Option '--height' destroys results on stdout

[doak]

• I have read through the manual page (man fzf)
• I have the latest version of fzf
• I have searched through the existing issues

Info

• OS
  • Linux
  • Mac OS X
  • Windows
  • Etc.
• Shell
  • bash
  • zsh
  • fish

Problem / Steps to reproduce

If running e.g. fzf --height=30% --bind=alt-enter:"execute(echo TEST)" and hitting alt-enter, the text TEST is not printed although the command seems to be executed (can be tested with e.g. touch).
It works without the option --height. It also works if stdout is piped to a file directly (fzf [...] >/tmp/testfile), but it does not work if piped through cat (fzf [...] | cat).

[doak]

Perhaps related to #1247.

[Nelyah]

Hi, I spend some time today debugging this and came to the same observation as this issue.
@doak did you manage to find a workaround this (besides redirecting fzf's output?)

I think that the reason it works when redirecting to a file vs. to stdout is because in the latter case the output actually gets printed but it immediately gets overwritten by fzf trying to maintain the --height argument.

[fernandomora]

Same problem here:

❯ echo -n "Select an option: " && seq 10 | fzf --height 30%
4

❯ echo -n "Select an option: " && seq 10 | fzf
Select an option: 4

It seems --height is performing some carriage return internally than clears current line

[vovcacik]

Does not seems to be an issue on Windows. When switching to light renderer (i.e. height <=99), there is some garbage (maybe some escape code) printed before the text, but that's it.

(recording is 8 fps)