bash-prompt: rewritten not to rely on git status output text

to be error prone to changes in git status command output

diff --git a/bash-prompt.sh b/bash-prompt.sh
index 2750122ee9c0d85fbe34e66277e636a87231a2a0..467e4b372fac0e9dcb21da1860da98a595f7b749 100644 (file)
--- a/bash-prompt.sh
+++ b/bash-prompt.sh
@@ -1,5 +1,5 @@
 # NOTE:
-# This code works known to work for bash
+# This code is known to work with bash
 
 # the code below requires bash 4.x, skip if earlier
 test ${BASH_VERSION%%.*} -lt 4 && return 1
@@ -9,7 +9,7 @@ test ${BASH_VERSION%%.*} -lt 4 && return 1
 
 #
 # A colorized bash prompt
-# - shows curret branch
+# - shows current branch
 # - shows if branch is up to date/ahead/behind
 # - shows if last command exited with error (red)
 #
@@ -43,37 +43,33 @@ __bash_prompt_command() {
 # note we use "\" here to avoid any "git" previous alias/func
 __bash_parse_git_branch() {
        # not in git dir. return early
-       \git rev-parse --git-dir &> /dev/null || return
+       git rev-parse --git-dir &> /dev/null || return
 
-       local git_status branch_pattern remote_pattern diverge_pattern
        local state remote branch
 
-       git_status=$(\git -c color.ui=no status 2> /dev/null)
-       branch_pattern="^On branch ([^${IFS}]*)"
-       remote_pattern="Your branch is (behind|ahead) "
-       diverge_pattern="Your branch and (.*) have diverged"
+       # without branch, nothing is shown; don't bother further
+       branch=$(git symbolic-ref --short HEAD 2>/dev/null) || return
 
-       if [[ ! ${git_status} =~ "working directory clean" ]]; then
+       if [ -n "$(git status -s 2> /dev/null)" ]; then
                state="${RED}★"
        fi
 
-       # add an else if or two here if you want to get more specific
-       if [[ ${git_status} =~ ${remote_pattern} ]]; then
-               if [[ ${BASH_REMATCH[1]} == "ahead" ]]; then
-                       remote="${YELLOW}↑"
-               else
-                       remote="${YELLOW}↓"
-               fi
-       fi
-
-       if [[ ${git_status} =~ ${diverge_pattern} ]]; then
+       # http://stackoverflow.com/a/3278427
+       local=$(git rev-parse @)
+       remote=$(git rev-parse '@{u}')
+       base=$(git merge-base @ '@{u}')
+
+       if [ $local = $remote ]; then
+               remote=""
+       elif [ $local = $base ]; then
+               remote="${YELLOW}↓"
+       elif [ $remote = $base ]; then
+               remote="${YELLOW}↑"
+       else
                remote="${YELLOW}↕"
        fi
 
-       if [[ ${git_status} =~ ${branch_pattern} ]]; then
-               branch=${BASH_REMATCH[1]}
-               echo " (${branch})${remote}${state}"
-       fi
+       echo " (${branch})${remote}${state}"
 }
 
 # cache requires bash 4.x