[Bug]: Error when generating with 'Highres. fix' and 'Upscale latent space image when doing hires. fix'

Is there an existing issue for this?

I have searched the existing issues and checked the recent builds/commits

What happened?

Attempting to use 'Highres. fix' with 'Upscale latent space image when doing hires. fix' results in the error message "UnboundLocalError: local variable 'decoded_samples' referenced before assignment" when it attempts to do the second batch of steps in the console.

When trying to generate "a cat" using stable diffusion 1.5, console prints:

Error completing request4:21,  7.00it/s]
Arguments: ('a cat', '', 'None', 'None', 28, 0, False, False, 1, 1, 7, -1.0, -1.0, 0, 0, 0, False, 1024, 1024, True, 0.7, 0, 0, 0, False, False, None, '', 1, '', 0, '', True, False, False) {}
Traceback (most recent call last):
  File "...\modules\ui.py", line 221, in f
    res = list(func(*args, **kwargs))
  File "...\webui.py", line 63, in f
    res = func(*args, **kwargs)
  File "...\modules\txt2img.py", line 48, in txt2img
    processed = process_images(p)
  File "...\modules\processing.py", line 426, in process_images
    res = process_images_inner(p)
  File "...\modules\processing.py", line 519, in process_images_inner
    samples_ddim = p.sample(conditioning=c, unconditional_conditioning=uc, seeds=seeds, subseeds=subseeds, subseed_strength=p.subseed_strength)
  File "...\modules\processing.py", line 688, in sample
    decoded_samples,
UnboundLocalError: local variable 'decoded_samples' referenced before assignment

Steps to reproduce the problem

Enable 'Upscale latent space image when doing hires. fix' in Settings
Enable 'Highres. fix'
Generate

What should have happened?

The image should have generated

Commit where the problem happens

d885a4a

What platforms do you use to access UI ?

Windows

What browsers do you use to access the UI ?

Google Chrome

I just encountered this bug as well. The problem is specifically when using the highres fix with the "Upscale latent space image when doing hires. fix" option ticked on the settings page. It seems that when that is checked, in the conditional beginning at

stable-diffusion-webui/modules/processing.py

Line 654 in 78b879b

if opts.use_scale_latent_for_hires_fix:

the later-referenced variable decoded_samples is indeed never set in the true branch.

+1 seeing this as well, looks like the bug was introduced in this commit 26a3fd2

Specifically caused by enabling Scale Latent

Yeah just tried it without scaling latent space and it worked, I'll update the issue to include that

+1, I also just ran into this problem.

Same issue here. Log:

Traceback (most recent call last):
  File "C:\Users\user\Desktop\automatic1111\modules\ui.py", line 185, in f
    res = list(func(*args, **kwargs))
  File "C:\Users\user\Desktop\automatic1111\webui.py", line 63, in f
    res = func(*args, **kwargs)
  File "C:\Users\user\Desktop\automatic1111\modules\txt2img.py", line 48, in txt2img
    processed = process_images(p)
  File "C:\Users\user\Desktop\automatic1111\modules\processing.py", line 426, in process_images
    res = process_images_inner(p)
  File "C:\Users\user\Desktop\automatic1111\modules\processing.py", line 519, in process_images_inner
    samples_ddim = p.sample(conditioning=c, unconditional_conditioning=uc, seeds=seeds, subseeds=subseeds, subseed_strength=p.subseed_strength)
  File "C:\Users\user\Desktop\automatic1111\modules\processing.py", line 688, in sample
    decoded_samples,
UnboundLocalError: local variable 'decoded_samples' referenced before assignment

Also have this issue, same error above.

I also have this issue.

Yeah just tried it without scaling latent space and it worked, I'll update the issue to include that

Scale latent has been essential for higher quality generations. Is there a way to fix this without removing it?

Temporary fix is to just revert to commit a0a7024

Sorry everyone, this was as a result of my recent change.

Thank you @rocketgarden for finding the OOS variable.

Adding a pull request in to fix this.

    Temporary fix is to just revert to commit a0a7024c679056dd66beb1832e52041b10143130

Originally posted by @rocketgarden in #3888 (comment)
Non help it

Any ETA on when this will be solved?

The bug is now fixed for me in 9e22a35, wanted to double check it with everyone else to see if I should close this issue.