fix: address code review feedback

- Normalize paths in find_specify_root to prevent infinite loop with relative paths
- Use -PathType Container in PowerShell to only match .specify directories
- Improve has_git/Test-HasGit to check git command availability and validate work tree
- Handle git worktrees/submodules where .git can be a file
- Remove dead fallback code in create-new-feature scripts

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: iamaeroplane

scripts/bash/common.sh

@@ -5,11 +5,15 @@
 # This is the primary marker for spec-kit projects
 find_specify_root() {
     local dir="${1:-$(pwd)}"
-    while [ "$dir" != "/" ]; do
+    # Normalize to absolute path to prevent infinite loop with relative paths
+    dir="$(cd "$dir" 2>/dev/null && pwd)" || return 1
+    local prev_dir=""
+    while [ "$dir" != "/" ] && [ "$dir" != "$prev_dir" ]; do
         if [ -d "$dir/.specify" ]; then
             echo "$dir"
             return 0
         fi
+        prev_dir="$dir"
         dir="$(dirname "$dir")"
     done
     return 1
@@ -82,10 +86,16 @@ get_current_branch() {
 }
 
 # Check if we have git available at the spec-kit root level
-# Returns true only if the .specify root has its own .git directory
+# Returns true only if git is installed and the repo root is inside a git work tree
+# Handles both regular repos (.git directory) and worktrees/submodules (.git file)
 has_git() {
     local repo_root=$(get_repo_root)
-    [ -d "$repo_root/.git" ]
+    # First check if git command is available
+    command -v git >/dev/null 2>&1 || return 1
+    # Check if .git exists (directory or file for worktrees/submodules)
+    [ -e "$repo_root/.git" ] || return 1
+    # Verify it's actually a valid git work tree
+    git -C "$repo_root" rev-parse --is-inside-work-tree >/dev/null 2>&1
 }
 
 check_feature_branch() {

scripts/bash/create-new-feature.sh

@@ -167,14 +167,6 @@ SCRIPT_DIR="$(CDPATH="" cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 source "$SCRIPT_DIR/common.sh"
 
 REPO_ROOT=$(get_repo_root)
-if [ -z "$REPO_ROOT" ]; then
-    # Fallback to local find_repo_root if common.sh couldn't find it
-    REPO_ROOT="$(find_repo_root "$SCRIPT_DIR")"
-    if [ -z "$REPO_ROOT" ]; then
-        echo "Error: Could not determine repository root. Please run this script from within the repository." >&2
-        exit 1
-    fi
-fi
 
 # Check if git is available at this repo root (not a parent)
 if has_git; then

scripts/powershell/common.ps1

@@ -6,9 +6,12 @@
 function Find-SpecifyRoot {
     param([string]$StartDir = (Get-Location).Path)
 
-    $current = $StartDir
+    # Normalize to absolute path to prevent issues with relative paths
+    $current = (Resolve-Path $StartDir -ErrorAction SilentlyContinue)?.Path
+    if (-not $current) { return $null }
+
     while ($true) {
-        if (Test-Path (Join-Path $current ".specify")) {
+        if (Test-Path -Path (Join-Path $current ".specify") -PathType Container) {
             return $current
         }
         $parent = Split-Path $current -Parent
@@ -86,10 +89,25 @@ function Get-CurrentBranch {
 }
 
 # Check if we have git available at the spec-kit root level
-# Returns true only if the .specify root has its own .git directory
+# Returns true only if git is installed and the repo root is inside a git work tree
+# Handles both regular repos (.git directory) and worktrees/submodules (.git file)
 function Test-HasGit {
     $repoRoot = Get-RepoRoot
-    return (Test-Path (Join-Path $repoRoot ".git"))
+    # First check if git command is available
+    if (-not (Get-Command git -ErrorAction SilentlyContinue)) {
+        return $false
+    }
+    # Check if .git exists (directory or file for worktrees/submodules)
+    if (-not (Test-Path (Join-Path $repoRoot ".git"))) {
+        return $false
+    }
+    # Verify it's actually a valid git work tree
+    try {
+        $null = git -C $repoRoot rev-parse --is-inside-work-tree 2>$null
+        return ($LASTEXITCODE -eq 0)
+    } catch {
+        return $false
+    }
 }
 
 function Test-FeatureBranch {

scripts/powershell/create-new-feature.ps1

@@ -140,14 +140,6 @@ function ConvertTo-CleanBranchName {
 
 # Use common.ps1 functions which prioritize .specify over git
 $repoRoot = Get-RepoRoot
-if (-not $repoRoot) {
-    # Fallback to local Find-RepositoryRoot if common.ps1 couldn't find it
-    $repoRoot = (Find-RepositoryRoot -StartDir $PSScriptRoot)
-    if (-not $repoRoot) {
-        Write-Error "Error: Could not determine repository root. Please run this script from within the repository."
-        exit 1
-    }
-}
 
 # Check if git is available at this repo root (not a parent)
 $hasGit = Test-HasGit