perf: add fast path for simple recursive globs (#2884)

internal/fingerprint/glob.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/go-task/task/v3/internal/execext"
 	"github.com/go-task/task/v3/internal/filepathext"
+	"github.com/go-task/task/v3/internal/fsext"
 	"github.com/go-task/task/v3/taskfile/ast"
 )
 
@@ -32,6 +33,10 @@ func Globs(dir string, globs []*ast.Glob, useGitignore bool) ([]string, error) {
 func glob(dir string, g string) ([]string, error) {
 	g = filepathext.SmartJoin(dir, g)
 
+	if results, ok, err := fsext.FastRecursiveGlob(g); ok {
+		return results, err
+	}
+
 	fs, err := execext.ExpandFields(g)
 	if err != nil {
 		return nil, err

internal/fsext/glob.go

@@ -0,0 +1,79 @@
+package fsext
+
+import (
+	"io/fs"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+
+	"github.com/go-task/task/v3/errors"
+)
+
+var errFastGlobFallback = errors.New("fast glob fallback")
+
+// FastRecursiveGlob expands simple literal-root recursive patterns. The
+// boolean reports whether the pattern was handled or requires the full shell
+// glob expander.
+func FastRecursiveGlob(pattern string) ([]string, bool, error) {
+	pattern = filepath.Clean(pattern)
+	separator := string(os.PathSeparator)
+	marker := separator + "**" + separator
+
+	idx := strings.Index(pattern, marker)
+	if idx == -1 || strings.Contains(pattern[idx+len(marker):], marker) {
+		return nil, false, nil
+	}
+
+	root := pattern[:idx]
+	namePattern := pattern[idx+len(marker):]
+	if root == "" || namePattern == "" || strings.Contains(namePattern, separator) {
+		return nil, false, nil
+	}
+	if strings.Contains(root, "**") || strings.ContainsAny(root, "*?[]{}") {
+		return nil, false, nil
+	}
+	if strings.ContainsAny(namePattern, "{}") {
+		return nil, false, nil
+	}
+
+	var results []string
+	err := filepath.WalkDir(root, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if d.IsDir() {
+			return nil
+		}
+		if path == root {
+			return errFastGlobFallback
+		}
+
+		if d.Type()&fs.ModeSymlink != 0 {
+			info, err := os.Stat(path)
+			if err != nil {
+				return err
+			}
+			if info.IsDir() {
+				return errFastGlobFallback
+			}
+		}
+
+		matched, err := filepath.Match(namePattern, d.Name())
+		if err != nil {
+			return err
+		}
+		if matched {
+			results = append(results, filepath.ToSlash(path))
+		}
+		return nil
+	})
+	if errors.Is(err, errFastGlobFallback) {
+		return nil, false, nil
+	}
+	if err != nil {
+		return nil, true, err
+	}
+	sort.Strings(results)
+	return results, true, nil
+}

internal/fsext/glob_test.go

@@ -0,0 +1,92 @@
+package fsext
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestFastRecursiveGlob(t *testing.T) {
+	t.Parallel()
+
+	root := filepath.Join(t.TempDir(), "root")
+	require.NoError(t, os.MkdirAll(filepath.Join(root, "nested", "deeper"), 0o755))
+
+	files := []string{
+		filepath.Join(root, "direct.yaml"),
+		filepath.Join(root, "nested", "alpha.yaml"),
+		filepath.Join(root, "nested", "deeper", "beta.yaml"),
+		filepath.Join(root, "nested", "ignored.txt"),
+	}
+	for _, file := range files {
+		require.NoError(t, os.WriteFile(file, nil, 0o600))
+	}
+
+	got, ok, err := FastRecursiveGlob(filepath.Join(root, "**", "*.yaml"))
+	require.NoError(t, err)
+	require.True(t, ok)
+	require.Equal(t, []string{
+		filepath.ToSlash(files[0]),
+		filepath.ToSlash(files[1]),
+		filepath.ToSlash(files[2]),
+	}, got)
+}
+
+func TestFastRecursiveGlobFallback(t *testing.T) {
+	t.Parallel()
+
+	root := filepath.Join(t.TempDir(), "root")
+	tests := []struct {
+		name    string
+		pattern string
+	}{
+		{name: "no recursive marker", pattern: filepath.Join(root, "*.yaml")},
+		{name: "wildcard root", pattern: filepath.Join(root, "*", "**", "*.yaml")},
+		{name: "nested suffix", pattern: filepath.Join(root, "**", "generated", "*.yaml")},
+		{name: "brace suffix", pattern: filepath.Join(root, "**", "*.{yaml,yml}")},
+		{name: "multiple recursive markers", pattern: filepath.Join(root, "**", "nested", "**", "*.yaml")},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			got, ok, err := FastRecursiveGlob(tt.pattern)
+			require.NoError(t, err)
+			require.False(t, ok)
+			require.Nil(t, got)
+		})
+	}
+}
+
+func TestFastRecursiveGlobNonDirectoryRoot(t *testing.T) {
+	t.Parallel()
+
+	root := filepath.Join(t.TempDir(), "root.yaml")
+	require.NoError(t, os.WriteFile(root, nil, 0o600))
+
+	got, ok, err := FastRecursiveGlob(filepath.Join(root, "**", "*.yaml"))
+	require.NoError(t, err)
+	require.False(t, ok)
+	require.Nil(t, got)
+}
+
+func TestFastRecursiveGlobSymlinkDirectoryFallback(t *testing.T) {
+	t.Parallel()
+
+	tempDir := t.TempDir()
+	root := filepath.Join(tempDir, "root")
+	target := filepath.Join(tempDir, "target")
+	require.NoError(t, os.MkdirAll(root, 0o755))
+	require.NoError(t, os.MkdirAll(target, 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(target, "file.yaml"), nil, 0o600))
+	if err := os.Symlink(target, filepath.Join(root, "linked")); err != nil {
+		t.Skipf("cannot create directory symlink: %v", err)
+	}
+
+	got, ok, err := FastRecursiveGlob(filepath.Join(root, "**", "*.yaml"))
+	require.NoError(t, err)
+	require.False(t, ok)
+	require.Nil(t, got)
+}