encoding/json: Invalid json is parsed ok

[cassiobotaro]

Please answer these questions before submitting your issue. Thanks!

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

1.8.3

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

GOARCH="amd64" GOBIN="" GOEXE="" GOHOSTARCH="amd64" GOHOSTOS="linux" GOOS="linux" GOPATH="/home/cassiobotaro/go" GORACE="" GOROOT="/usr/lib/go" GOTOOLDIR="/usr/lib/go/pkg/tool/linux_amd64" GCCGO="gccgo" CC="gcc" GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build528676691=/tmp/go-build -gno-record-gcc-switches" CXX="g++" CGO_ENABLED="1" PKG_CONFIG="pkg-config" CGO_CFLAGS="-g -O2" CGO_CPPFLAGS="" CGO_CXXFLAGS="-g -O2" CGO_FFLAGS="-g -O2" CGO_LDFLAGS="-g -O2"

What did you do?

https://play.golang.org/p/r7FBkS2Cq7

What did you expect to see?

An error because json is not valid.

What did you see instead?

No errors.

[dcheney-atlassian]

IMO this is working as intended. Your example contains two fragments of json {} which is valid, and } which is not. The json package correctly detects the malformed second json fragment.

https://play.golang.org/p/PMADDC99Zy

[bradfitz]

What @dcheney-atlassian said. The docs do say:

A Decoder reads and decodes JSON values from an input stream.
...
Decode reads the next JSON-encoded value from its input and stores it in the value pointed to by v.

If you only want to read one element, use Unmarshal or use https://golang.org/pkg/encoding/json/#Decoder.Token to see if EOF is next.