Pager should not be used for empty output #6400

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1. mgabeler-lee-6rs

   added

   bugSomething isn't workingSomething isn't working

   on Oct 7, 2022
2. cliAutomation

   added

   needs-triageneeds to be reviewedneeds to be reviewed

   on Oct 7, 2022
3. LangLangBart commented on Oct 7, 2022

   

   LangLangBart

   on Oct 7, 2022

   More actions

   could perhaps be solved on the user side with an additional flag in the less command, e.g. -F/--quit-if-one-screen.

   

   ❯ less --version | head -1
   less 608 (PCRE2 regular expressions)
   
   
   ❯ man less | grep -A 3 'quit-if-one-screen'
          -F or --quit-if-one-screen
                 Causes less to automatically exit if the entire file can be dis-
                 played on the first screen.
4. mgabeler-lee-6rs commented on Oct 7, 2022

   

   mgabeler-lee-6rs

   on Oct 7, 2022

   ContributorAuthor

   More actions

   Aah, yeah, and gh tries to set that for common cases via the LESS environment variable:
   

   cli/pkg/iostreams/iostreams.go

   Lines 198 to 200 in 0ecd424

   	if _, ok := os.LookupEnv("LESS"); !ok {
   	pagerEnv = append(pagerEnv, "LESS=FRX")
   	}

   
   but I have a more .. complex $LESS already set without -F (so that if I explicitly do foo | less, I'm sure to get less invoked)

   The gh config or GH_PAGER="less -F" works as a workaround 👍

   👍React with 👍1Reacted by LangLangBart
5. LangLangBart commented on Oct 9, 2022

   

   LangLangBart

   on Oct 9, 2022

   More actions

   Just for clarification for any maintainer.

   I also set the environment variable LESS without the flag -F, therefore I get Byte 0/0 (END) as seen in the GIF.

   # .zshrc
   # <--------- Less---------- >
   # from https://github.com/nablaa/dotfiles/blob/master/.zsh/environment.zsh
   # R - Raw color codes in output (don't remove color codes)
   # K - quit less immediately with ^C
   # q - be more quiet
   # M - Long prompts ("Line X of Y")
   # ~ - Don't show those weird ~ symbols on lines after EOF
   # g - Highlight results when searching with slash key (/)
   # I - Case insensitive search
   # s - Squeeze empty lines to one
   # w - Highlight first line after PgDn
   export LESS="-RKqM~gIsw"
   
   # Less Colors for Man Pages
   export LESS_TERMCAP_mb=$'\E[01;31m'      # begin blinking
   export LESS_TERMCAP_md=$'\E[01;38;5;74m' # begin bold
   export LESS_TERMCAP_me=$'\E[0m'          # end mode
   export LESS_TERMCAP_se=$'\E[0m'          # end standout-mode
   export LESS_TERMCAP_so=$'\E[01;31m'      # begin standout-mode - info box
   export LESS_TERMCAP_ue=$'\E[0m'          # end underline
   export LESS_TERMCAP_us=$'\E[01;32m'      # begin underline
   # disable the creation of the ~/.lesshst file
   export LESSHISTFILE=-

   I guess the issue can be closed ?
6. mislav commented on Oct 10, 2022

   

   mislav

   on Oct 10, 2022

   Contributor

   More actions

   Thanks for the discussion so far!

   Every tool I use that understands this variable, except gh, understands that output smaller than a single terminal window doesn't need to go through the pager.

   Here is git CLI piping output definitely smaller than my terminal window through the configured pager:

   

   It is not the responsibility of the tool itself to determine your viewport size and how to handle pagination. Instead, that is the responsibility of the pager utility itself. Thus, gh will always start a pager for any amount of output. But, you are right that starting a pager for no output whatsoever is not really great user experience. Let's fix that!

   In the meantime please use the already discovered workaround by setting the LESS=FRX environment variable or GH_PAGER=less -FRX.
7. mislav

   added

   priority-3Affects a small number of users or is largely cosmeticAffects a small number of users or is largely cosmetic

   help wantedContributions welcomeContributions welcome

   and removed

   needs-triageneeds to be reviewedneeds to be reviewed

   on Oct 10, 2022
8. mislav

   changed the title [-]Pager should be used only when output doesn't fit on screen[/-] [+]Pager should not be used for empty output[/+] on Oct 10, 2022
9. mislav

   closed this as completedin #6419on Oct 13, 2022