watch: FileEvents must always be absolute (#1841)

there were a lot of confused tests that were using relative paths, then trying to workaround this

pkg/watch/notify.go

@@ -2,6 +2,8 @@ package watch
 
 import (
 	"expvar"
+	"fmt"
+	"path/filepath"
 
 	"github.com/windmilleng/tilt/internal/logger"
 )
@@ -11,7 +13,18 @@ var (
 )
 
 type FileEvent struct {
-	Path string
+	path string
+}
+
+func NewFileEvent(p string) FileEvent {
+	if !filepath.IsAbs(p) {
+		panic(fmt.Sprintf("NewFileEvent only accepts absolute paths. Actual: %s", p))
+	}
+	return FileEvent{path: p}
+}
+
+func (e FileEvent) Path() string {
+	return e.path
 }
 
 type Notify interface {

pkg/watch/notify_test.go

@@ -600,16 +600,16 @@ F:
 			f.T().Fatal(err)
 
 		case event := <-f.notify.Events():
-			if strings.Contains(event.Path, syncPath) {
+			if strings.Contains(event.Path(), syncPath) {
 				break F
 			}
-			if strings.Contains(event.Path, anySyncPath) {
+			if strings.Contains(event.Path(), anySyncPath) {
 				continue
 			}
 
 			// Don't bother tracking duplicate changes to the same path
 			// for testing.
-			if len(f.events) > 0 && f.events[len(f.events)-1].Path == event.Path {
+			if len(f.events) > 0 && f.events[len(f.events)-1].Path() == event.Path() {
 				continue
 			}
 

pkg/watch/watcher_darwin.go

@@ -4,6 +4,8 @@ import (
 	"path/filepath"
 	"time"
 
+	"github.com/pkg/errors"
+
 	"github.com/windmilleng/tilt/internal/logger"
 	"github.com/windmilleng/tilt/internal/ospath"
 
@@ -62,9 +64,7 @@ func (d *darwinNotify) loop() {
 					continue
 				}
 
-				d.events <- FileEvent{
-					Path: e.Path,
-				}
+				d.events <- NewFileEvent(e.Path)
 			}
 		}
 	}
@@ -133,6 +133,10 @@ func newWatcher(paths []string, ignore PathMatcher, l logger.Logger) (*darwinNot
 	}
 
 	for _, path := range paths {
+		path, err := filepath.Abs(path)
+		if err != nil {
+			return nil, errors.Wrap(err, "newWatcher")
+		}
 		dw.initAdd(path)
 	}
 

pkg/watch/watcher_naive.go

@@ -207,6 +207,10 @@ func newWatcher(paths []string, ignore PathMatcher, l logger.Logger) (*naiveNoti
 	wrappedEvents := make(chan FileEvent)
 	notifyList := make(map[string]bool, len(paths))
 	for _, path := range paths {
+		path, err := filepath.Abs(path)
+		if err != nil {
+			return nil, errors.Wrap(err, "newWatcher")
+		}
 		notifyList[path] = true
 	}