image/jpeg: mishandles progressive JPEG

[gopherbot]

by dan.pupius:

To reproduce:
- decode the attached image

What is the expected output?

A decoded image.  Works in every other image viewer I tried.  (Preview, Chrome,
GraphicsMagick)

What do you see instead?

invalid JPEG format: missing 0xff00 sequence
see: http://golang.org/src/pkg/image/jpeg/huffman.go

Which version are you using?  (run 'go version')

go version devel +37afbf6361e2 Tue Nov 12 10:03:13 2013 -0800 darwin/amd64
Which version are you using?  (run 'go version')


I realize this is an expected error, but given that other viewers manage to decode the
image correctly I wonder if this is truly an error case or can be gracefully handled. 
(Pardon my ignorance of the jpeg spec)

Attachments:

1. 0*CZbFf74phRAk3ngZ.jpeg (615890 bytes)

[adg]

Comment 1:

Labels changed: added priority-someday, removed priority-triage.

Owner changed to @nigeltao.

[rsc]

Comment 2:

Labels changed: added go1.3maybe.

[rsc]

Comment 3:

Labels changed: added release-none, removed go1.3maybe.

[rsc]

Comment 4:

Labels changed: added repo-main.

[robpike]

Comment 5:

The file is a progressive JPEG, a feature only recently supported. The error occurs in
the first scan decoding the huffman block. I suspect the problem is just a bug in the
new code. If Nigel doesn't get to it first, I'll dig into it when I have my JPEG
standard book handy.
Other tests I've run show this to be a syntactically correct JPEG. Here's the dump of
the piece through the first scan section.
SOI
APP0 len=16
DQT:    p = 0, table = 0
DQT:    p = 0, table = 1
SOF2:   Progressive DCT - Huffman coding
    990 wide, 1345 high, 8 deep, 3 components
    component 1: 2 hsample, 2 vsample, quantization table 0
    component 2: 1 hsample, 1 vsample, quantization table 1
    component 3: 1 hsample, 1 vsample, quantization table 1
DHT:    class = 0, table = 0
SOS:    1 components
    component 1: 0 DC, 0 AC
    start spectral 0
    end spectral 0
    ah = 0, al = 0
sequence length 22370 with 35 stuffs
Should be fixed for Go 1.3 if possible. I suspect this isn't the only file that causes
the problem.

Labels changed: added release-go1.3, removed priority-someday, release-none.

Status changed to Accepted.

[nigeltao]

Comment 7:

This issue was closed by revision ea34ca7.

Status changed to Fixed.