archive/zip: CreateRaw ignores FileHeader.Modified

[vbmithr]

Go version

go version go1.25.4 X:nodwarf5 linux/amd64

Output of go env in your module/workspace:

AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE=''
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/home/vb/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/home/vb/.config/go/env'
GOEXE=''
GOEXPERIMENT='nodwarf5'
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build1923640358=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/dev/null'
GOMODCACHE='/home/vb/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/vb/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/lib/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/vb/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/lib/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.25.4 X:nodwarf5'
GOWORK='/home/vb/code/dm/go/go.work'
PKG_CONFIG='pkg-config'

What did you do?

Used CreateRaw to add a raw (aka already compressed) entry to a zip file

	zipWriter := zip.NewWriter(w)
	defer func() {
		e = errors.Join(e, zipWriter.Close())
	}()

	// Create ZIP entry header
	header := &zip.FileHeader{
		Name:               entryName,
		Method:             zip.Deflate,
		CRC32:              crc32,
		CompressedSize64:   uint64(deflateSize),
		UncompressedSize64: uint64(uncompressedSize),
	}
	// Deprecated, but we have no other choice to set the zip file
	// modified. Setting the Modified field does not work with
	// CreateRaw! https://github.com/golang/go/issues/76741
	header.SetModTime(stat.ModTime())

	// Create writer for this entry
	entryWriter, err := zipWriter.CreateRaw(header)
	if err != nil {
		return err
	}

I was expecting that putting the Modified field in FileHeader would set the timestamp of the entry.
Unfortunately I must use the deprecated function SetModTife here in order set the timestamp.

What did you see happen?

Setting the Modified field in FileHeader should set the entry timestamp like it happen for entries created by CreateHeader

What did you expect to see?

the Modified field in FileHeader should be honored

[gabyhelp]

Related Issues

• archive/zip: FileHeader.FileInfo().ModTime() should use Modified #28350 (closed)
• archive/zip: record time stamps in "Extended Timestamp Extra Field" #10242 (closed)
• archive/zip does not set proper CRC, size and modification date/time #28602 (closed)
• archive/zip: fails to encode filenames with utf-8 chars if 'Modified' is not set #44187 (closed)
• archive/zip: use Modified in FileHeader.FileInfo #28352 (closed)
• archive/zip: CRC, Compressed Length, and Uncompressed Length fields are not filled in on local headers created by zip.Writer #54666 (closed)
• archive/zip: discrepancy between os.Fileinfo.Modtime and zip.FileHeader.Modified in Go 1.13 #33494 (closed)
• Missing function: zip.FileHeader.SetModTime(time.Time) #2574 (closed)
• archive/zip: takes mtime from wrong part of infoZipUnixExtraID extra headers #23901 (closed)

Related Code Changes

• archive/zip: use Modified in FileHeader.FileInfo

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[dr2chase]

@dsnet, @bradfitz
looking at the gabyhelp comment above suggests some sort of a history here.

[gopherbot]

Change https://go.dev/cl/732600 mentions this issue: archive/zip: honor Modified field in CreateRaw