fix: strip UTF-8 BOM from funcignore and fix negation pattern handling (Azure#7311)

* fix: strip UTF-8 BOM from funcignore and fix negation pattern handling

The go-gitignore library does not handle UTF-8 BOM (byte order mark)
that some Windows editors (e.g. Notepad) prepend to files. When a
.funcignore file has a BOM, the invisible prefix bytes become part of
the first pattern, causing it to never match. This broke the
node_modules exclusion detection in resolveFunctionAppRemoteBuild,
leading to incorrect remoteBuild validation results.

Changes:
- Strip UTF-8 BOM from .funcignore content before parsing in both
  resolveFunctionAppRemoteBuild (validation) and createDeployableZip
  (packaging) for consistent behavior
- Switch createDeployableZip from gitignore.NewFromFile to manual
  read + gitignore.New for consistency with validation code path
- Fix negation pattern handling in createDeployableZip: check
  match.Ignore() instead of just match != nil, so negation patterns
  (e.g. !node_modules/important) correctly include files
- Add comprehensive BOM-handling tests and stripUTF8BOM unit tests

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: clean up temp zip file on ignore file read error

Close and remove the temporary zip file when reading the ignore file
fails with a non-NotExist error, preventing file handle leaks and
orphaned temp files (especially on Windows).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* ci: retrigger CI (Windows extension test flake)

The previous Windows BuildCLI failure was a known file-locking flake in
Test_CLI_Extension_ForceInstall — unrelated to this PR's changes.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* refactor: merge CustomerScenarios into JavaScriptMatrix test

Addresses review feedback from @weikanglim. The CustomerScenarios test
was duplicating 8 of 9 cases from JavaScriptMatrix. Merged Case 9
(true + no funcignore) into JavaScriptMatrix and added customer case
comments for traceability. Removed the duplicate test function.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jongio

cli/azd/pkg/project/project_utils.go

@@ -4,6 +4,7 @@
 package project
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"io/fs"
@@ -30,12 +31,19 @@ func createDeployableZip(svc *ServiceConfig, root string) (string, error) {
 	ignoreFile := svc.Host.IgnoreFile()
 	var ignorer gitignore.GitIgnore
 	if ignoreFile != "" {
-		ig, err := gitignore.NewFromFile(filepath.Join(root, ignoreFile))
-		if !errors.Is(err, fs.ErrNotExist) && err != nil {
+		ignoreFilePath := filepath.Join(root, ignoreFile)
+		contents, err := os.ReadFile(ignoreFilePath)
+		if errors.Is(err, fs.ErrNotExist) {
+			// no ignore file, use defaults below
+		} else if err != nil {
+			zipFile.Close()
+			os.Remove(zipFile.Name()) //nolint:gosec // G703: zipFile.Name() is our own temp file, not user-controlled
 			return "", fmt.Errorf("reading ignore file: %w", err)
+		} else {
+			// Strip UTF-8 BOM if present, then parse from in-memory contents.
+			contents = stripUTF8BOM(contents)
+			ignorer = gitignore.New(bytes.NewReader(contents), root, nil)
 		}
-
-		ignorer = ig
 	}
 
 	// apply exclusions for zip deployment
@@ -68,9 +76,11 @@ func createDeployableZip(svc *ServiceConfig, root string) (string, error) {
 		}
 
 		// apply exclusions from ignore file
-		if ignorer != nil && ignorer.Absolute(src, isDir) != nil {
-			return false, nil
-		} else if ignorer == nil { // default exclusions without ignorefile control
+		if ignorer != nil {
+			if match := ignorer.Absolute(src, isDir); match != nil && match.Ignore() {
+				return false, nil
+			}
+		} else { // default exclusions without ignorefile control
 			if svc.Language == ServiceLanguagePython {
 				if isDir {
 					// check for .venv containing pyvenv.cfg
@@ -112,3 +122,12 @@ func createDeployableZip(svc *ServiceConfig, root string) (string, error) {
 
 	return zipFile.Name(), nil
 }
+
+// utf8BOM is the byte order mark that some Windows editors prepend to UTF-8 files.
+var utf8BOM = []byte{0xEF, 0xBB, 0xBF}
+
+// stripUTF8BOM removes a leading UTF-8 BOM from the given byte slice if present.
+// The BOM breaks gitignore pattern parsing because the invisible bytes become part of the first pattern.
+func stripUTF8BOM(data []byte) []byte {
+	return bytes.TrimPrefix(data, utf8BOM)
+}

cli/azd/pkg/project/service_target_functionapp.go

@@ -44,6 +44,11 @@ func resolveFunctionAppRemoteBuild(serviceConfig *ServiceConfig) (remoteBuild bo
 			return false, fmt.Errorf("reading ignore file: %w", err)
 		}
 
+		// Strip UTF-8 BOM if present. Some Windows editors (e.g. Notepad) prepend a BOM which
+		// causes the gitignore parser to treat the first pattern as having invisible prefix bytes,
+		// breaking pattern matching.
+		ignoreFileContents = stripUTF8BOM(ignoreFileContents)
+
 		// Parse from in-memory contents so we don't hold an open file handle (important on Windows temp dirs).
 		ignore := gitignore.New(bytes.NewReader(ignoreFileContents), serviceConfig.Path(), nil)