}
-	return a
-}