refactor: simplify get_current_branch function logic

Refactor the get_current_branch function to improve clarity and maintainability. The updated implementation uses conditional statements to handle directory input more cleanly, eliminating redundancy in the command execution for both specified and current directories.

Author: helizaga

lib/core.sh

@@ -143,11 +143,13 @@ resolve_default_branch() {
 # Usage: get_current_branch [directory]
 # Returns: branch name, "HEAD" if detached, or empty
 get_current_branch() {
-  local dir_flag=""
-  # shellcheck disable=SC2086
-  [ -n "${1:-}" ] && dir_flag="-C $1"
-  git $dir_flag branch --show-current 2>/dev/null ||
-    git $dir_flag rev-parse --abbrev-ref HEAD 2>/dev/null
+  if [ -n "${1:-}" ]; then
+    git -C "$1" branch --show-current 2>/dev/null ||
+      git -C "$1" rev-parse --abbrev-ref HEAD 2>/dev/null
+  else
+    git branch --show-current 2>/dev/null ||
+      git rev-parse --abbrev-ref HEAD 2>/dev/null
+  fi
 }
 
 # Get the current branch of a worktree (with detached HEAD normalization)