Merge commit 'e693fb417253d14786976bd29a456961aa8b6343'

Change-Id: I65e50880732e718fa2264e47ef7cc19e37cc2f05

1 files changed, 32 insertions, 17 deletions

diff --git a/internal/lsp/fake/workdir.go b/internal/lsp/fake/workdir.go
index d836debd8..0be1d8fdf 100644
--- a/internal/lsp/fake/workdir.go
+++ b/internal/lsp/fake/workdir.go
@@ -12,8 +12,10 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"sync"
+	"time"
 
 	"golang.org/x/tools/internal/lsp/protocol"
 	"golang.org/x/tools/internal/span"
@@ -49,16 +51,6 @@ func (r RelativeTo) RelPath(fp string) string {
 	return filepath.ToSlash(fp)
 }
 
-func writeTxtar(txt string, rel RelativeTo) error {
-	files := UnpackTxt(txt)
-	for name, data := range files {
-		if err := WriteFileData(name, data, rel); err != nil {
-			return errors.Errorf("writing to workdir: %w", err)
-		}
-	}
-	return nil
-}
-
 // WriteFileData writes content to the relative path, replacing the special
 // token $SANDBOX_WORKDIR with the relative root given by rel.
 func WriteFileData(path string, content []byte, rel RelativeTo) error {
@@ -67,12 +59,25 @@ func WriteFileData(path string, content []byte, rel RelativeTo) error {
 	if err := os.MkdirAll(filepath.Dir(fp), 0755); err != nil {
 		return errors.Errorf("creating nested directory: %w", err)
 	}
-	if err := ioutil.WriteFile(fp, []byte(content), 0644); err != nil {
-		return errors.Errorf("writing %q: %w", path, err)
+	backoff := 1 * time.Millisecond
+	for {
+		err := ioutil.WriteFile(fp, []byte(content), 0644)
+		if err != nil {
+			if isWindowsErrLockViolation(err) {
+				time.Sleep(backoff)
+				backoff *= 2
+				continue
+			}
+			return errors.Errorf("writing %q: %w", path, err)
+		}
+		return nil
 	}
-	return nil
 }
 
+// isWindowsErrLockViolation reports whether err is ERROR_LOCK_VIOLATION
+// on Windows.
+var isWindowsErrLockViolation = func(err error) bool { return false }
+
 // Workdir is a temporary working directory for tests. It exposes file
 // operations in terms of relative paths, and fakes file watching by triggering
 // events on file operations.
@@ -138,11 +143,21 @@ func toURI(fp string) protocol.DocumentURI {
 
 // ReadFile reads a text file specified by a workdir-relative path.
 func (w *Workdir) ReadFile(path string) (string, error) {
-	b, err := ioutil.ReadFile(w.AbsPath(path))
-	if err != nil {
-		return "", err
+	backoff := 1 * time.Millisecond
+	for {
+		b, err := ioutil.ReadFile(w.AbsPath(path))
+		if err != nil {
+			if runtime.GOOS == "plan9" && strings.HasSuffix(err.Error(), " exclusive use file already open") {
+				// Plan 9 enforces exclusive access to locked files.
+				// Give the owner time to unlock it and retry.
+				time.Sleep(backoff)
+				backoff *= 2
+				continue
+			}
+			return "", err
+		}
+		return string(b), nil
 	}
-	return string(b), nil
 }
 
 func (w *Workdir) RegexpRange(path, re string) (Pos, Pos, error) {