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[PATCH] bash completion: Support "divergence from upstream" messages in __git_ps1

From
ASAndrew Sayers <andrew-git@pileofstuff.org>
Date
Jun 12, 2010, 20:50 UTC
Message-ID
<4C13F32B.7060106@pileofstuff.org>
In-Reply-To
<cover.1276336602.git.trast@student.ethz.ch>

Add a notification in the command prompt specifying whether (and optionally how far) your branch has diverged from its upstream. This is especially helpful in small teams that very frequently (forget to) push to each other.

Support git-svn upstream detection as a special case, as migrators from centralised version control systems are especially likely to forget to push.

Also provide ways for the user to specify a custom upstream, or code that figures out the upstream.

Support for other types of upstream than SVN should be easy to add if anyone is so inclined. ---

This is based largely on Thomas' patch, but with some significant differences. Thanks once again Thomas.

I've made the quieter </> behaviour the default. A major use case for me will be over-the-shoulder checking for the rest of my team - I can probably add a couple of characters to their prompts without raising any eyebrows, but " u+1-2" is enough UI to provoke people's curiosity. If they're not interested in this feature, it will be harder for me to justify 6+ interesting characters than 2 boring ones. I haven't gone with Steven's ↑/↓ idea because I don't want to field complaints about "my terminal is Unicode-aware but those characters are unreadable in my default font". I'd rather people edit the source for that sort of thing.

I've added a message in the "equal to upstream" case, to differentiate it from the "no upstream" case. Again, this is an over-the-shoulder issue - when I see an "=" (or " u=") in someone's prompt, I don't have to patronise them about whether they've e.g. misconfigured their branch.

I've added a legacy mode to make the script work without "git rev-list --count". I really like the "git rev-list --count" option, but getting my team to run a patched version of git would be quite a bit more trouble than it's worth. If people strongly object to this feature then I can hide it better or remove it from the public patch.

The documentation for the "legacy" option currently reads "don't use the '--count' option available in recent versions of git-rev-list". If/when "--count" makes it into master, this could be changed to "compatibility mode for git versions less than <version when --count went in>".

I've made several efficiency improvements, only one of which is particularly interesting: instead of doing an `echo`, the code now sets `p=` directly. Admittedly this is messier, but $p is dynamically scoped and testing suggests that setting it knocks 10% or so off run-time.

The code should now handle multiple SVN repositories, by getting all svn-remote.*.url config options with a --get-regexp.

I like the "ref" option, but I'm not really sure when "eval" would be useful. I've changed it here to "cmd" so people are encouraged to put their work in a script.

I've tried to take Szeder's comments on board, but I'm not really sure what the problem with unnecessary empty lines is. If this is a convention I'm not aware of, could you explain in a bit more detail?

	- Andrew
 contrib/completion/git-completion.bash |  144 +++++++++++++++++++++++++++++++-
 1 files changed, 143 insertions(+), 1 deletions(-)
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 57245a8..7e40f65 100755
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -42,6 +42,23 @@
 #       set GIT_PS1_SHOWUNTRACKEDFILES to a nonempty value. If there're
 #       untracked files, then a '%' will be shown next to the branch name.
 #
+#       If you would like to see the difference between HEAD and its
+#       upstream, set GIT_PS1_SHOWUPSTREAM to a nonempty value.  A "<"
+#       indicates you are behind, ">" indicates you are ahead, and
+#       "<>" indicates you have diverged.  You can further control the
+#       output by setting GIT_PS1_SHOWUPSTREAM to a space-separated
+#       list of values:
+#           git           compare HEAD to @{upstream}
+#           svn           compare HEAD to your SVN upstream
+#           ref=<ref>     compare HEAD to <ref>
+#           cmd=<command> compare HEAD to the output of <command>
+#           verbose       show number of commits ahead/behind (+/-) upstream
+#           legacy        don't use the '--count' option available in recent
+#                         versions of git-rev-list
+#       If none of 'git', 'svn', 'ref' or 'cmd' are specified, your SVN
+#       upstream will be used if configured, or your git upstream otherwise.
+#
+#
 # To submit patches:
 #
 #    *) Read Documentation/SubmittingPatches
@@ -78,6 +95,126 @@ __gitdir ()
 	fi
 }
 
+# stores the divergence from upstream in $p
+# used by GIT_PS1_SHOWUPSTREAM
+__git_ps1_show_upstream ()
+{
+	local cfg=( $( git config --get-regexp '^bash\.showUpstream$|^svn-remote\..*\.url$' 2>/dev/null ) )
+	local svn_remote=() svn_url_pattern count n
+	local upstream=git legacy verbose
+
+	# get some config options from git-config
+	for (( n=0; "$n" != "${#cfg[@]}"; ++n )); do
+		case "${cfg[$n]}" in
+			bash.showUpstream)
+				GIT_PS1_SHOWUPSTREAM="${cfg[$((n+1))]}"
+				if [[ -z "${GIT_PS1_SHOWUPSTREAM}" ]]; then
+					p=""
+					return
+				fi
+				;;
+			svn-remote.*.url)
+				svn_remote[ $(( ${#svn_remote[@]} + 1 )) ]="${cfg[$((n+1))]}"
+				svn_url_pattern+="\\|${cfg[$((n+1))]}"
+				upstream=svn # default upstream is SVN if available
+				;;
+		esac
+	done
+
+	# parse configuration values
+	for option in ${GIT_PS1_SHOWUPSTREAM}; do
+		case "$option" in
+			git|svn|"ref="*|"cmd="*) upstream="$option" ;;
+			verbose) verbose=1 ;;
+			legacy)  legacy=1  ;;
+		esac
+	done
+
+	# Find our upstream
+	case "$upstream" in
+		git)    upstream="@{upstream}" ;;
+		ref\=*) upstream="${option:4}" ;;
+		cmd\=*) upstream=$( "${option:4}" ) ;;
+		svn)
+			# get the upstream from the "git-svn-id: ..." in a commit message
+			# (git-svn uses essentially the same procedure internally)
+			upstream=( $(git log --first-parent -1 \
+					--grep="^git-svn-id: \(${svn_url_pattern:2}\)") )
+			if [[ -n "$upstream" ]]; then
+				upstream=${upstream[ ${#upstream[@]} - 2 ]}
+				upstream=${upstream%@*}
+				for (( n=1; "$n" <= "${#svn_remote[@]}"; ++n )); do
+					upstream=${upstream#${svn_remote[$n]}}
+				done
+
+				if [[ -z "$upstream" ]]; then
+					# default branch name for checkouts with no layout:
+					upstream=${GIT_SVN_ID:-git-svn}
+				else
+					upstream=${upstream#/}
+				fi
+
+			fi
+			;;
+	esac
+
+	# Find how many commits we are ahead/behind our upstream
+	if [[ -z "$legacy" ]]; then
+		count="$(git rev-list --count --left-right \
+				"$upstream"...HEAD 2>/dev/null)"
+	else
+		# produce equivalent output to --count for older versions of git
+		local commits
+		if commits="$( git rev-list --left-right "$upstream"...HEAD 2>/dev/null )"
+		then
+			local commit behind=0 ahead=0
+			for commit in $commits
+			do
+				case "$commit" in
+					"<"*) let ++behind
+						;;
+					*)    let ++ahead
+						;;
+				esac
+			done
+			count="$behind	$ahead"
+		else
+			count=""
+		fi
+	fi
+
+	# calculate the result
+	if [[ -z "$verbose" ]]; then
+		case "$count" in
+			"") # no upstream
+				p="" ;;
+			"0	0") # equal to upstream
+				p="=" ;;
+			"0	"*) # ahead of upstream
+				p=">" ;;
+			*"	0") # behind upstream
+				p="<" ;;
+			*)	    # diverged from upstream
+				p="<>" ;;
+		esac
+	else
+		case "$count" in
+			"") # no upstream
+				p="" ;;
+			"0	0") # equal to upstream
+				p=" u=" ;;
+			"0	"*) # ahead of upstream
+				p=" u+${count#0	}" ;;
+			*"	0") # behind upstream
+				p=" u-${count%	0}" ;;
+			*)	    # diverged from upstream
+				p=" u+${count#*	}-${count%	*}" ;;
+		esac
+	fi
+
+}
+
+
 # __git_ps1 accepts 0 or 1 arguments (i.e., format string)
 # returns text to add to bash PS1 prompt (includes branch name)
 __git_ps1 ()
@@ -132,6 +269,7 @@ __git_ps1 ()
 		local s
 		local u
 		local c
+		local p
 
 		if [ "true" = "$(git rev-parse --is-inside-git-dir 2>/dev/null)" ]; then
 			if [ "true" = "$(git rev-parse --is-bare-repository 2>/dev/null)" ]; then
@@ -159,10 +297,14 @@ __git_ps1 ()
 			      u="%"
 			   fi
 			fi
+
+			if [ -n "${GIT_PS1_SHOWUPSTREAM-}" ]; then
+				__git_ps1_show_upstream
+			fi
 		fi
 
 		local f="$w$i$s$u"
-		printf "${1:- (%s)}" "$c${b##refs/heads/}${f:+ $f}$r"
+		printf "${1:- (%s)}" "$c${b##refs/heads/}${f:+ $f}$r$p"
 	fi
 }
 
-- 
1.7.0.4
Previous: Erik Faye-LundNext: Thomas Rast
Message 13 of 22 in “bash completion: Support "divergence from upstream" warnings in __git_ps1”
  1. 0/2 bash completion: Support "divergence from upstream" warnings in __git_ps1Thomas Rast, Jun 12, 2010
  2. 1/2 rev-list: introduce --count optionThomas Rast, Jun 12, 2010
  3. 2/2 bash completion: Support "divergence from upstream" warnings in __git_ps1Thomas Rast, Jun 12, 2010
  4. Junio C HamanoJun 14, 2010
  5. Thomas RastJun 14, 2010
  6. SZEDER GáborJun 14, 2010
  7. vger doesn't like UTF-8 from send-emailThomas Rast, Jun 12, 2010
  8. send-email: ask about and declare 8bit mailsThomas Rast, Jun 12, 2010
  9. Junio C HamanoJun 12, 2010
  10. Thomas RastJun 13, 2010
  11. Michael WittenJun 13, 2010
  12. Erik Faye-LundJun 14, 2010
  13. bash completion: Support "divergence from upstream" messages in __git_ps1Andrew Sayers, Jun 12, 2010
  14. Thomas RastJun 14, 2010
  15. [PATCHv4] bash completion: Support "divergence from upstream" messages in __git_ps1Andrew Sayers, Jun 15, 2010
  16. Junio C HamanoJun 16, 2010
  17. Thomas RastJun 16, 2010
  18. 0/2 bash completion: Support "divergence from upstream" messages in __git_ps1Andrew Sayers, Jun 17, 2010
  19. Junio C HamanoJun 18, 2010
  20. Andrew SayersJun 18, 2010
  21. 1/2 bash completion: Support "divergence from upstream" messages in __git_ps1Andrew Sayers, Jun 17, 2010
  22. 2/2 bash-completion: Fix __git_ps1 to work with "set -u"Andrew Sayers, Jun 17, 2010

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