feat: add support for exclusion patterns with '!' prefix

Add exclusion pattern support to allow users to exclude specific paths from
triggering reloads. Patterns prefixed with '!' are now parsed as exclusions and
stored separately. The globalWatcher checks if events match any exclusion
patterns before processing them, preventing excluded paths from triggering
reloads while still allowing them to be matched for filtering purposes.

- Add isExclude field to track exclusion patterns
- Parse '!' prefix during pattern initialization
- Rename allowReload to matchesEvent for clarity on matching logic
- Extract exclusion check into separate allowReload wrapper
- Add isExcludedEvent method to globalWatcher for event filtering
- Filter excluded events before debouncing in event listener

Author: jordikroon

internal/watcher/pattern.go

@@ -19,6 +19,7 @@ type pattern struct {
 	parsedValues []string
 	events       chan eventHolder
 	failureCount int
+	isExclude    bool
 
 	watcher *watcher.Watcher
 }
@@ -33,8 +34,17 @@ func (p *pattern) startSession() {
 
 // this method prepares the pattern struct (aka /path/*pattern)
 func (p *pattern) parse() (err error) {
-	// first we clean the value
-	absPattern, err := fastabs.FastAbs(p.value)
+	// detect exclusion before resolving to absolute
+	raw := strings.TrimSpace(p.value)
+	if strings.HasPrefix(raw, "!") {
+		p.isExclude = true
+		raw = strings.TrimSpace(strings.TrimPrefix(raw, "!"))
+	} else {
+		p.isExclude = false
+	}
+
+	// then we clean the value
+	absPattern, err := fastabs.FastAbs(raw)
 	if err != nil {
 		return err
 	}
@@ -81,7 +91,7 @@ func (p *pattern) parse() (err error) {
 	return nil
 }
 
-func (p *pattern) allowReload(event *watcher.Event) bool {
+func (p *pattern) matchesEvent(event *watcher.Event) bool {
 	if !isValidEventType(event.EffectType) || !isValidPathType(event) {
 		return false
 	}
@@ -92,6 +102,15 @@ func (p *pattern) allowReload(event *watcher.Event) bool {
 	return p.isValidPattern(event.PathName) || p.isValidPattern(event.AssociatedPathName)
 }
 
+func (p *pattern) allowReload(event *watcher.Event) bool {
+	// Excludes never trigger reload by themselves, but they still match events for filtering.
+	if p.isExclude {
+		return false
+	}
+
+	return p.matchesEvent(event)
+}
+
 func (p *pattern) handle(event *watcher.Event) {
 	// If the watcher prematurely sends the die@ event, retry watching
 	if event.PathType == watcher.PathTypeWatcher && strings.HasPrefix(event.PathName, "e/self/die@") && watcherIsActive.Load() {

internal/watcher/pattern_test.go

@@ -355,6 +355,44 @@ func TestAnAssociatedEventTriggersTheWatcher(t *testing.T) {
 	assert.Equal(t, e, (<-w.events).event)
 }
 
+func TestGlobalWatcherIsExcludedEvent(t *testing.T) {
+	pg := &PatternGroup{Patterns: []string{"/app/**/*.php", "!/app/vendor/**"}}
+
+	include := &pattern{patternGroup: pg, value: "/app/**/*.php"}
+	exclude := &pattern{patternGroup: pg, value: "!/app/vendor/**"}
+
+	require.NoError(t, include.parse())
+	require.NoError(t, exclude.parse())
+
+	gw := &globalWatcher{
+		groups:   []*PatternGroup{pg},
+		watchers: []*pattern{include, exclude},
+		excludes: map[*PatternGroup][]*pattern{pg: {exclude}},
+	}
+
+	inVendor := &watcher.Event{PathName: "/app/vendor/pkg/file.php"}
+	assert.True(t, include.matchesEvent(inVendor))
+	assert.True(t, gw.isExcludedEvent(pg, inVendor))
+
+	notInVendor := &watcher.Event{PathName: "/app/src/file.php"}
+	assert.True(t, include.matchesEvent(notInVendor))
+	assert.False(t, gw.isExcludedEvent(pg, notInVendor))
+}
+
+func TestExcludeMatchesAssociatedPath(t *testing.T) {
+	pg := &PatternGroup{Patterns: []string{"/app/**/*.php", "!/app/vendor/**"}}
+
+	exclude := &pattern{patternGroup: pg, value: "!/app/vendor/**"}
+	require.NoError(t, exclude.parse())
+
+	gw := &globalWatcher{
+		excludes: map[*PatternGroup][]*pattern{pg: {exclude}},
+	}
+
+	e := &watcher.Event{PathName: "/tmp/temporary", AssociatedPathName: "/app/vendor/x/file.php"}
+	assert.True(t, gw.isExcludedEvent(pg, e))
+}
+
 func relativeDir(t *testing.T, relativePath string) string {
 	t.Helper()
 

internal/watcher/watcher.go

@@ -50,6 +50,7 @@ type eventHolder struct {
 type globalWatcher struct {
 	groups   []*PatternGroup
 	watchers []*pattern
+	excludes map[*PatternGroup][]*pattern
 	events   chan eventHolder
 	stop     chan struct{}
 }
@@ -138,11 +139,18 @@ func (p *pattern) retryWatching() {
 func (g *globalWatcher) startWatching() error {
 	g.events = make(chan eventHolder)
 	g.stop = make(chan struct{})
+	g.excludes = make(map[*PatternGroup][]*pattern)
 
 	if err := g.parseFilePatterns(); err != nil {
 		return err
 	}
 
+	for _, w := range g.watchers {
+		if w.isExclude {
+			g.excludes[w.patternGroup] = append(g.excludes[w.patternGroup], w)
+		}
+	}
+
 	for _, w := range g.watchers {
 		w.events = g.events
 		w.startSession()
@@ -170,6 +178,17 @@ func (g *globalWatcher) stopWatching() {
 	}
 }
 
+func (g *globalWatcher) isExcludedEvent(pg *PatternGroup, e *watcher.Event) bool {
+	excludes := g.excludes[pg]
+	for _, ex := range excludes {
+		if ex.matchesEvent(e) {
+			return true
+		}
+	}
+
+	return false
+}
+
 func (g *globalWatcher) listenForFileEvents() {
 	timer := time.NewTimer(debounceDuration)
 	timer.Stop()
@@ -182,8 +201,11 @@ func (g *globalWatcher) listenForFileEvents() {
 		case <-g.stop:
 			return
 		case eh := <-g.events:
-			timer.Reset(debounceDuration)
+			if g.isExcludedEvent(eh.patternGroup, eh.event) {
+				continue
+			}
 
+			timer.Reset(debounceDuration)
 			eventsPerGroup[eh.patternGroup] = append(eventsPerGroup[eh.patternGroup], eh.event)
 		case <-timer.C:
 			timer.Stop()