git/list[1] front-page[2] threads[3] people[4] search[5] about
 

Re: [PATCH 1/2] Allow __git_ps1 to be used in PROMPT_COMMAND

From
Junio C Hamano <gitster@pobox.com>
Date
Oct 8, 2012, 18:12 UTC
Message-ID
<7vr4p8lto5.fsf@alter.siamese.dyndns.org>
In-Reply-To
<20121005210945.GA4961@simaj.xs4all.nl>
Simon Oosthoek <s.oosthoek@xs4all.nl> writes:
Show 5 quoted lines
> changes __git_ps1 to not just allow use in setting PS1
> with __git_ps1 in a command substitution, but also allows
> __git_ps1 to be used as PROMPT_COMMAND in bash.
> This has advantages for using color and I think it is more
> elegant

Is "and I think" necessary? I do not think it matters what _you_ think when judging it is worth including in the future releases ;-)

A lot more important thing to say is why it has advantages for using color (remember, it took a few rounds of back and forth with me). Unless you are going to explain the same to all the people who are reading the "git log" output 6 months down the road, that is a more appropriate thing to write here.

Show 36 quoted lines
>  contrib/completion/git-prompt.sh |   51 +++++++++++++++++++++++++++++++++-----
>  1 file changed, 45 insertions(+), 6 deletions(-)
>
> diff --git a/contrib/completion/git-prompt.sh b/contrib/completion/git-prompt.sh
> index 29b1ec9..c50c94a 100644
> --- a/contrib/completion/git-prompt.sh
> +++ b/contrib/completion/git-prompt.sh
> @@ -10,9 +10,14 @@
>  #    1) Copy this file to somewhere (e.g. ~/.git-prompt.sh).
>  #    2) Add the following line to your .bashrc/.zshrc:
>  #        source ~/.git-prompt.sh
> -#    3) Change your PS1 to also show the current branch:
> -#         Bash: PS1='[\u@\h \W$(__git_ps1 " (%s)")]\$ '
> -#         ZSH:  PS1='[%n@%m %c$(__git_ps1 " (%s)")]\$ '
> +#    3a) In ~/.bashrc set PROMPT_COMMAND=__git_ps1
> +#        To customize the prompt, provide start/end arguments
> +#        PROMPT_COMMAND="__git_ps1 '\u@\h:\w (' ')\$ '"
> +#    3b) Alternatively change your PS1 to call __git_ps1 as
> +#        command-substitution:
> +#        Bash: PS1='[\u@\h \W$(__git_ps1 " (%s)")]\$ '
> +#        ZSH:  PS1='[%n@%m %c$(__git_ps1 " (%s)")]\$ '
> +#        the optional argument will be used as format string
>  #
>  # The argument to __git_ps1 will be displayed only if you are currently
>  # in a git repository.  The %s token will be the name of the current
> @@ -194,11 +199,41 @@ __git_ps1_show_upstream ()
>  
>  
>  # __git_ps1 accepts 0 or 1 arguments (i.e., format string)
> +# when called from PS1 using command substitution
> +# in this mode it returns text to add to bash PS1 prompt (includes branch name) or
> +# __git_ps1 accepts 0 or 2 arguments when called from PROMPT_COMMAND
> +# in that case it _sets_ PS1. The arguments are parts of a PS1 string.
> +# when both arguments are given, the first is prepended and the second appended
> +# to the state string when assigned to PS1, otherwise default start/end strings
> +# are used.

Sorry, but I cannot parse this. Is this meant to be a two-item list, one describing the command substitution mode (zero or 1 arguments) and the other describing the prompt command mode? If so, perhaps replacing the " or" at the end of the first item with ".\n#\n" would make it readable.

Show 15 quoted lines
>  __git_ps1 ()
>  {
> +	local pcmode=yes
> +	local ps1pc_start='\u@\h:\w '
> +	local ps1pc_end='\$ '
> +
> +	case "$PROMPT_COMMAND" in
> +		__git_ps1*)
> +			if [ $# = 2 ]; then
> +				ps1pc_start="$1"
> +				ps1pc_end="$2"
> +			fi
> +			case "$PS1" in
> +			*__git_ps1*)
> +				echo '__git_ps1: overwriting PS1 due to PROMPT_COMMAND'

Is this supposed to be an error and/or warning message? Why is it worth warning only when you are overwriting __git_ps1 style of PS1 and not other user customization?

Show 5 quoted lines
> +			;;
> +			esac
> +		;;
> +		*)  pcmode=no ;; #no output
> +	esac

Please align outer "case" "its arms)" and "esac" at the same column, like you did for the inner "case/esac".

Auto-detetction based on PROMPT_COMMAND is a flaky approach. In practice, nobody will call PROMPT_COMMAND with the __git_ps1 without any parameter (100% people want their prompt to end with some sort of whitespace so they want the "what comes after what is computed", aka $2), and even more importantly, nobody has been relying on use of 0 argument form of __git_ps1 in PROMPT_COMMAND. So why not always require 2 args and take that as a cue to go into the pc mode?

Show 22 quoted lines
> +
>  	local g="$(__gitdir)"
> -	if [ -n "$g" ]; then
> +	if [ -z "$g" ]; then
> +		if [ $pcmode = yes ]; then
> +			#In PC mode PS1 always needs to be set
> +			PS1="$ps1pc_start$ps1pc_end"
> +		fi
> +	else
>  		local r=""
>  		local b=""
>  		if [ -f "$g/rebase-merge/interactive" ]; then
> @@ -284,6 +319,10 @@ __git_ps1 ()
>  		fi
>  
>  		local f="$w$i$s$u"
> -		printf -- "${1:- (%s)}" "$c${b##refs/heads/}${f:+ $f}$r$p"
> +		if [ $pcmode = yes ]; then
> +			PS1="$ps1pc_start($c${b##refs/heads/}${f:+ $f}$r$p)$ps1pc_end"
> +		elif [ $pcmode = no ]; then
> +			printf -- "${1:- (%s)}" "$c${b##refs/heads/}${f:+ $f}$r$p"
> +		fi

Are there $pcmode other than yes or no? Why not just "else", instead of performing the test twice?

>  	fi
>  }
Previous: Simon OosthoekNext: Simon Oosthoek
Message 26 of 49 in “bash completion with colour hints”
  1. Simon OosthoekSep 26, 2012
  2. Ramkumar RamachandraSep 26, 2012
  3. Simon OosthoekSep 26, 2012
  4. Junio C HamanoSep 27, 2012
  5. Michael J GruberSep 27, 2012
  6. Michael J GruberSep 27, 2012
  7. Simon OosthoekSep 27, 2012
  8. Andreas SchwabSep 27, 2012
  9. Simon OosthoekSep 27, 2012
  10. Add __git_ps1_pc to use as PROMPT_COMMANDSimon Oosthoek, Sep 28, 2012
  11. Junio C HamanoSep 28, 2012
  12. Simon OosthoekOct 1, 2012
  13. Junio C HamanoOct 1, 2012
  14. Simon OosthoekOct 1, 2012
  15. Junio C HamanoOct 1, 2012
  16. Simon OosthoekOct 1, 2012
  17. Junio C HamanoOct 1, 2012
  18. Simon OosthoekOct 1, 2012
  19. Junio C HamanoOct 1, 2012
  20. Michael J GruberOct 2, 2012
  21. Simon OosthoekOct 2, 2012
  22. Junio C HamanoOct 2, 2012
  23. Simon OosthoekOct 2, 2012
  24. Junio C HamanoOct 2, 2012
  25. 1/2 Allow __git_ps1 to be used in PROMPT_COMMANDSimon Oosthoek, Oct 5, 2012
  26. Junio C HamanoOct 8, 2012
  27. Simon OosthoekOct 8, 2012
  28. Junio C HamanoOct 8, 2012
  29. 1/2 Allow __git_ps1 to be used in PROMPT_COMMANDSimon Oosthoek, Oct 10, 2012
  30. Junio C HamanoOct 10, 2012
  31. 2/2 show color hints based on state of the git treeSimon Oosthoek, Oct 10, 2012
  32. 1/2 Allow __git_ps1 to be used in PROMPT_COMMANDSimon Oosthoek, Oct 10, 2012
  33. 2/2 show color hints based on state of the git treeSimon Oosthoek, Oct 10, 2012
  34. 2/2 show color hints based on state of the git treeSimon Oosthoek, Oct 5, 2012
  35. Michael J GruberOct 15, 2012
  36. Simon OosthoekOct 15, 2012
  37. Michael J GruberOct 15, 2012
  38. Simon OosthoekOct 15, 2012
  39. Simon OosthoekOct 15, 2012
  40. Michael J GruberOct 15, 2012
  41. Simon OosthoekOct 8, 2012
  42. Simon OosthoekOct 15, 2012
  43. Junio C HamanoOct 15, 2012
  44. 3/3 Change colors to be based on git status -sb in color modeSimon Oosthoek, Oct 16, 2012
  45. Junio C HamanoOct 16, 2012
  46. 3/3 Change colors to be based on git status -sb in color modeSimon Oosthoek, Oct 16, 2012
  47. Junio C HamanoOct 16, 2012
  48. Junio C HamanoOct 16, 2012
  49. Simon OosthoekOct 17, 2012

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.