Check both stashed and unstashed changes before making auto-stash

We need to perform automatic stash if either unstashed or stashed or
both changes are available.

Author: extsoft

libexec/plugins/pipe

@@ -2,12 +2,20 @@
 # The plugin which allows running a given functions through different types
 # (aka pre- and post-conditions).
 
+has-changes() {
+    # Check if a current index (HEAD) has staged or non-staged changes
+    if git diff-index --quiet HEAD && git diff-index --cached --quiet HEAD; then
+        return 1
+    fi
+    return 0
+}
+
 stash-pipe() {
     # Makes automatic stash and unstash if possible
     # usage:  stash-pipe <command> [args]...
 
     git update-index -q --really-refresh
-    if ! git diff-index --quiet HEAD --; then
+    if has-changes; then
         local message="Elegant Git auto-stash: "
         message+="WIP in '$(git rev-parse --abbrev-ref HEAD)' branch "
         message+="on $(date "+%Y-%m-%dT%H:%M:%S")"