Squashed 'gitstatus/' changes from bdaad2e8d..38d35b959

38d35b959 cleanup
7e7b5e807 bash prompt: set PROMPT_COMMAND in a nicer and more robust manner (#403)
7ee9227de Merge branch 'samiam-append_prompt'
198ed58ce Revert "Update README to append to PROMPT_COMMAND"
8b6a229fa Switch to using var assignment for backward compatibility
693f9efa0 Update README to append to PROMPT_COMMAND
a48175ce1 Append to PROMPT_COMMAND to play nice with other prompt programs

git-subtree-dir: gitstatus
git-subtree-split: 38d35b95926e09d07b8cf78edade7cee7a9a1dcf

gitstatus.prompt.sh

@@ -2,7 +2,7 @@
 
 # Source gitstatus.plugin.sh from $GITSTATUS_DIR or from the same directory
 # in which the current script resides if the variable isn't set.
-if [[ -n "${GITSTATUS_DIR:-}" ]]; then
+if [[ -n "${GITSTATUS_DIR-}" ]]; then
   source "$GITSTATUS_DIR"                           || return
 elif [[ "${BASH_SOURCE[0]}" == */* ]]; then
   source "${BASH_SOURCE[0]%/*}/gitstatus.plugin.sh" || return
@@ -85,7 +85,14 @@ function gitstatus_prompt_update() {
 gitstatus_stop && gitstatus_start -s -1 -u -1 -c -1 -d -1
 
 # On every prompt, fetch git status and set GITSTATUS_PROMPT.
-PROMPT_COMMAND=gitstatus_prompt_update
+if [[ -z "${PROMPT_COMMAND[*]}" ]]; then
+  PROMPT_COMMAND=gitstatus_prompt_update
+elif [[ ! "${PROMPT_COMMAND[*]}" =~ [[:space:]\;]?gitstatus_prompt_update[[:space:]\;]? ]]; then
+  # Note: If PROMPT_COMMAND is an array, this will modify its first element.
+  PROMPT_COMMAND=$'gitstatus_prompt_update\n'"$PROMPT_COMMAND"
+fi
+
+# Retain 3 trailing components of the current directory.
 PROMPT_DIRTRIM=3
 
 # Enable promptvars so that ${GITSTATUS_PROMPT} in PS1 is expanded.