lib/time: update to 2022g/2022g

Commit generated by update.bash.

For #22487.

Change-Id: I6a995a3baea7c511b9bd5155f81d8b8e2cdff09d
Reviewed-on: https://go-review.googlesource.com/c/go/+/455356
Reviewed-by: Heschi Kreinick <heschi@google.com>
Run-TryBot: Russ Cox <rsc@golang.org>
Auto-Submit: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>

3 files changed, 153 insertions, 11 deletions

diff --git a/lib/time/mkzip.go b/lib/time/mkzip.go
new file mode 100644
index 0000000000..3920b11b6c
--- /dev/null
+++ b/lib/time/mkzip.go
@@ -0,0 +1,94 @@
+// 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.
+
+//go:build ignore
+
+// Mkzip writes a zoneinfo.zip with the content of the current directory
+// and its subdirectories, with no compression, suitable for package time.
+//
+// Usage:
+//
+//	go run ../../mkzip.go ../../zoneinfo.zip
+//
+// We use this program instead of 'zip -0 -r ../../zoneinfo.zip *' to get
+// a reproducible generator that does not depend on which version of the
+// external zip tool is used or the ordering of file names in a directory
+// or the current time.
+package main
+
+import (
+	"archive/zip"
+	"bytes"
+	"flag"
+	"fmt"
+	"hash/crc32"
+	"io/fs"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+func usage() {
+	fmt.Fprintf(os.Stderr, "usage: go run mkzip.go ../../zoneinfo.zip\n")
+	os.Exit(2)
+}
+
+func main() {
+	log.SetPrefix("mkzip: ")
+	log.SetFlags(0)
+	flag.Usage = usage
+	flag.Parse()
+	args := flag.Args()
+	if len(args) != 1 || !strings.HasSuffix(args[0], ".zip") {
+		usage()
+	}
+
+	var zb bytes.Buffer
+	zw := zip.NewWriter(&zb)
+	seen := make(map[string]bool)
+	err := filepath.WalkDir(".", func(path string, d fs.DirEntry, err error) error {
+		if d.IsDir() {
+			return nil
+		}
+		data, err := os.ReadFile(path)
+		if err != nil {
+			log.Fatal(err)
+		}
+		if strings.HasSuffix(path, ".zip") {
+			log.Fatalf("unexpected file during walk: %s", path)
+		}
+		name := filepath.ToSlash(path)
+		w, err := zw.CreateRaw(&zip.FileHeader{
+			Name:               name,
+			Method:             zip.Store,
+			CompressedSize64:   uint64(len(data)),
+			UncompressedSize64: uint64(len(data)),
+			CRC32:              crc32.ChecksumIEEE(data),
+		})
+		if err != nil {
+			log.Fatal(err)
+		}
+		if _, err := w.Write(data); err != nil {
+			log.Fatal(err)
+		}
+		seen[name] = true
+		return nil
+	})
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err := zw.Close(); err != nil {
+		log.Fatal(err)
+	}
+	if len(seen) == 0 {
+		log.Fatalf("did not find any files to add")
+	}
+	if !seen["US/Eastern"] {
+		log.Fatalf("did not find US/Eastern to add")
+	}
+	if err := os.WriteFile(args[0], zb.Bytes(), 0666); err != nil {
+		log.Fatal(err)
+	}
+}
diff --git a/lib/time/update.bash b/lib/time/update.bash
index d49127b275..48606b9de4 100755
--- a/lib/time/update.bash
+++ b/lib/time/update.bash
@@ -5,35 +5,83 @@
 
 # This script rebuilds the time zone files using files
 # downloaded from the ICANN/IANA distribution.
-# Consult https://www.iana.org/time-zones for the latest versions.
+#
+# To prepare an update for a new Go release,
+# consult https://www.iana.org/time-zones for the latest versions,
+# update CODE and DATA below, and then run
+#
+#	./update.bash -commit
+#
+# That will prepare the files and create the commit.
+#
+# To review such a commit (as the reviewer), use:
+#
+#	git codereview change NNNNNN   # CL number
+#	cd lib/time
+#	./update.bash
+#
+# If it prints "No updates needed.", then the generated files
+# in the CL match the update.bash in the CL.
 
 # Versions to use.
-CODE=2022f
-DATA=2022f
+CODE=2022g
+DATA=2022g
 
 set -e
+
+cd $(dirname $0)
 rm -rf work
 mkdir work
+go build -o work/mkzip mkzip.go # build now for correct paths in build errors
 cd work
 mkdir zoneinfo
-curl -L -O https://www.iana.org/time-zones/repository/releases/tzcode$CODE.tar.gz
-curl -L -O https://www.iana.org/time-zones/repository/releases/tzdata$DATA.tar.gz
+curl -sS -L -O https://www.iana.org/time-zones/repository/releases/tzcode$CODE.tar.gz
+curl -sS -L -O https://www.iana.org/time-zones/repository/releases/tzdata$DATA.tar.gz
 tar xzf tzcode$CODE.tar.gz
 tar xzf tzdata$DATA.tar.gz
 
-make CFLAGS=-DSTD_INSPIRED AWK=awk TZDIR=zoneinfo posix_only
+if ! make CFLAGS=-DSTD_INSPIRED AWK=awk TZDIR=zoneinfo posix_only >make.out 2>&1; then
+	cat make.out
+	exit 2
+fi
 
 cd zoneinfo
-rm -f ../../zoneinfo.zip
-zip -0 -r ../../zoneinfo.zip *
+../mkzip ../../zoneinfo.zip
 cd ../..
-
 go generate time/tzdata
 
-echo
+files="update.bash zoneinfo.zip ../../src/time/tzdata/zipdata.go"
+modified=true
+if git diff --quiet $files; then
+	modified=false
+fi
+
 if [ "$1" = "-work" ]; then
 	echo Left workspace behind in work/.
+	shift
 else
 	rm -rf work
 fi
-echo New time zone files in zoneinfo.zip.
+
+if ! $modified; then
+	echo No updates needed.
+	exit 0
+fi
+
+echo Updated for $CODE/$DATA: $files
+
+commitmsg="lib/time: update to $CODE/$DATA
+
+Commit generated by update.bash.
+
+For #22487.
+"
+
+if [ "$1" = "-commit" ]; then
+	echo "Creating commit. Run 'git reset HEAD^' to undo commit."
+	echo
+	git commit -m "$commitmsg" $files
+	echo
+	git log -n1 --stat
+	echo
+fi
diff --git a/lib/time/zoneinfo.zip b/lib/time/zoneinfo.zip
index d44f355c28..9b31ec1994 100644
--- a/lib/time/zoneinfo.zip
+++ b/lib/time/zoneinfo.zip