0.5.0 giving "Premature end of JPEG file" error.

got this error when the file is not really a jpeg, basically the extension is wrong. Did you check that ?

Thanks for the reply, . I hadn't checked that! This post is after I've walked through everything again and not necessarily in chronological order of my actions ;p

Exploring the issue

I removed many images until the error stopped occurring and started adding in one by one. As I was adding in the images, and getting errors on particular ones, I realized the the one it errors on may not be the last one or even next one in the list of those it has optimized. So I used the --force option to see if I could get a little more data, and wound up with this:

Running "imagemin:dist" (imagemin) task
✔ _dist/images/code_bg.png (already optimized)
✔ _dist/images/bird_32_gray_fail.png (already optimized)
✔ _dist/images/bird_32_gray.png (already optimized)
✔ _dist/images/comics/comic.jpg (already optimized)
✔ _dist/images/comics/characters.jpg (already optimized)
✔ _dist/images/comics/introduction-to-keep-calm-and-code-on.jpg (already optimized)
✔ _dist/images/comics/kcco-ep1.jpg (already optimized)
✔ _dist/images/comics/keep-calm-and-code-on-1-pokemon-institute-security-reports.jpg (already optimized)
Warning: Premature end of JPEG file
 Used --force, continuing.

/Users/joshmatz/Projects/blog/node_modules/grunt-contrib-compass/node_modules/tmp/lib/tmp.js:261
  throw err;
        ^
TypeError: Cannot read property 'diffSizeRaw' of undefined
    at /Users/joshmatz/Projects/blog/node_modules/grunt-contrib-imagemin/tasks/imagemin.js:35:35
    at Socket.<anonymous> (/Users/joshmatz/Projects/blog/node_modules/grunt-contrib-imagemin/node_modules/image-min/imagemin.js:70:16)
    at Socket.EventEmitter.emit (events.js:95:17)
    at Socket.<anonymous> (_stream_readable.js:736:14)
    at Socket.EventEmitter.emit (events.js:92:17)
    at emitReadable_ (_stream_readable.js:408:10)
    at emitReadable (_stream_readable.js:404:5)
    at readableAddChunk (_stream_readable.js:165:9)
    at Socket.Readable.push (_stream_readable.js:127:10)
    at Pipe.onread (net.js:526:21)
</anonymous></anonymous>

The only file I currently have triggering is *-7-*. As you can see, though it appears to be stopping at after *-1-*, when I remove 7 the error goes away completely. Now that it's narrowed down to this particular image, I have found that it is, in fact, a corrupt image. Photoshop won't open it and gives this warning:

Could not complete your request because a JPEG marker segment length is too short (the file may be truncated or incomplete).

I'll see if I can get my hands on a non-corrupt image and I'm sure that will fix it.

Fixing the issue without fixing the issue

Oddly enough, with the additional --force data, I found #143 which seems to be the same problem. mentioned that changing her src string fixed it. I tried that, and what do you know? Error is gone! That's not necessarily the best solution as now every time I want a new image folder I have to manually add to our Gruntfile... I'm also not sure why changing my src string has any effect on whether the corrupt image is able to be optimized...

Going forward

While my initial instincts on a corrupt jpeg were correct (seeing as how that is what the error basically says!), narrowing down just which corrupt file it was was not that easy since the listed optimized files don't seem to match to the file that actually causes the error. I wonder if there's a way to output this information better?

Also curious why the above solution worked and if it's working correctly. If it's working, I wonder if it's possible to output a warning rather than completely breaking?

hi,

Regarding the error itself, TypeError: Cannot read property 'diffSizeRaw' of undefined yes it is easy to fix in fact. there shouldbe a else starting on line 33 until line 43.

For better debuging, see line 32, the error message is damn poor and rely on the external binaries to eventually provide interesting information.

Lastly, concerning #143, i can t say, i have same interrogations !

Remains the missing pr !

Try installing 0.6.0-pre by running npm install gruntjs/grunt-contrib-imagemin and see if the problem persists.

Actually works with PNG, I was trying with 0.5.0 and always save 0-bytes files.

I just update to 0.6.0-pre and now everything is fine (for PNGs).

:+1:

0.6.0 is out. Let us know if you still have this problem.