filewatcher: only recurse when directory has a /... suffix

Previously filewatcher.Watch would recurse into all directories.

Also fix a bug where max depth of the directory walk was including the root directory path in the depth.

Adds tests for a couple functions

internal/filewatcher/watch.go

@@ -57,9 +57,28 @@ func Watch(dirs []string, run func(pkg string) error) error {
 	}
 }
 
-func findAllDirs(dirs []string, depth int) []string {
-	var output []string
+func findAllDirs(dirs []string, maxDepth int) []string {
+	if len(dirs) == 0 {
+		dirs = []string{"./..."}
+	}
+
+	var output []string // nolint: prealloc
+	for _, dir := range dirs {
+		const recur = "/..."
+		if strings.HasSuffix(dir, recur) {
+			dir = strings.TrimSuffix(dir, recur)
+			output = append(output, findSubDirs(dir, maxDepth)...)
+			continue
+		}
+		output = append(output, dir)
+	}
+	return output
+}
 
+func findSubDirs(rootDir string, maxDepth int) []string {
+	var output []string
+	// add root dir depth so that maxDepth is relative to the root dir
+	maxDepth += pathDepth(rootDir)
 	walker := func(path string, info os.FileInfo, err error) error {
 		if err != nil {
 			log.Warnf("failed to watch %v: %v", path, err)
@@ -68,32 +87,24 @@ func findAllDirs(dirs []string, depth int) []string {
 		if !info.IsDir() {
 			return nil
 		}
-		if isMaxDepth(path, depth) || exclude(path) {
+		if pathDepth(path) > maxDepth || exclude(path) {
 			log.Debugf("Ignoring %v because of max depth or exclude list", path)
 			return filepath.SkipDir
 		}
-		if noGoFiles(path) {
+		if !hasGoFiles(path) {
 			log.Debugf("Ignoring %v because it has no .go files", path)
 			return nil
 		}
 		output = append(output, path)
 		return nil
 	}
-
-	if len(dirs) == 0 {
-		dirs = []string{"."}
-	}
-
-	for _, dir := range dirs {
-		dir = strings.TrimSuffix(dir, "/...")
-		// nolint: errcheck // error is handled by walker func
-		filepath.Walk(dir, walker)
-	}
+	// nolint: errcheck // error is handled by walker func
+	filepath.Walk(rootDir, walker)
 	return output
 }
 
-func isMaxDepth(path string, depth int) bool {
-	return strings.Count(filepath.Clean(path), string(filepath.Separator)) >= depth
+func pathDepth(path string) int {
+	return strings.Count(filepath.Clean(path), string(filepath.Separator))
 }
 
 // return true if path is vendor, testdata, or starts with a dot
@@ -108,25 +119,25 @@ func exclude(path string) bool {
 	return false
 }
 
-func noGoFiles(path string) bool {
+func hasGoFiles(path string) bool {
 	fh, err := os.Open(path)
 	if err != nil {
-		return true
+		return false
 	}
 
 	for {
 		names, err := fh.Readdirnames(20)
 		switch {
 		case err == io.EOF:
-			return true
+			return false
 		case err != nil:
 			log.Warnf("failed to read directory %v: %v", path, err)
-			return true
+			return false
 		}
 
 		for _, name := range names {
 			if strings.HasSuffix(name, ".go") {
-				return false
+				return true
 			}
 		}
 	}

internal/filewatcher/watch_test.go

@@ -1,11 +1,15 @@
 package filewatcher
 
 import (
+	"fmt"
+	"path/filepath"
 	"testing"
 	"time"
 
 	"github.com/fsnotify/fsnotify"
 	"gotest.tools/v3/assert"
+	"gotest.tools/v3/env"
+	"gotest.tools/v3/fs"
 )
 
 func TestHandler_HandleEvent(t *testing.T) {
@@ -76,3 +80,80 @@ func TestHandler_HandleEvent(t *testing.T) {
 		})
 	}
 }
+
+func TestHasGoFiles(t *testing.T) {
+	t.Run("none", func(t *testing.T) {
+		tmpDir := fs.NewDir(t, t.Name(), fs.WithFile("readme.md", ""))
+		defer tmpDir.Remove()
+		assert.Assert(t, !hasGoFiles(tmpDir.Path()))
+	})
+	t.Run("empty", func(t *testing.T) {
+		tmpDir := fs.NewDir(t, t.Name())
+		defer tmpDir.Remove()
+		assert.Assert(t, !hasGoFiles(tmpDir.Path()))
+	})
+	t.Run("some go files", func(t *testing.T) {
+		tmpDir := fs.NewDir(t, t.Name(), fs.WithFile("main.go", ""))
+		defer tmpDir.Remove()
+		assert.Assert(t, hasGoFiles(tmpDir.Path()))
+	})
+	t.Run("many go files", func(t *testing.T) {
+		tmpDir := fs.NewDir(t, t.Name())
+		for i := 0; i < 47; i++ {
+			fs.Apply(t, tmpDir, fs.WithFile(fmt.Sprintf("file%d.go", i), ""))
+		}
+		defer tmpDir.Remove()
+		assert.Assert(t, hasGoFiles(tmpDir.Path()))
+	})
+}
+
+func TestFindAllDirs(t *testing.T) {
+	goFile := fs.WithFile("file.go", "")
+	dirOne := fs.NewDir(t, t.Name(),
+		goFile,
+		fs.WithFile("not-a-dir", ""),
+		fs.WithDir("no-go-files"),
+		fs.WithDir(".starts-with-dot", goFile))
+	defer dirOne.Remove()
+	var path string
+	for i := 1; i <= 10; i++ {
+		path = filepath.Join(path, fmt.Sprintf("%d", i))
+		var ops []fs.PathOp
+		if i != 4 && i != 5 {
+			ops = []fs.PathOp{goFile}
+		}
+		fs.Apply(t, dirOne, fs.WithDir(path, ops...))
+	}
+
+	dirTwo := fs.NewDir(t, t.Name(),
+		goFile,
+		// subdir should be ignored, dirTwo is used without /... suffix
+		fs.WithDir("subdir", goFile))
+	defer dirTwo.Remove()
+
+	dirs := findAllDirs([]string{dirOne.Path() + "/...", dirTwo.Path()}, maxDepth)
+	expected := []string{
+		dirOne.Path(),
+		dirOne.Join("1"),
+		dirOne.Join("1/2"),
+		dirOne.Join("1/2/3"),
+		dirOne.Join("1/2/3/4/5/6"),
+		dirOne.Join("1/2/3/4/5/6/7"),
+		dirTwo.Path(),
+	}
+	assert.DeepEqual(t, dirs, expected)
+}
+
+func TestFindAllDirs_DefaultPath(t *testing.T) {
+	goFile := fs.WithFile("file.go", "")
+	dirOne := fs.NewDir(t, t.Name(),
+		goFile,
+		fs.WithDir("a", goFile),
+		fs.WithDir("b", goFile))
+	defer dirOne.Remove()
+
+	defer env.ChangeWorkingDir(t, dirOne.Path())()
+	dirs := findAllDirs([]string{}, maxDepth)
+	expected := []string{".", "a", "b"}
+	assert.DeepEqual(t, dirs, expected)
+}