I see some issues on some of my custom scripts.

Only the first line is shown even after the preview has fully loaded.

When I start to scroll to the bottom, then I see the second line and the ones after that.

I'm trying to create a simple example.

Actually it can be reproduced simply with the following :

FZF_DEFAULT_OPTS="" ./bin/fzf --preview 'echo "1"; sleep 1; echo 2'

See recording :

You can also reproduce the same issue (probably), with the following :

FZF_DEFAULT_OPTS="" ./bin/fzf --preview 'for i in $(seq 10); do echo $i; sleep 0.13; done' 

Here, on my computer, only the first 3 numbers are shown (numbers 1 to 3).

with :

FZF_DEFAULT_OPTS="" ./bin/fzf --preview 'for i in $(seq 10); do echo $i; sleep 0.11; done'

it writes number from 1 to 8.

with FZF_DEFAULT_OPTS="" ./bin/fzf --preview 'for i in $(seq 10); do echo $i; sleep 0.10; done',

everything works fine, so there is something special happening near 1 tenth of a second.

Nice find, 63444b4 should fix that.

I'm also seeing an issue where fzf not terminating the running command when the cursor is moved. Need further investigation.

There's one behavior I'm not sure is intended :

When I run the following :

fzf ./bin/fzf --preview ' yes | head -n 20; sleep 5; echo foo ;  ' --preview-window 'up:nohidden'

It shows the 1/20 while loading, even though the preview does not have a scroll.

After the sleep and the echo foo however, the 1/20 disappears.

I suggest to put only the loading screen in this case, not the 1/20 part.

Maybe to avoid some "jittering", it would make more sense to put the loading on the right of the pagination, or maybe one line below that.

This is the intended behavior as of now. You can see there's a braille character indicating that the stream is open (i.e. ⠋ 1/20). We don't know if the final number of lines will exceed the height of the window or not at this point.

# `⠋ 1/20` disappears when the stream is closed
fzf --preview ' yes | head -n 20; sleep 5; echo foo ;  ' --preview-window 'up:nohidden'

# `1/1020` remains (spinner on the left gone)
fzf --preview ' yes | head -n 20; sleep 5; seq 1000; sleep 1' --preview-window 'up:nohidden'

One idea is to only print ⠋ without numbers before the content overflows.

One idea is to only print ⠋ without numbers before the content overflows.

Yes, exactly, that is what I thought would make more sense, but I also would understand that you'd prefer to keep current behavior.

I have just tested again and it seems to work well for me.

I'm going to merge this as it all seems to be working fine and test it over the next few days. Please let me know if you find any issues.

Yes, sure I will !