net/http: json decoding fails from httptest in tip, works in 1.4 and over bytes.Buffer

[ThomasHabets]

Code

http://play.golang.org/p/DPZUao3rPB

Should output (and does under Go 1.4)

Decoding with bytes.Buffer: <nil>, {"bar"}
Decoding with http stream: <nil>, {"bar"}
Decoding with http stream bouncing on bytes.Buffer: <nil>, {"bar"}
Yes, "{ \"foo\": \"bar\" }" really is "{ \"foo\": \"bar\" }"

With tip(129cfa2) outputs

$ go run lalatest.go
Decoding with bytes.Buffer: <nil>, {"bar"}
Decoding with http stream: EOF, {""}
Decoding with http stream bouncing on bytes.Buffer: <nil>, {"bar"}
Yes, "{ \"foo\": \"bar\" }" really is "{ \"foo\": \"bar\" }"

Expected

not EOF. Doesn't matter which io.Reader it's read from, it should either be seen as valid or it shouldn't.

[ianlancetaylor]

CC @bradfitz

[bradfitz]

This is a recent regression.

Trying to find where. Rev a60c536 is bad.

[bradfitz]

Rev 9c55792 is good, and rev 0cf48b4 is bad. So the break came at:
0cf48b4: encoding/json: add JSON streaming parse API

/cc @rsc

[rsc]

Fixed by CL 12726 and by CL 12740. (The release is getting closer so we double-fix things now.)