"gum spin --show-output" truncates output to match terminal size

[wmedlar]

Describe the bug

gum spin --show-output truncates output from the command to match the size of the current terminal.
For example, if your terminal were 14 lines tall by 80 lines wide, gum spin --show-output would print only first 80 characters from the last 14 lines of output from whatever command was run.

To Reproduce
Steps to reproduce the behavior:

1. Determine the size of your current terminal. This one is intentionally small to better demonstrate the issue.

$ tput cols
30
$ tput lines
14

2. Run gum spin with a command that produces larger output than your terminal size. The example command prints the numbers 0 through 100 with fixed-width zero padding of 31 characters. The "ones" place is the 31st character, extending beyond the terminal width, and will be cut off by gum.

$ gum spin --show-output -- printf '%031i\n' {1..100}
000000000000000000000000000007
000000000000000000000000000007
000000000000000000000000000008
000000000000000000000000000008
000000000000000000000000000008
000000000000000000000000000008
000000000000000000000000000008
000000000000000000000000000008
000000000000000000000000000008
000000000000000000000000000008
000000000000000000000000000008
000000000000000000000000000008
000000000000000000000000000009
000000000000000000000000000009
000000000000000000000000000009
000000000000000000000000000009
000000000000000000000000000009
000000000000000000000000000009
000000000000000000000000000009
000000000000000000000000000009
000000000000000000000000000009
000000000000000000000000000009
000000000000000000000000000010

Expected behavior

gum spin --show-output should print the entire, untruncated output of the command once the command returns.

Desktop (please complete the following information):

• OS: MacOS 14.7
• Version: 0.15.1

Additional context
Same behavior in both in bash 5.2 and zsh 5.9.

[caarlos0]

I think then the spinner should go below the output for it to make sense

in any case, I agree it should print the whole output if piped and once finished, not sure if while running, though

[wmedlar]

Sorry, let me edit the issue to clarify the behavior I expect. I'm only expecting the full output once the command completes, not while the command is still running / the spinner is still spinning.

I also noticed that the output is cut off horizontally as well. I'll add reproduction steps for that too.

[wmedlar]

Looks like this might be intended behavior of the bubbletea renderer for both the height truncation and the width truncation.