Use the number prefix to find the right spec

scripts/bash/common.sh

@@ -19,21 +19,21 @@ get_current_branch() {
         echo "$SPECIFY_FEATURE"
         return
     fi
-    
+
     # Then check git if available
     if git rev-parse --abbrev-ref HEAD >/dev/null 2>&1; then
         git rev-parse --abbrev-ref HEAD
         return
     fi
-    
+
     # For non-git repos, try to find the latest feature directory
     local repo_root=$(get_repo_root)
     local specs_dir="$repo_root/specs"
-    
+
     if [[ -d "$specs_dir" ]]; then
         local latest_feature=""
         local highest=0
-        
+
         for dir in "$specs_dir"/*; do
             if [[ -d "$dir" ]]; then
                 local dirname=$(basename "$dir")
@@ -47,13 +47,13 @@ get_current_branch() {
                 fi
             fi
         done
-        
+
         if [[ -n "$latest_feature" ]]; then
             echo "$latest_feature"
             return
         fi
     fi
-    
+
     echo "main"  # Final fallback
 }
 
@@ -65,35 +65,77 @@ has_git() {
 check_feature_branch() {
     local branch="$1"
     local has_git_repo="$2"
-    
+
     # For non-git repos, we can't enforce branch naming but still provide output
     if [[ "$has_git_repo" != "true" ]]; then
         echo "[specify] Warning: Git repository not detected; skipped branch validation" >&2
         return 0
     fi
-    
+
     if [[ ! "$branch" =~ ^[0-9]{3}- ]]; then
         echo "ERROR: Not on a feature branch. Current branch: $branch" >&2
         echo "Feature branches should be named like: 001-feature-name" >&2
         return 1
     fi
-    
+
     return 0
 }
 
 get_feature_dir() { echo "$1/specs/$2"; }
 
+# Find feature directory by numeric prefix instead of exact branch match
+# This allows multiple branches to work on the same spec (e.g., 004-fix-bug, 004-add-feature)
+find_feature_dir_by_prefix() {
+    local repo_root="$1"
+    local branch_name="$2"
+    local specs_dir="$repo_root/specs"
+
+    # Extract numeric prefix from branch (e.g., "004" from "004-whatever")
+    if [[ ! "$branch_name" =~ ^([0-9]{3})- ]]; then
+        # If branch doesn't have numeric prefix, fall back to exact match
+        echo "$specs_dir/$branch_name"
+        return
+    fi
+
+    local prefix="${BASH_REMATCH[1]}"
+
+    # Search for directories in specs/ that start with this prefix
+    local matches=()
+    if [[ -d "$specs_dir" ]]; then
+        for dir in "$specs_dir"/"$prefix"-*; do
+            if [[ -d "$dir" ]]; then
+                matches+=("$(basename "$dir")")
+            fi
+        done
+    fi
+
+    # Handle results
+    if [[ ${#matches[@]} -eq 0 ]]; then
+        # No match found - return the branch name path (will fail later with clear error)
+        echo "$specs_dir/$branch_name"
+    elif [[ ${#matches[@]} -eq 1 ]]; then
+        # Exactly one match - perfect!
+        echo "$specs_dir/${matches[0]}"
+    else
+        # Multiple matches - this shouldn't happen with proper naming convention
+        echo "ERROR: Multiple spec directories found with prefix '$prefix': ${matches[*]}" >&2
+        echo "Please ensure only one spec directory exists per numeric prefix." >&2
+        echo "$specs_dir/$branch_name"  # Return something to avoid breaking the script
+    fi
+}
+
 get_feature_paths() {
     local repo_root=$(get_repo_root)
     local current_branch=$(get_current_branch)
     local has_git_repo="false"
-    
+
     if has_git; then
         has_git_repo="true"
     fi
-    
-    local feature_dir=$(get_feature_dir "$repo_root" "$current_branch")
-    
+
+    # Use prefix-based lookup to support multiple branches per spec
+    local feature_dir=$(find_feature_dir_by_prefix "$repo_root" "$current_branch")
+
     cat <<EOF
 REPO_ROOT='$repo_root'
 CURRENT_BRANCH='$current_branch'