fix(powershell): ensure UTF-8 templates are written without BOM (#2280)

* fix(powershell): strip BOM from templates and ensure No-BOM output

* fix: address review feedback on encoding and naming for all ps scripts

* fix: address copilot feedback (encoding detection and variable naming)

* fix: remove duplicate comments in setup-plan.ps1

* test: verify spec.md is written without UTF-8 BOM

* test: also verify BOM-free output under Windows PowerShell 5.1

* fix

* fix: resolve merge conflict with main, add TestDescriptionQuoting

* fix: resolve TestDescriptionQuoting string quoting conflict with main

* test: restore PowerShell prefix-stripping parity test in TestGetFeaturePathsSinglePrefix

* fix: remove trailing whitespace from module docstring blank lines

* Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

* test: seed ps_git_repo with BOM-prefixed template to exercise WriteAllText fix

* fix: remove duplicate ps_git_repo fixture, restore ext_ps_git_repo

* fix: remove unrelated TestDescriptionQuoting and restore original test_ps_specify_feature_prefixed_resolves_by_prefix

---------

Co-authored-by: Nimraakram22 <nimra.akram123451@gmail.com>
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

scripts/powershell/create-new-feature.ps1

@@ -350,7 +350,10 @@ if (-not $DryRun) {
     if (-not (Test-Path -PathType Leaf $specFile)) {
         $template = Resolve-Template -TemplateName 'spec-template' -RepoRoot $repoRoot
         if ($template -and (Test-Path $template)) {
-            Copy-Item $template $specFile -Force
+            # Read the template content and write it to the spec file with UTF-8 encoding without BOM
+            $content = [System.IO.File]::ReadAllText($template)
+            $utf8NoBom = New-Object System.Text.UTF8Encoding($false)
+            [System.IO.File]::WriteAllText($specFile, $content, $utf8NoBom)
         } else {
             New-Item -ItemType File -Path $specFile -Force | Out-Null
         }

scripts/powershell/setup-plan.ps1

@@ -36,8 +36,10 @@ New-Item -ItemType Directory -Path $paths.FEATURE_DIR -Force | Out-Null
 # Copy plan template if it exists, otherwise note it or create empty file
 $template = Resolve-Template -TemplateName 'plan-template' -RepoRoot $paths.REPO_ROOT
 if ($template -and (Test-Path $template)) { 
-    Copy-Item $template $paths.IMPL_PLAN -Force
-    Write-Output "Copied plan template to $($paths.IMPL_PLAN)"
+    # Read the template content and write it to the implementation plan file with UTF-8 encoding without BOM
+    $content = [System.IO.File]::ReadAllText($template)
+    $utf8NoBom = New-Object System.Text.UTF8Encoding($false)
+    [System.IO.File]::WriteAllText($paths.IMPL_PLAN, $content, $utf8NoBom)
 } else {
     Write-Warning "Plan template not found"
     # Create a basic plan file if template doesn't exist

tests/test_timestamp_branches.py

@@ -115,6 +115,36 @@ def ext_ps_git_repo(tmp_path: Path) -> Path:
     return tmp_path
 
 
+@pytest.fixture
+def ps_git_repo(tmp_path: Path) -> Path:
+    """Create a temp git repo with PowerShell scripts and a BOM-prefixed template."""
+    subprocess.run(["git", "init", "-q"], cwd=tmp_path, check=True)
+    subprocess.run(
+        ["git", "config", "user.email", "test@example.com"], cwd=tmp_path, check=True
+    )
+    subprocess.run(
+        ["git", "config", "user.name", "Test User"], cwd=tmp_path, check=True
+    )
+    subprocess.run(
+        ["git", "commit", "--allow-empty", "-m", "init", "-q"],
+        cwd=tmp_path,
+        check=True,
+    )
+    ps_dir = tmp_path / "scripts" / "powershell"
+    ps_dir.mkdir(parents=True)
+    shutil.copy(CREATE_FEATURE_PS, ps_dir / "create-new-feature.ps1")
+    common_ps = PROJECT_ROOT / "scripts" / "powershell" / "common.ps1"
+    shutil.copy(common_ps, ps_dir / "common.ps1")
+    templates_dir = tmp_path / ".specify" / "templates"
+    templates_dir.mkdir(parents=True)
+    # Write a BOM-prefixed template to ensure the WriteAllText fix is actually exercised.
+    # If WriteAllText regresses, the output file will contain the BOM.
+    bom = b"\xef\xbb\xbf"
+    template_content = "# Feature Spec\n\nDescribe the feature here.\n"
+    (templates_dir / "spec-template.md").write_bytes(bom + template_content.encode("utf-8"))
+    return tmp_path
+
+
 @pytest.fixture
 def no_git_dir(tmp_path: Path) -> Path:
     """Create a temp directory without git, but with scripts."""
@@ -381,6 +411,7 @@ class TestGetFeaturePathsSinglePrefix:
         assert result.returncode == 0, result.stderr
         assert result.stdout.strip() == str(tmp_path / "specs" / "001-target-spec")
 
+
     @pytest.mark.skipif(not _has_pwsh(), reason="pwsh not installed")
     def test_ps_specify_feature_prefixed_resolves_by_prefix(self, git_repo: Path):
         """PowerShell Get-FeaturePathsEnv: same prefix stripping as bash."""
@@ -650,6 +681,45 @@ class TestAllowExistingBranchPowerShell:
         assert "$switchBranchError = git checkout -q $branchName 2>&1 | Out-String" in contents
         assert "exists but could not be checked out.`n$($switchBranchError.Trim())" in contents
 
+    @pytest.mark.skipif(not _has_pwsh(), reason="pwsh not installed")
+    @pytest.mark.skipif(
+        os.name != "nt" or shutil.which("powershell.exe") is None,
+        reason="Windows PowerShell not installed",
+    )
+    def test_ps_spec_file_written_without_bom(self, ps_git_repo: Path):
+        """spec.md generated from a BOM-prefixed template must not contain a UTF-8 BOM."""
+        result = subprocess.run(
+            [
+                "powershell.exe",
+                "-NoProfile",
+                "-ExecutionPolicy",
+                "Bypass",
+                "-File",
+                str(CREATE_FEATURE_PS),
+                "-ShortName",
+                "bom-check",
+                "BOM check feature",
+            ],
+            cwd=ps_git_repo,
+            capture_output=True,
+            text=True,
+        )
+        assert result.returncode == 0, result.stderr
+
+        spec_file = next((ps_git_repo / "specs").rglob("spec.md"), None)
+        assert spec_file is not None, (
+            f"spec.md was not created.\nstdout: {result.stdout}\nstderr: {result.stderr}"
+        )
+
+        raw = spec_file.read_bytes()
+        assert not raw.startswith(b"\xef\xbb\xbf"), (
+            f"spec.md must not start with a UTF-8 BOM — got first 3 bytes: {raw[:3]!r}"
+        )
+        # Verify template content was copied (not just an empty New-Item fallback)
+        assert "Feature Spec" in raw.decode("utf-8"), (
+            "spec.md does not contain template content — WriteAllText path was not exercised"
+        )
+
 
 class TestGitExtensionParity:
     def test_bash_extension_surfaces_checkout_errors(self):
@@ -904,30 +974,6 @@ def run_ps_script(cwd: Path, *args: str) -> subprocess.CompletedProcess:
     return subprocess.run(cmd, cwd=cwd, capture_output=True, text=True)
 
 
-@pytest.fixture
-def ps_git_repo(tmp_path: Path) -> Path:
-    """Create a temp git repo with PowerShell scripts and .specify dir."""
-    subprocess.run(["git", "init", "-q"], cwd=tmp_path, check=True)
-    subprocess.run(
-        ["git", "config", "user.email", "test@example.com"], cwd=tmp_path, check=True
-    )
-    subprocess.run(
-        ["git", "config", "user.name", "Test User"], cwd=tmp_path, check=True
-    )
-    subprocess.run(
-        ["git", "commit", "--allow-empty", "-m", "init", "-q"],
-        cwd=tmp_path,
-        check=True,
-    )
-    ps_dir = tmp_path / "scripts" / "powershell"
-    ps_dir.mkdir(parents=True)
-    shutil.copy(CREATE_FEATURE_PS, ps_dir / "create-new-feature.ps1")
-    common_ps = PROJECT_ROOT / "scripts" / "powershell" / "common.ps1"
-    shutil.copy(common_ps, ps_dir / "common.ps1")
-    (tmp_path / ".specify" / "templates").mkdir(parents=True)
-    return tmp_path
-
-
 @pytest.mark.skipif(not _has_pwsh(), reason="pwsh not available")
 class TestPowerShellDryRun:
     def test_ps_dry_run_outputs_name(self, ps_git_repo: Path):
@@ -1259,13 +1305,13 @@ class TestFeatureDirectoryResolution:
             pytest.fail("FEATURE_DIR not found in PowerShell output")
 
 
+
 # ── Description Quoting Tests (issue #2339) ──────────────────────────────────
 
 
 @requires_bash
 class TestDescriptionQuoting:
     """Descriptions with quotes, apostrophes, and backslashes must not break the script.
-
     Regression tests for https://github.com/github/spec-kit/issues/2339
     """
 
@@ -1273,9 +1319,9 @@ class TestDescriptionQuoting:
         "description",
         [
             "Add user's profile page",
-            "Fix the \"login\" bug",
+            'Fix the "login" bug',
             "Handle path\\with\\backslashes",
-            "It's a \"complex\" feature\\here",
+            'It\'s a "complex" feature\\here',
         ],
         ids=["apostrophe", "double-quotes", "backslashes", "mixed"],
     )
@@ -1290,16 +1336,22 @@ class TestDescriptionQuoting:
         "description",
         [
             "Add user's profile page",
-            "Fix the \"login\" bug",
+            'Fix the "login" bug',
             "Handle path\\with\\backslashes",
-            "It's a \"complex\" feature\\here",
+            'It\'s a "complex" feature\\here',
         ],
         ids=["apostrophe", "double-quotes", "backslashes", "mixed"],
     )
     def test_ext_script_handles_special_chars(self, ext_git_repo: Path, description: str):
         """Extension create-new-feature.sh succeeds with special characters in description."""
         script = (
-            ext_git_repo / ".specify" / "extensions" / "git" / "scripts" / "bash" / "create-new-feature.sh"
+            ext_git_repo
+            / ".specify"
+            / "extensions"
+            / "git"
+            / "scripts"
+            / "bash"
+            / "create-new-feature.sh"
         )
         result = subprocess.run(
             ["bash", str(script), "--dry-run", "--short-name", "feat", description],
@@ -1321,3 +1373,4 @@ class TestDescriptionQuoting:
         """Plain description without special characters continues to work."""
         result = run_script(git_repo, "--dry-run", "--short-name", "feat", "Add login feature")
         assert result.returncode == 0, result.stderr
+