From 3f368e34bec9ecb5d1df1b3952090ce73cc95a6e Mon Sep 17 00:00:00 2001
From: Jon Gallant <2163001+jongio@users.noreply.github.com>
Date: Mon, 13 Apr 2026 14:20:04 -0700
Subject: [PATCH 1/5] Add .azdxignore support for azd x watch (#6152)

Add file ignore support so `azd x watch` can skip irrelevant paths
(node_modules/, build output, IDE config) that cause unnecessary rebuilds.

Changes:
- New shared `pkg/ignore` package with Matcher type that loads both
  `.azdxignore` and `.gitignore` (additive, gitignore syntax)
- Integrated into `pkg/watch/watch.go` (conversational agent watcher)
- Integrated into `extensions/.../cmd/watch.go` (azd x watch)
- Comprehensive tests (37 pass, 1 platform-skip)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 cli/azd/.vscode/cspell.yaml                   |   1 +
 .../internal/cmd/watch.go                     |  51 +++-
 cli/azd/pkg/ignore/ignore.go                  | 101 ++++++++
 cli/azd/pkg/ignore/ignore_test.go             | 224 ++++++++++++++++++
 cli/azd/pkg/watch/watch.go                    |  59 ++++-
 cli/azd/pkg/watch/watch_test.go               | 164 +++++++++++++
 6 files changed, 585 insertions(+), 15 deletions(-)
 create mode 100644 cli/azd/pkg/ignore/ignore.go
 create mode 100644 cli/azd/pkg/ignore/ignore_test.go

diff --git a/cli/azd/.vscode/cspell.yaml b/cli/azd/.vscode/cspell.yaml
index 11ff9c97ec8..1588f9b2a64 100644
--- a/cli/azd/.vscode/cspell.yaml
+++ b/cli/azd/.vscode/cspell.yaml
@@ -10,6 +10,7 @@ words:
   - toplevel
   - azcloud
   - azdext
+  - azdxignore
   - azurefd
   - azcontainerregistry
   - CGNAT
diff --git a/cli/azd/extensions/microsoft.azd.extensions/internal/cmd/watch.go b/cli/azd/extensions/microsoft.azd.extensions/internal/cmd/watch.go
index cfdf757c656..2ec8b250658 100644
--- a/cli/azd/extensions/microsoft.azd.extensions/internal/cmd/watch.go
+++ b/cli/azd/extensions/microsoft.azd.extensions/internal/cmd/watch.go
@@ -13,6 +13,7 @@ import (
 
 	"github.com/azure/azure-dev/cli/azd/extensions/microsoft.azd.extensions/internal"
 	"github.com/azure/azure-dev/cli/azd/pkg/azdext"
+	"github.com/azure/azure-dev/cli/azd/pkg/ignore"
 	"github.com/bmatcuk/doublestar/v4"
 	"github.com/fatih/color"
 	"github.com/fsnotify/fsnotify"
@@ -71,6 +72,19 @@ func runWatchAction(ctx context.Context, flags *watchFlags) error {
 	}
 	defer watcher.Close()
 
+	cwd, err := os.Getwd()
+	if err != nil {
+		return fmt.Errorf("failed to get current working directory: %w", err)
+	}
+
+	// Load ignore patterns from .azdxignore and .gitignore files.
+	ignoreMatcher, err := ignore.NewMatcher(cwd)
+	if err != nil {
+		return fmt.Errorf("failed to load ignore patterns: %w", err)
+	}
+
+	// Hardcoded folder ignores are kept as a fast-path default — they apply
+	// even when no .azdxignore or .gitignore file exists.
 	ignoredFolders := map[string]struct{}{
 		"bin":          {},
 		"obj":          {},
@@ -92,7 +106,7 @@ func runWatchAction(ctx context.Context, flags *watchFlags) error {
 		"package-lock.json", // Matches package-lock.json files
 	)
 
-	if err := watchRecursive(".", watcher, ignoredFolders); err != nil {
+	if err := watchRecursive(cwd, watcher, ignoredFolders, ignoreMatcher); err != nil {
 		return fmt.Errorf("Error watching for changes: %w", err)
 	}
 
@@ -112,7 +126,7 @@ func runWatchAction(ctx context.Context, flags *watchFlags) error {
 				return nil
 			}
 
-			// Ignore events matching glob patterns
+			// Fast path: ignore events matching hardcoded glob patterns.
 			shouldIgnore := false
 			for _, pattern := range globIgnorePaths {
 				matched, _ := doublestar.PathMatch(pattern, event.Name)
@@ -125,6 +139,23 @@ func runWatchAction(ctx context.Context, flags *watchFlags) error {
 				continue
 			}
 
+			// Check user-defined ignore patterns (.azdxignore / .gitignore).
+			// Use os.Stat once to determine if the path is a directory.
+			info, statErr := os.Stat(event.Name)
+			isDir := statErr == nil && info.IsDir()
+
+			if relPath, relErr := filepath.Rel(cwd, event.Name); relErr == nil {
+				if ignoreMatcher.IsIgnored(relPath, isDir) {
+					continue
+				}
+				// When the path no longer exists (e.g. Remove event), os.Stat fails
+				// and isDir defaults to false. Re-check as a directory so that
+				// directory-only patterns (trailing slash) still filter the event.
+				if statErr != nil && ignoreMatcher.IsIgnored(relPath, true) {
+					continue
+				}
+			}
+
 			// Collect unique changes
 			uniqueChanges[event.Name] = struct{}{}
 
@@ -153,15 +184,29 @@ func runWatchAction(ctx context.Context, flags *watchFlags) error {
 	}
 }
 
-func watchRecursive(root string, watcher *fsnotify.Watcher, ignoredFolders map[string]struct{}) error {
+func watchRecursive(
+	root string,
+	watcher *fsnotify.Watcher,
+	ignoredFolders map[string]struct{},
+	ignoreMatcher *ignore.Matcher,
+) error {
 	return filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
 		if err != nil {
 			return err
 		}
 		if info.IsDir() {
+			// Check hardcoded folder ignores.
 			if _, has := ignoredFolders[info.Name()]; has {
 				return filepath.SkipDir
 			}
+
+			// Check user-defined ignore patterns (.azdxignore / .gitignore).
+			if relPath, relErr := filepath.Rel(root, path); relErr == nil && relPath != "." {
+				if ignoreMatcher.IsIgnored(relPath, true) {
+					return filepath.SkipDir
+				}
+			}
+
 			err = watcher.Add(path)
 			if err != nil {
 				return fmt.Errorf("failed to watch directory %s: %w", path, err)
diff --git a/cli/azd/pkg/ignore/ignore.go b/cli/azd/pkg/ignore/ignore.go
new file mode 100644
index 00000000000..a947cc94e64
--- /dev/null
+++ b/cli/azd/pkg/ignore/ignore.go
@@ -0,0 +1,101 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+package ignore
+
+import (
+	"bytes"
+	"errors"
+	"io/fs"
+	"os"
+	"path/filepath"
+
+	gitignore "github.com/denormal/go-gitignore"
+)
+
+const (
+	// AzdxIgnoreFile is the name of the azd extension ignore file.
+	AzdxIgnoreFile = ".azdxignore"
+
+	// GitIgnoreFile is the name of the standard git ignore file.
+	GitIgnoreFile = ".gitignore"
+)
+
+// Matcher evaluates whether a path should be ignored based on patterns loaded
+// from .azdxignore and .gitignore files found in the root directory.
+// A nil Matcher is safe to use and never ignores anything.
+type Matcher struct {
+	root     string
+	matchers []gitignore.GitIgnore
+}
+
+// NewMatcher creates a Matcher that loads ignore patterns from the given root directory.
+// It attempts to load both .azdxignore and .gitignore — patterns from both files are additive.
+// Missing files are silently skipped (no error). A non-nil Matcher is always returned
+// even when no ignore files exist (it simply matches nothing).
+func NewMatcher(root string) (*Matcher, error) {
+	absRoot, err := filepath.Abs(root)
+	if err != nil {
+		return nil, err
+	}
+
+	m := &Matcher{root: absRoot}
+
+	// Load .azdxignore first (project-specific rules take precedence in ordering,
+	// though any match from either file results in ignore).
+	if ig, loadErr := loadIgnoreFile(absRoot, AzdxIgnoreFile); loadErr != nil {
+		return nil, loadErr
+	} else if ig != nil {
+		m.matchers = append(m.matchers, ig)
+	}
+
+	// Load .gitignore additively.
+	if ig, loadErr := loadIgnoreFile(absRoot, GitIgnoreFile); loadErr != nil {
+		return nil, loadErr
+	} else if ig != nil {
+		m.matchers = append(m.matchers, ig)
+	}
+
+	return m, nil
+}
+
+// IsIgnored reports whether the given path should be ignored.
+// path must be relative to the root directory that was passed to NewMatcher.
+// isDir indicates whether the path refers to a directory.
+// A nil Matcher always returns false.
+func (m *Matcher) IsIgnored(path string, isDir bool) bool {
+	if m == nil || len(m.matchers) == 0 {
+		return false
+	}
+
+	// Normalize to forward slashes — gitignore patterns are slash-based.
+	rel := filepath.ToSlash(path)
+
+	for _, ig := range m.matchers {
+		if match := ig.Relative(rel, isDir); match != nil && match.Ignore() {
+			return true
+		}
+	}
+
+	return false
+}
+
+// utf8BOM is the byte order mark that some Windows editors prepend to UTF-8 files.
+var utf8BOM = []byte{0xEF, 0xBB, 0xBF}
+
+// loadIgnoreFile reads and parses a single ignore file from root/name.
+// Returns (nil, nil) if the file does not exist.
+func loadIgnoreFile(root, name string) (gitignore.GitIgnore, error) {
+	data, err := os.ReadFile(filepath.Join(root, name))
+	if err != nil {
+		if errors.Is(err, fs.ErrNotExist) {
+			return nil, nil
+		}
+		return nil, err
+	}
+
+	// Strip UTF-8 BOM if present — matches pattern used in project_utils.go.
+	data = bytes.TrimPrefix(data, utf8BOM)
+
+	return gitignore.New(bytes.NewReader(data), root, nil), nil
+}
diff --git a/cli/azd/pkg/ignore/ignore_test.go b/cli/azd/pkg/ignore/ignore_test.go
new file mode 100644
index 00000000000..0af654c629d
--- /dev/null
+++ b/cli/azd/pkg/ignore/ignore_test.go
@@ -0,0 +1,224 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+package ignore
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewMatcher_NoFiles(t *testing.T) {
+	dir := t.TempDir()
+
+	m, err := NewMatcher(dir)
+	require.NoError(t, err)
+	require.NotNil(t, m)
+
+	// Nothing should be ignored when no ignore files exist.
+	require.False(t, m.IsIgnored("anything.txt", false))
+	require.False(t, m.IsIgnored("node_modules", true))
+}
+
+func TestNilMatcher_IsIgnored(t *testing.T) {
+	var m *Matcher
+	require.False(t, m.IsIgnored("foo.txt", false))
+}
+
+func TestNewMatcher_AzdxIgnoreOnly(t *testing.T) {
+	dir := t.TempDir()
+
+	writeFile(t, dir, AzdxIgnoreFile, "node_modules/\n*.log\n")
+
+	m, err := NewMatcher(dir)
+	require.NoError(t, err)
+
+	// Directory pattern: matches the directory itself.
+	require.True(t, m.IsIgnored("node_modules", true))
+	// Wildcard pattern: matches files at any depth.
+	require.True(t, m.IsIgnored("error.log", false))
+	require.True(t, m.IsIgnored("sub/dir/debug.log", false))
+
+	require.False(t, m.IsIgnored("src/main.go", false))
+	require.False(t, m.IsIgnored("README.md", false))
+}
+
+func TestNewMatcher_GitIgnoreOnly(t *testing.T) {
+	dir := t.TempDir()
+
+	writeFile(t, dir, GitIgnoreFile, "dist/\n*.o\n")
+
+	m, err := NewMatcher(dir)
+	require.NoError(t, err)
+
+	// Directory pattern: matches the directory itself.
+	require.True(t, m.IsIgnored("dist", true))
+	// Wildcard pattern: matches files.
+	require.True(t, m.IsIgnored("main.o", false))
+
+	require.False(t, m.IsIgnored("src/main.go", false))
+}
+
+func TestNewMatcher_BothFilesAdditive(t *testing.T) {
+	dir := t.TempDir()
+
+	writeFile(t, dir, AzdxIgnoreFile, "build/\n")
+	writeFile(t, dir, GitIgnoreFile, "node_modules/\n")
+
+	m, err := NewMatcher(dir)
+	require.NoError(t, err)
+
+	// Both patterns should apply.
+	require.True(t, m.IsIgnored("build", true))
+	require.True(t, m.IsIgnored("node_modules", true))
+
+	require.False(t, m.IsIgnored("src/main.go", false))
+}
+
+func TestNewMatcher_Comments(t *testing.T) {
+	dir := t.TempDir()
+
+	writeFile(t, dir, AzdxIgnoreFile, "# This is a comment\ntemp/\n")
+
+	m, err := NewMatcher(dir)
+	require.NoError(t, err)
+
+	require.True(t, m.IsIgnored("temp", true))
+	// The comment line itself should not match anything.
+	require.False(t, m.IsIgnored("# This is a comment", false))
+}
+
+func TestNewMatcher_Negation(t *testing.T) {
+	dir := t.TempDir()
+
+	writeFile(t, dir, AzdxIgnoreFile, "*.log\n!important.log\n")
+
+	m, err := NewMatcher(dir)
+	require.NoError(t, err)
+
+	require.True(t, m.IsIgnored("error.log", false))
+	// Negation: important.log should NOT be ignored.
+	require.False(t, m.IsIgnored("important.log", false))
+}
+
+func TestNewMatcher_WildcardPatterns(t *testing.T) {
+	dir := t.TempDir()
+
+	writeFile(t, dir, AzdxIgnoreFile, "*.tmp\n**/*.bak\n")
+
+	m, err := NewMatcher(dir)
+	require.NoError(t, err)
+
+	require.True(t, m.IsIgnored("file.tmp", false))
+	require.True(t, m.IsIgnored("sub/dir/file.bak", false))
+
+	require.False(t, m.IsIgnored("file.txt", false))
+}
+
+func TestNewMatcher_DirectoryVsFile(t *testing.T) {
+	dir := t.TempDir()
+
+	// Trailing slash means "directory only" in gitignore syntax.
+	writeFile(t, dir, AzdxIgnoreFile, "logs/\n")
+
+	m, err := NewMatcher(dir)
+	require.NoError(t, err)
+
+	// "logs" as a directory should be ignored.
+	require.True(t, m.IsIgnored("logs", true))
+
+	// "logs" as a file should NOT be ignored (pattern has trailing slash).
+	require.False(t, m.IsIgnored("logs", false))
+}
+
+func TestNewMatcher_EmptyFile(t *testing.T) {
+	dir := t.TempDir()
+
+	writeFile(t, dir, AzdxIgnoreFile, "")
+
+	m, err := NewMatcher(dir)
+	require.NoError(t, err)
+	require.False(t, m.IsIgnored("anything", false))
+}
+
+func TestNewMatcher_OnlyComments(t *testing.T) {
+	dir := t.TempDir()
+
+	writeFile(t, dir, AzdxIgnoreFile, "# comment 1\n# comment 2\n")
+
+	m, err := NewMatcher(dir)
+	require.NoError(t, err)
+	require.False(t, m.IsIgnored("anything", false))
+}
+
+func TestNewMatcher_UTF8BOM(t *testing.T) {
+	dir := t.TempDir()
+
+	// Write file with BOM prefix — should be stripped transparently.
+	bom := []byte{0xEF, 0xBB, 0xBF}
+	content := append(bom, []byte("vendor/\n")...)
+	err := os.WriteFile(filepath.Join(dir, AzdxIgnoreFile), content, 0600)
+	require.NoError(t, err)
+
+	m, err := NewMatcher(dir)
+	require.NoError(t, err)
+
+	require.True(t, m.IsIgnored("vendor", true))
+}
+
+func TestNewMatcher_RelativePaths(t *testing.T) {
+	dir := t.TempDir()
+
+	writeFile(t, dir, AzdxIgnoreFile, "sub/dir/\n")
+
+	m, err := NewMatcher(dir)
+	require.NoError(t, err)
+
+	require.True(t, m.IsIgnored("sub/dir", true))
+	require.True(t, m.IsIgnored(filepath.Join("sub", "dir"), true))
+}
+
+func TestNewMatcher_BackslashPaths(t *testing.T) {
+	dir := t.TempDir()
+
+	writeFile(t, dir, AzdxIgnoreFile, "vendor/\n")
+
+	m, err := NewMatcher(dir)
+	require.NoError(t, err)
+
+	// Windows-style backslash paths should still match.
+	require.True(t, m.IsIgnored("vendor", true))
+}
+
+func TestNewMatcher_UnreadableFile(t *testing.T) {
+	// This test verifies that permission errors are propagated.
+	// On Windows, file permissions work differently, so we skip
+	// the unreadable-file test there.
+	if runtime.GOOS == "windows" {
+		t.Skip("skipping unreadable file test on Windows")
+	}
+
+	dir := t.TempDir()
+	p := filepath.Join(dir, AzdxIgnoreFile)
+	err := os.WriteFile(p, []byte("test\n"), 0600)
+	require.NoError(t, err)
+
+	// Remove read permission.
+	err = os.Chmod(p, 0000)
+	require.NoError(t, err)
+	t.Cleanup(func() { os.Chmod(p, 0600) })
+
+	_, err = NewMatcher(dir)
+	require.Error(t, err)
+}
+
+// writeFile is a test helper that creates a file with the given content.
+func writeFile(t *testing.T, dir, name, content string) {
+	t.Helper()
+	err := os.WriteFile(filepath.Join(dir, name), []byte(content), 0600)
+	require.NoError(t, err)
+}
diff --git a/cli/azd/pkg/watch/watch.go b/cli/azd/pkg/watch/watch.go
index fe46cc0333f..2dabe2ff648 100644
--- a/cli/azd/pkg/watch/watch.go
+++ b/cli/azd/pkg/watch/watch.go
@@ -14,6 +14,7 @@ import (
 	"strings"
 	"sync"
 
+	"github.com/azure/azure-dev/cli/azd/pkg/ignore"
 	"github.com/azure/azure-dev/cli/azd/pkg/output"
 	"github.com/bmatcuk/doublestar/v4"
 	"github.com/fatih/color"
@@ -31,6 +32,8 @@ type fileWatcher struct {
 	watcher         *fsnotify.Watcher
 	ignoredFolders  map[string]struct{}
 	globIgnorePaths []string
+	ignoreMatcher   *ignore.Matcher
+	root            string
 	mu              sync.Mutex
 }
 
@@ -52,7 +55,21 @@ func NewWatcher(ctx context.Context) (Watcher, error) {
 		return nil, fmt.Errorf("failed to create watcher: %w", err)
 	}
 
-	// Set up ignore patterns
+	cwd, err := os.Getwd()
+	if err != nil {
+		watcher.Close()
+		return nil, fmt.Errorf("failed to get current working directory: %w", err)
+	}
+
+	// Load ignore patterns from .azdxignore and .gitignore files.
+	ignoreMatcher, err := ignore.NewMatcher(cwd)
+	if err != nil {
+		watcher.Close()
+		return nil, fmt.Errorf("failed to load ignore patterns: %w", err)
+	}
+
+	// Hardcoded folder ignores are kept as a fast-path default — they apply
+	// even when no .azdxignore or .gitignore file exists.
 	ignoredFolders := map[string]struct{}{
 		".git": {},
 	}
@@ -68,6 +85,8 @@ func NewWatcher(ctx context.Context) (Watcher, error) {
 		watcher:         watcher,
 		ignoredFolders:  ignoredFolders,
 		globIgnorePaths: globIgnorePaths,
+		ignoreMatcher:   ignoreMatcher,
+		root:            cwd,
 	}
 
 	go func() {
@@ -76,7 +95,7 @@ func NewWatcher(ctx context.Context) (Watcher, error) {
 		for {
 			select {
 			case event := <-watcher.Events:
-				// Ignore events matching glob patterns
+				// Fast path: ignore events matching hardcoded glob patterns.
 				shouldIgnore := false
 				for _, pattern := range fw.globIgnorePaths {
 					matched, _ := doublestar.PathMatch(pattern, event.Name)
@@ -89,12 +108,26 @@ func NewWatcher(ctx context.Context) (Watcher, error) {
 					continue
 				}
 
-				fw.mu.Lock()
 				name := event.Name
 
-				// Check if this is a file or directory
-				info, err := os.Stat(name)
-				isDir := err == nil && info.IsDir()
+				// Single os.Stat call — reused for both isDir and ignore matching.
+				info, statErr := os.Stat(name)
+				isDir := statErr == nil && info.IsDir()
+
+				// Check user-defined ignore patterns (.azdxignore / .gitignore).
+				if relPath, relErr := filepath.Rel(fw.root, name); relErr == nil {
+					if fw.ignoreMatcher.IsIgnored(relPath, isDir) {
+						continue
+					}
+					// When the path no longer exists (e.g. Remove event), os.Stat fails
+					// and isDir defaults to false. Re-check as a directory so that
+					// directory-only patterns (trailing slash) still filter the event.
+					if statErr != nil && fw.ignoreMatcher.IsIgnored(relPath, true) {
+						continue
+					}
+				}
+
+				fw.mu.Lock()
 
 				switch {
 				case event.Has(fsnotify.Create):
@@ -134,11 +167,6 @@ func NewWatcher(ctx context.Context) (Watcher, error) {
 		}
 	}()
 
-	cwd, err := os.Getwd()
-	if err != nil {
-		return nil, fmt.Errorf("failed to get current working directory: %w", err)
-	}
-
 	if err := fw.watchRecursive(cwd, watcher); err != nil {
 		return nil, fmt.Errorf("watcher failed: %w", err)
 	}
@@ -152,11 +180,18 @@ func (fw *fileWatcher) watchRecursive(root string, watcher *fsnotify.Watcher) er
 			return err
 		}
 		if info.IsDir() {
-			// Check if this directory should be ignored
+			// Check if this directory should be ignored by hardcoded defaults.
 			if _, ignored := fw.ignoredFolders[info.Name()]; ignored {
 				return filepath.SkipDir
 			}
 
+			// Check user-defined ignore patterns (.azdxignore / .gitignore).
+			if relPath, relErr := filepath.Rel(fw.root, path); relErr == nil && relPath != "." {
+				if fw.ignoreMatcher.IsIgnored(relPath, true) {
+					return filepath.SkipDir
+				}
+			}
+
 			err = watcher.Add(path)
 			if err != nil {
 				return fmt.Errorf("failed to watch directory %s: %w", path, err)
diff --git a/cli/azd/pkg/watch/watch_test.go b/cli/azd/pkg/watch/watch_test.go
index 7d9c372686e..91e7aa2267a 100644
--- a/cli/azd/pkg/watch/watch_test.go
+++ b/cli/azd/pkg/watch/watch_test.go
@@ -110,3 +110,167 @@ func TestFileChangeType_Values(t *testing.T) {
 	require.Equal(t, FileChangeType(1), FileModified)
 	require.Equal(t, FileChangeType(2), FileDeleted)
 }
+
+func TestGetFileChanges_AzdxIgnoreFile(t *testing.T) {
+	dir := t.TempDir()
+	t.Chdir(dir)
+
+	// Create .azdxignore that excludes *.log files.
+	err := os.WriteFile(filepath.Join(dir, ".azdxignore"), []byte("*.log\n"), 0600)
+	require.NoError(t, err)
+
+	ctx, cancel := context.WithCancel(t.Context())
+	defer cancel()
+
+	watcher, err := NewWatcher(ctx)
+	require.NoError(t, err)
+
+	// Write an ignored file and a tracked file.
+	err = os.WriteFile(filepath.Join(dir, "debug.log"), []byte("log data"), 0600)
+	require.NoError(t, err)
+	err = os.WriteFile(filepath.Join(dir, "main.go"), []byte("package main"), 0600)
+	require.NoError(t, err)
+
+	// The tracked file should appear; the ignored file should not.
+	require.Eventually(t, func() bool {
+		for _, c := range watcher.GetFileChanges() {
+			if filepath.Base(c.Path) == "main.go" && c.ChangeType == FileCreated {
+				return true
+			}
+		}
+		return false
+	}, 2*time.Second, 50*time.Millisecond, "expected created file main.go")
+
+	// Verify the ignored file is not in the changes.
+	for _, c := range watcher.GetFileChanges() {
+		require.NotEqual(t, "debug.log", filepath.Base(c.Path),
+			"debug.log should be ignored by .azdxignore")
+	}
+}
+
+func TestGetFileChanges_AzdxIgnoreDirectory(t *testing.T) {
+	dir := t.TempDir()
+	t.Chdir(dir)
+
+	// Create .azdxignore that excludes the vendor/ directory.
+	err := os.WriteFile(filepath.Join(dir, ".azdxignore"), []byte("vendor/\n"), 0600)
+	require.NoError(t, err)
+
+	// Pre-create the ignored directory and a file inside it.
+	err = os.MkdirAll(filepath.Join(dir, "vendor", "pkg"), 0700)
+	require.NoError(t, err)
+
+	ctx, cancel := context.WithCancel(t.Context())
+	defer cancel()
+
+	watcher, err := NewWatcher(ctx)
+	require.NoError(t, err)
+
+	// Write a file inside the ignored directory and a tracked file.
+	err = os.WriteFile(filepath.Join(dir, "vendor", "pkg", "lib.go"), []byte("package pkg"), 0600)
+	require.NoError(t, err)
+	err = os.WriteFile(filepath.Join(dir, "app.go"), []byte("package main"), 0600)
+	require.NoError(t, err)
+
+	// The tracked file should appear.
+	require.Eventually(t, func() bool {
+		for _, c := range watcher.GetFileChanges() {
+			if filepath.Base(c.Path) == "app.go" && c.ChangeType == FileCreated {
+				return true
+			}
+		}
+		return false
+	}, 2*time.Second, 50*time.Millisecond, "expected created file app.go")
+
+	// Verify no file from vendor/ is in the changes.
+	for _, c := range watcher.GetFileChanges() {
+		require.NotContains(t, c.Path, "vendor",
+			"files inside vendor/ should be ignored by .azdxignore")
+	}
+}
+
+func TestGetFileChanges_NoAzdxIgnoreFile(t *testing.T) {
+	dir := t.TempDir()
+	t.Chdir(dir)
+
+	// No .azdxignore file — watcher should still start without errors.
+	ctx, cancel := context.WithCancel(t.Context())
+	defer cancel()
+
+	watcher, err := NewWatcher(ctx)
+	require.NoError(t, err)
+
+	// All files should be tracked when no ignore file exists.
+	err = os.WriteFile(filepath.Join(dir, "tracked.txt"), []byte("hello"), 0600)
+	require.NoError(t, err)
+
+	require.Eventually(t, func() bool {
+		for _, c := range watcher.GetFileChanges() {
+			if filepath.Base(c.Path) == "tracked.txt" && c.ChangeType == FileCreated {
+				return true
+			}
+		}
+		return false
+	}, 2*time.Second, 50*time.Millisecond, "expected created file tracked.txt")
+}
+
+func TestGetFileChanges_GitIgnoreRespected(t *testing.T) {
+	dir := t.TempDir()
+	t.Chdir(dir)
+
+	// Create .gitignore that excludes *.tmp files.
+	err := os.WriteFile(filepath.Join(dir, ".gitignore"), []byte("*.tmp\n"), 0600)
+	require.NoError(t, err)
+
+	ctx, cancel := context.WithCancel(t.Context())
+	defer cancel()
+
+	watcher, err := NewWatcher(ctx)
+	require.NoError(t, err)
+
+	// Write an ignored file and a tracked file.
+	err = os.WriteFile(filepath.Join(dir, "cache.tmp"), []byte("temp"), 0600)
+	require.NoError(t, err)
+	err = os.WriteFile(filepath.Join(dir, "main.txt"), []byte("content"), 0600)
+	require.NoError(t, err)
+
+	// The tracked file should appear.
+	require.Eventually(t, func() bool {
+		for _, c := range watcher.GetFileChanges() {
+			if filepath.Base(c.Path) == "main.txt" && c.ChangeType == FileCreated {
+				return true
+			}
+		}
+		return false
+	}, 2*time.Second, 50*time.Millisecond, "expected created file main.txt")
+
+	// Verify the ignored file is not in the changes.
+	for _, c := range watcher.GetFileChanges() {
+		require.NotEqual(t, "cache.tmp", filepath.Base(c.Path),
+			"cache.tmp should be ignored by .gitignore")
+	}
+}
+
+func TestIsIgnored_MatcherIntegration(t *testing.T) {
+	// Direct test of the ignore matcher as used by the watcher.
+	// This tests the Relative() code path (not Absolute()) and verifies
+	// that the matcher is wired correctly into the fileWatcher.
+	dir := t.TempDir()
+	t.Chdir(dir)
+
+	err := os.WriteFile(filepath.Join(dir, ".azdxignore"), []byte("dist/\n*.bak\n"), 0600)
+	require.NoError(t, err)
+
+	ctx, cancel := context.WithCancel(t.Context())
+	defer cancel()
+
+	w, err := NewWatcher(ctx)
+	require.NoError(t, err)
+
+	fw := w.(*fileWatcher)
+
+	// Verify the matcher is loaded and works with relative paths.
+	require.True(t, fw.ignoreMatcher.IsIgnored("dist", true))
+	require.True(t, fw.ignoreMatcher.IsIgnored("file.bak", false))
+	require.False(t, fw.ignoreMatcher.IsIgnored("src/main.go", false))
+}

From a02ac1692b359d9a6ca5bfd25a498bf8c2510e5e Mon Sep 17 00:00:00 2001
From: Jon Gallant <2163001+jongio@users.noreply.github.com>
Date: Mon, 13 Apr 2026 14:28:49 -0700
Subject: [PATCH 2/5] Improve test quality from test health review

- Fix backslash path test to actually exercise path normalization
- Add create-then-delete watcher test for delete-from-Created path
- Replace hand-rolled indexOf with strings.Index
- Add blank/whitespace line edge case test for ignore files

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 cli/azd/pkg/ignore/ignore_test.go       | 21 +++++++++++--
 cli/azd/pkg/watch/watch_helpers_test.go | 17 +++--------
 cli/azd/pkg/watch/watch_test.go         | 39 +++++++++++++++++++++++++
 3 files changed, 62 insertions(+), 15 deletions(-)

diff --git a/cli/azd/pkg/ignore/ignore_test.go b/cli/azd/pkg/ignore/ignore_test.go
index 0af654c629d..cadb8b55342 100644
--- a/cli/azd/pkg/ignore/ignore_test.go
+++ b/cli/azd/pkg/ignore/ignore_test.go
@@ -185,13 +185,16 @@ func TestNewMatcher_RelativePaths(t *testing.T) {
 func TestNewMatcher_BackslashPaths(t *testing.T) {
 	dir := t.TempDir()
 
-	writeFile(t, dir, AzdxIgnoreFile, "vendor/\n")
+	writeFile(t, dir, AzdxIgnoreFile, "*.log\nvendor/\n")
 
 	m, err := NewMatcher(dir)
 	require.NoError(t, err)
 
-	// Windows-style backslash paths should still match.
+	// Windows-style backslash paths should still match after ToSlash normalization.
 	require.True(t, m.IsIgnored("vendor", true))
+	require.True(t, m.IsIgnored("sub\\dir\\debug.log", false))
+	require.True(t, m.IsIgnored("deep\\nested\\path\\error.log", false))
+	require.False(t, m.IsIgnored("sub\\dir\\main.go", false))
 }
 
 func TestNewMatcher_UnreadableFile(t *testing.T) {
@@ -222,3 +225,17 @@ func writeFile(t *testing.T, dir, name, content string) {
 	err := os.WriteFile(filepath.Join(dir, name), []byte(content), 0600)
 	require.NoError(t, err)
 }
+
+func TestNewMatcher_BlankAndWhitespaceLines(t *testing.T) {
+	dir := t.TempDir()
+
+	// Ignore file with blank lines and whitespace-only lines interspersed.
+	writeFile(t, dir, AzdxIgnoreFile, "\n  \n*.log\n\n\t\ntemp/\n")
+
+	m, err := NewMatcher(dir)
+	require.NoError(t, err)
+
+	require.True(t, m.IsIgnored("error.log", false))
+	require.True(t, m.IsIgnored("temp", true))
+	require.False(t, m.IsIgnored("main.go", false))
+}
diff --git a/cli/azd/pkg/watch/watch_helpers_test.go b/cli/azd/pkg/watch/watch_helpers_test.go
index 625b4a201da..f0265efb7e2 100644
--- a/cli/azd/pkg/watch/watch_helpers_test.go
+++ b/cli/azd/pkg/watch/watch_helpers_test.go
@@ -4,6 +4,7 @@
 package watch
 
 import (
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -170,22 +171,12 @@ func TestFileChanges_String_PreservesOrder(t *testing.T) {
 	}
 	s := fc.String()
 
-	firstIdx := indexOf(s, "first.txt")
-	secondIdx := indexOf(s, "second.txt")
-	thirdIdx := indexOf(s, "third.txt")
+	firstIdx := strings.Index(s, "first.txt")
+	secondIdx := strings.Index(s, "second.txt")
+	thirdIdx := strings.Index(s, "third.txt")
 
 	require.Greater(t, secondIdx, firstIdx,
 		"second should appear after first")
 	require.Greater(t, thirdIdx, secondIdx,
 		"third should appear after second")
 }
-
-// indexOf returns the position of substr in s, or -1.
-func indexOf(s, substr string) int {
-	for i := 0; i+len(substr) <= len(s); i++ {
-		if s[i:i+len(substr)] == substr {
-			return i
-		}
-	}
-	return -1
-}
diff --git a/cli/azd/pkg/watch/watch_test.go b/cli/azd/pkg/watch/watch_test.go
index 91e7aa2267a..5a5bb213125 100644
--- a/cli/azd/pkg/watch/watch_test.go
+++ b/cli/azd/pkg/watch/watch_test.go
@@ -274,3 +274,42 @@ func TestIsIgnored_MatcherIntegration(t *testing.T) {
 	require.True(t, fw.ignoreMatcher.IsIgnored("file.bak", false))
 	require.False(t, fw.ignoreMatcher.IsIgnored("src/main.go", false))
 }
+
+func TestGetFileChanges_CreateThenDelete(t *testing.T) {
+	dir := t.TempDir()
+	t.Chdir(dir)
+
+	ctx, cancel := context.WithCancel(t.Context())
+	defer cancel()
+
+	watcher, err := NewWatcher(ctx)
+	require.NoError(t, err)
+
+	// Create a file and wait for it to appear in changes.
+	testFile := filepath.Join(dir, "ephemeral.txt")
+	err = os.WriteFile(testFile, []byte("short-lived"), 0600)
+	require.NoError(t, err)
+
+	require.Eventually(t, func() bool {
+		for _, c := range watcher.GetFileChanges() {
+			if filepath.Base(c.Path) == "ephemeral.txt" && c.ChangeType == FileCreated {
+				return true
+			}
+		}
+		return false
+	}, 2*time.Second, 50*time.Millisecond, "expected created file ephemeral.txt")
+
+	// Delete the file — it should be removed from Created, not added to Deleted.
+	err = os.Remove(testFile)
+	require.NoError(t, err)
+
+	require.Eventually(t, func() bool {
+		for _, c := range watcher.GetFileChanges() {
+			if filepath.Base(c.Path) == "ephemeral.txt" {
+				return false // still present — wait
+			}
+		}
+		return true // gone from all change maps
+	}, 2*time.Second, 50*time.Millisecond,
+		"ephemeral.txt should be removed from Created after delete, not moved to Deleted")
+}

From cbad496fb5aa029cb8cc32c08e579f866e1371f4 Mon Sep 17 00:00:00 2001
From: Jon Gallant <2163001+jongio@users.noreply.github.com>
Date: Mon, 13 Apr 2026 15:10:21 -0700
Subject: [PATCH 3/5] Address Copilot review feedback on test assertions

- Combine GetFileChanges assertions into single Eventually poll to avoid drain bug
- Use filepath.Rel for vendor path check instead of fragile substring match
- Use comma-ok type assertion to avoid panics in tests

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 cli/azd/pkg/watch/watch_test.go | 45 +++++++++++++++++----------------
 1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/cli/azd/pkg/watch/watch_test.go b/cli/azd/pkg/watch/watch_test.go
index 5a5bb213125..a4d03c6fa7a 100644
--- a/cli/azd/pkg/watch/watch_test.go
+++ b/cli/azd/pkg/watch/watch_test.go
@@ -7,6 +7,7 @@ import (
 	"context"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 	"time"
 
@@ -133,19 +134,18 @@ func TestGetFileChanges_AzdxIgnoreFile(t *testing.T) {
 
 	// The tracked file should appear; the ignored file should not.
 	require.Eventually(t, func() bool {
-		for _, c := range watcher.GetFileChanges() {
+		changes := watcher.GetFileChanges()
+		foundMain := false
+		for _, c := range changes {
+			if filepath.Base(c.Path) == "debug.log" {
+				return false // ignored file appeared — fail fast
+			}
 			if filepath.Base(c.Path) == "main.go" && c.ChangeType == FileCreated {
-				return true
+				foundMain = true
 			}
 		}
-		return false
-	}, 2*time.Second, 50*time.Millisecond, "expected created file main.go")
-
-	// Verify the ignored file is not in the changes.
-	for _, c := range watcher.GetFileChanges() {
-		require.NotEqual(t, "debug.log", filepath.Base(c.Path),
-			"debug.log should be ignored by .azdxignore")
-	}
+		return foundMain
+	}, 2*time.Second, 50*time.Millisecond, "expected main.go created without debug.log")
 }
 
 func TestGetFileChanges_AzdxIgnoreDirectory(t *testing.T) {
@@ -172,21 +172,21 @@ func TestGetFileChanges_AzdxIgnoreDirectory(t *testing.T) {
 	err = os.WriteFile(filepath.Join(dir, "app.go"), []byte("package main"), 0600)
 	require.NoError(t, err)
 
-	// The tracked file should appear.
+	// The tracked file should appear; vendor/ files should not.
 	require.Eventually(t, func() bool {
-		for _, c := range watcher.GetFileChanges() {
+		changes := watcher.GetFileChanges()
+		foundApp := false
+		for _, c := range changes {
+			rel, err := filepath.Rel(dir, c.Path)
+			if err == nil && (rel == "vendor" || strings.HasPrefix(filepath.ToSlash(rel), "vendor/")) {
+				return false // vendor file appeared — fail fast
+			}
 			if filepath.Base(c.Path) == "app.go" && c.ChangeType == FileCreated {
-				return true
+				foundApp = true
 			}
 		}
-		return false
-	}, 2*time.Second, 50*time.Millisecond, "expected created file app.go")
-
-	// Verify no file from vendor/ is in the changes.
-	for _, c := range watcher.GetFileChanges() {
-		require.NotContains(t, c.Path, "vendor",
-			"files inside vendor/ should be ignored by .azdxignore")
-	}
+		return foundApp
+	}, 2*time.Second, 50*time.Millisecond, "expected app.go created without vendor/ files")
 }
 
 func TestGetFileChanges_NoAzdxIgnoreFile(t *testing.T) {
@@ -267,7 +267,8 @@ func TestIsIgnored_MatcherIntegration(t *testing.T) {
 	w, err := NewWatcher(ctx)
 	require.NoError(t, err)
 
-	fw := w.(*fileWatcher)
+	fw, ok := w.(*fileWatcher)
+	require.True(t, ok, "expected NewWatcher to return *fileWatcher")
 
 	// Verify the matcher is loaded and works with relative paths.
 	require.True(t, fw.ignoreMatcher.IsIgnored("dist", true))

From 73e9e2cd0199841ac7a5f9ed077a799950a04052 Mon Sep 17 00:00:00 2001
From: Jon Gallant <2163001+jongio@users.noreply.github.com>
Date: Mon, 13 Apr 2026 16:25:00 -0700
Subject: [PATCH 4/5] Address wbreza review: doc clarity, debug logging, rename
 test

- Clarify additive/union semantics in NewMatcher doc comments
- Add debug logging for filepath.Rel() errors in both watchers
- Document cwd capture as immutable root in extension watcher
- Add TestGetFileChanges_RenameFile for rename edge case coverage

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 .../internal/cmd/watch.go                     | 11 ++++-
 cli/azd/pkg/ignore/ignore.go                  |  9 +++--
 cli/azd/pkg/watch/watch.go                    |  8 +++-
 cli/azd/pkg/watch/watch_test.go               | 40 +++++++++++++++++++
 4 files changed, 61 insertions(+), 7 deletions(-)

diff --git a/cli/azd/extensions/microsoft.azd.extensions/internal/cmd/watch.go b/cli/azd/extensions/microsoft.azd.extensions/internal/cmd/watch.go
index 2ec8b250658..366ee52d42e 100644
--- a/cli/azd/extensions/microsoft.azd.extensions/internal/cmd/watch.go
+++ b/cli/azd/extensions/microsoft.azd.extensions/internal/cmd/watch.go
@@ -7,6 +7,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"log"
 	"os"
 	"path/filepath"
 	"time"
@@ -72,6 +73,8 @@ func runWatchAction(ctx context.Context, flags *watchFlags) error {
 	}
 	defer watcher.Close()
 
+	// cwd is captured once and used as the immutable root for the entire watch session.
+	// All filepath.Rel calls reference this value so the root cannot drift.
 	cwd, err := os.Getwd()
 	if err != nil {
 		return fmt.Errorf("failed to get current working directory: %w", err)
@@ -144,7 +147,9 @@ func runWatchAction(ctx context.Context, flags *watchFlags) error {
 			info, statErr := os.Stat(event.Name)
 			isDir := statErr == nil && info.IsDir()
 
-			if relPath, relErr := filepath.Rel(cwd, event.Name); relErr == nil {
+			if relPath, relErr := filepath.Rel(cwd, event.Name); relErr != nil {
+				log.Printf("debug: failed to compute relative path for %s: %v", event.Name, relErr)
+			} else {
 				if ignoreMatcher.IsIgnored(relPath, isDir) {
 					continue
 				}
@@ -201,7 +206,9 @@ func watchRecursive(
 			}
 
 			// Check user-defined ignore patterns (.azdxignore / .gitignore).
-			if relPath, relErr := filepath.Rel(root, path); relErr == nil && relPath != "." {
+			if relPath, relErr := filepath.Rel(root, path); relErr != nil {
+				log.Printf("debug: failed to compute relative path for %s: %v", path, relErr)
+			} else if relPath != "." {
 				if ignoreMatcher.IsIgnored(relPath, true) {
 					return filepath.SkipDir
 				}
diff --git a/cli/azd/pkg/ignore/ignore.go b/cli/azd/pkg/ignore/ignore.go
index a947cc94e64..4ed3d804f59 100644
--- a/cli/azd/pkg/ignore/ignore.go
+++ b/cli/azd/pkg/ignore/ignore.go
@@ -30,7 +30,9 @@ type Matcher struct {
 }
 
 // NewMatcher creates a Matcher that loads ignore patterns from the given root directory.
-// It attempts to load both .azdxignore and .gitignore — patterns from both files are additive.
+// It loads both .azdxignore and .gitignore. Patterns are evaluated additively — a path is
+// ignored if it matches ANY pattern in EITHER file. This means .gitignore negation patterns (!)
+// cannot un-ignore paths that are matched by .azdxignore, since each file is parsed independently.
 // Missing files are silently skipped (no error). A non-nil Matcher is always returned
 // even when no ignore files exist (it simply matches nothing).
 func NewMatcher(root string) (*Matcher, error) {
@@ -41,8 +43,9 @@ func NewMatcher(root string) (*Matcher, error) {
 
 	m := &Matcher{root: absRoot}
 
-	// Load .azdxignore first (project-specific rules take precedence in ordering,
-	// though any match from either file results in ignore).
+	// Load .azdxignore first — any match from either file causes the path to be
+	// ignored (union semantics). Negation patterns in one file do not override
+	// matches in the other, because each file is parsed independently.
 	if ig, loadErr := loadIgnoreFile(absRoot, AzdxIgnoreFile); loadErr != nil {
 		return nil, loadErr
 	} else if ig != nil {
diff --git a/cli/azd/pkg/watch/watch.go b/cli/azd/pkg/watch/watch.go
index 2dabe2ff648..cdd3339f9f6 100644
--- a/cli/azd/pkg/watch/watch.go
+++ b/cli/azd/pkg/watch/watch.go
@@ -115,7 +115,9 @@ func NewWatcher(ctx context.Context) (Watcher, error) {
 				isDir := statErr == nil && info.IsDir()
 
 				// Check user-defined ignore patterns (.azdxignore / .gitignore).
-				if relPath, relErr := filepath.Rel(fw.root, name); relErr == nil {
+				if relPath, relErr := filepath.Rel(fw.root, name); relErr != nil {
+					log.Printf("debug: failed to compute relative path for %s: %v", name, relErr)
+				} else {
 					if fw.ignoreMatcher.IsIgnored(relPath, isDir) {
 						continue
 					}
@@ -186,7 +188,9 @@ func (fw *fileWatcher) watchRecursive(root string, watcher *fsnotify.Watcher) er
 			}
 
 			// Check user-defined ignore patterns (.azdxignore / .gitignore).
-			if relPath, relErr := filepath.Rel(fw.root, path); relErr == nil && relPath != "." {
+			if relPath, relErr := filepath.Rel(fw.root, path); relErr != nil {
+				log.Printf("debug: failed to compute relative path for %s: %v", path, relErr)
+			} else if relPath != "." {
 				if fw.ignoreMatcher.IsIgnored(relPath, true) {
 					return filepath.SkipDir
 				}
diff --git a/cli/azd/pkg/watch/watch_test.go b/cli/azd/pkg/watch/watch_test.go
index a4d03c6fa7a..6b2f4153504 100644
--- a/cli/azd/pkg/watch/watch_test.go
+++ b/cli/azd/pkg/watch/watch_test.go
@@ -314,3 +314,43 @@ func TestGetFileChanges_CreateThenDelete(t *testing.T) {
 	}, 2*time.Second, 50*time.Millisecond,
 		"ephemeral.txt should be removed from Created after delete, not moved to Deleted")
 }
+
+func TestGetFileChanges_RenameFile(t *testing.T) {
+	dir := t.TempDir()
+	t.Chdir(dir)
+
+	ctx, cancel := context.WithCancel(t.Context())
+	defer cancel()
+
+	watcher, err := NewWatcher(ctx)
+	require.NoError(t, err)
+
+	oldFile := filepath.Join(dir, "old.txt")
+	err = os.WriteFile(oldFile, []byte("content"), 0600)
+	require.NoError(t, err)
+
+	// Wait for the initial create event.
+	require.Eventually(t, func() bool {
+		for _, c := range watcher.GetFileChanges() {
+			if filepath.Base(c.Path) == "old.txt" {
+				return true
+			}
+		}
+		return false
+	}, 2*time.Second, 50*time.Millisecond, "expected old.txt to appear")
+
+	// Rename the file.
+	newFile := filepath.Join(dir, "new.txt")
+	err = os.Rename(oldFile, newFile)
+	require.NoError(t, err)
+
+	// The new name should appear in changes eventually.
+	require.Eventually(t, func() bool {
+		for _, c := range watcher.GetFileChanges() {
+			if filepath.Base(c.Path) == "new.txt" {
+				return true
+			}
+		}
+		return false
+	}, 2*time.Second, 50*time.Millisecond, "expected new.txt after rename")
+}

From d49fa9ef9b3e42efa2fa3acc87859beb768e24c1 Mon Sep 17 00:00:00 2001
From: Jon Gallant <2163001+jongio@users.noreply.github.com>
Date: Tue, 14 Apr 2026 16:08:30 -0700
Subject: [PATCH 5/5] address review: cross-file negation test, stat fallback
 test, error wrap, docs

- Add TestNewMatcher_CrossFileNegationCannotOverride to codify that
  .gitignore negation cannot un-ignore .azdxignore matches (W1/New 2)
- Add TestGetFileChanges_DeleteIgnoredDirFallback to test the os.Stat
  failure re-check with isDir=true for dir-only patterns (W4/New 3)
- Wrap filepath.Abs() error with context in NewMatcher (New 4)
- Add Long description to watch cobra command documenting .azdxignore
  usage with example (New 1)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 .../internal/cmd/watch.go                     | 13 +++++
 cli/azd/pkg/ignore/ignore.go                  |  3 +-
 cli/azd/pkg/ignore/ignore_test.go             | 23 +++++++++
 cli/azd/pkg/watch/watch_test.go               | 50 +++++++++++++++++++
 4 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/cli/azd/extensions/microsoft.azd.extensions/internal/cmd/watch.go b/cli/azd/extensions/microsoft.azd.extensions/internal/cmd/watch.go
index 366ee52d42e..2ae1bc173df 100644
--- a/cli/azd/extensions/microsoft.azd.extensions/internal/cmd/watch.go
+++ b/cli/azd/extensions/microsoft.azd.extensions/internal/cmd/watch.go
@@ -30,6 +30,19 @@ func newWatchCommand() *cobra.Command {
 	watchCmd := &cobra.Command{
 		Use:   "watch",
 		Short: "Watches the azd extension project for file changes and rebuilds it.",
+		Long: `Watches the azd extension project for file changes and rebuilds it.
+
+Place a .azdxignore file in your project root to exclude paths from triggering
+rebuilds. It uses standard gitignore syntax (https://git-scm.com/docs/gitignore).
+Patterns from .gitignore are also respected. Both files are additive — a path is
+ignored if it matches either file.
+
+Example .azdxignore:
+  dist/
+  build/
+  *.tmp
+  coverage/
+  !.vscode/launch.json`,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			internal.WriteCommandHeader(
 				"Watch and azd extension (azd x watch)",
diff --git a/cli/azd/pkg/ignore/ignore.go b/cli/azd/pkg/ignore/ignore.go
index 4ed3d804f59..9fde6cfe612 100644
--- a/cli/azd/pkg/ignore/ignore.go
+++ b/cli/azd/pkg/ignore/ignore.go
@@ -6,6 +6,7 @@ package ignore
 import (
 	"bytes"
 	"errors"
+	"fmt"
 	"io/fs"
 	"os"
 	"path/filepath"
@@ -38,7 +39,7 @@ type Matcher struct {
 func NewMatcher(root string) (*Matcher, error) {
 	absRoot, err := filepath.Abs(root)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("resolving root path: %w", err)
 	}
 
 	m := &Matcher{root: absRoot}
diff --git a/cli/azd/pkg/ignore/ignore_test.go b/cli/azd/pkg/ignore/ignore_test.go
index cadb8b55342..074ef7e0589 100644
--- a/cli/azd/pkg/ignore/ignore_test.go
+++ b/cli/azd/pkg/ignore/ignore_test.go
@@ -239,3 +239,26 @@ func TestNewMatcher_BlankAndWhitespaceLines(t *testing.T) {
 	require.True(t, m.IsIgnored("temp", true))
 	require.False(t, m.IsIgnored("main.go", false))
 }
+
+func TestNewMatcher_CrossFileNegationCannotOverride(t *testing.T) {
+	dir := t.TempDir()
+
+	// .azdxignore ignores all .log files.
+	writeFile(t, dir, AzdxIgnoreFile, "*.log\n")
+	// .gitignore tries to un-ignore important.log via negation.
+	writeFile(t, dir, GitIgnoreFile, "!important.log\n")
+
+	m, err := NewMatcher(dir)
+	require.NoError(t, err)
+
+	// important.log is STILL ignored — .gitignore negation cannot override
+	// .azdxignore matches because each file is parsed independently (union semantics).
+	require.True(t, m.IsIgnored("important.log", false),
+		".gitignore negation must not un-ignore paths matched by .azdxignore")
+
+	// Regular .log files are also ignored.
+	require.True(t, m.IsIgnored("debug.log", false))
+
+	// Non-log files are unaffected.
+	require.False(t, m.IsIgnored("main.go", false))
+}
diff --git a/cli/azd/pkg/watch/watch_test.go b/cli/azd/pkg/watch/watch_test.go
index 6b2f4153504..b41c493b8ac 100644
--- a/cli/azd/pkg/watch/watch_test.go
+++ b/cli/azd/pkg/watch/watch_test.go
@@ -354,3 +354,53 @@ func TestGetFileChanges_RenameFile(t *testing.T) {
 		return false
 	}, 2*time.Second, 50*time.Millisecond, "expected new.txt after rename")
 }
+
+func TestGetFileChanges_DeleteIgnoredDirFallback(t *testing.T) {
+	// Tests the os.Stat failure fallback: when a directory matching a dir-only
+	// ignore pattern (trailing /) is deleted, os.Stat fails and isDir defaults
+	// to false. The watcher re-checks with isDir=true so that the Remove event
+	// is still filtered by the directory-only pattern.
+	dir := t.TempDir()
+	t.Chdir(dir)
+
+	// .azdxignore uses a dir-only pattern (trailing slash).
+	err := os.WriteFile(filepath.Join(dir, ".azdxignore"), []byte("tmpout/\n"), 0600)
+	require.NoError(t, err)
+
+	// Pre-create the directory so watchRecursive skips it (ignored).
+	err = os.MkdirAll(filepath.Join(dir, "tmpout"), 0700)
+	require.NoError(t, err)
+
+	ctx, cancel := context.WithCancel(t.Context())
+	defer cancel()
+
+	watcher, err := NewWatcher(ctx)
+	require.NoError(t, err)
+
+	// Delete the ignored directory — the parent watcher fires a Remove event.
+	// os.Stat will fail (path gone), so isDir defaults to false.
+	// Without the fallback re-check (isDir=true), this would leak through
+	// as a file deletion since "tmpout/" only matches directories.
+	err = os.RemoveAll(filepath.Join(dir, "tmpout"))
+	require.NoError(t, err)
+
+	// Write a tracked file as a positive signal.
+	err = os.WriteFile(filepath.Join(dir, "tracked.go"), []byte("package main"), 0600)
+	require.NoError(t, err)
+
+	// Verify tracked file appears and no tmpout path leaks through.
+	require.Eventually(t, func() bool {
+		changes := watcher.GetFileChanges()
+		foundTracked := false
+		for _, c := range changes {
+			if filepath.Base(c.Path) == "tmpout" {
+				return false // ignored dir leaked through — fail fast
+			}
+			if filepath.Base(c.Path) == "tracked.go" && c.ChangeType == FileCreated {
+				foundTracked = true
+			}
+		}
+		return foundTracked
+	}, 2*time.Second, 50*time.Millisecond,
+		"expected tracked.go created without tmpout directory delete leaking through")
+}