mime: incorrect definition of extension by mime type audio/webm

[sintanial]

Please answer these questions before submitting your issue. Thanks!

What version of Go are you using (go version)?

go version go1.9.1 linux/amd64

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/root/go"
GORACE=""
GOROOT="/usr/local/go"
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build626851427=/tmp/go-build -gno-record-gcc-switches"
CXX="g++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"

What did you do?

Call mime.ExtensionsByType("audio/webm") return empty result. It's reproduced only on linux (i tested it only on ubuntu 16.04). This problem occurs because there in no corresponding entry for audio/webm in /etc/mime.types.
I don't know it's golang bug or not, but it's crashed all my service yesterday :). I think mime.ExtensionsByType must return same result on different OS ?

What did you expect to see?

Expect to return slice [.weba]

What did you see instead?

Empty result

[ianlancetaylor]

For functions like ExtensionsByType the mime package has to defer to the operating system. There is no reasonable way for us to provide the information for every MIME type for every operating system, because there is no standard for us to follow. At least, there is no standard that is going to help for a new MIME type like audio/webm. In this case you suggest that it should return ".weba" but looking around on the net shows that some systems use ".webm" instead.

Closing because I don't think there is anything we can do in the Go standard library.

[sintanial]

ok, thx for answer