[release-branch.go1.20] cmd/go/internal/script: retry ETXTBSY errors in scripts

Fixes #58431.
Updates #58019.

Change-Id: Ib25d668bfede6e87a3786f44bdc0db1027e3ebec
Reviewed-on: https://go-review.googlesource.com/c/go/+/463748
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
(cherry picked from commit 23c0121e4eb259cc1087d0f79a0803cbc71f500b)
Reviewed-on: https://go-review.googlesource.com/c/go/+/466856
Reviewed-by: David Chase <drchase@google.com>

diff --git a/src/cmd/go/internal/script/cmds.go b/src/cmd/go/internal/script/cmds.go
index e0eaad4c43d19c20068c89dfe5793313f2bce84b..666d2d62d30f54693f27db93e43c4cee7ec48375 100644 (file)
--- a/src/cmd/go/internal/script/cmds.go
+++ b/src/cmd/go/internal/script/cmds.go
@@ -432,21 +432,37 @@ func Exec(cancel func(*exec.Cmd) error, waitDelay time.Duration) Cmd {
 }
 
 func startCommand(s *State, name, path string, args []string, cancel func(*exec.Cmd) error, waitDelay time.Duration) (WaitFunc, error) {
-       var stdoutBuf, stderrBuf strings.Builder
-       cmd := exec.CommandContext(s.Context(), path, args...)
-       if cancel == nil {
-               cmd.Cancel = nil
-       } else {
-               cmd.Cancel = func() error { return cancel(cmd) }
-       }
-       cmd.WaitDelay = waitDelay
-       cmd.Args[0] = name
-       cmd.Dir = s.Getwd()
-       cmd.Env = s.env
-       cmd.Stdout = &stdoutBuf
-       cmd.Stderr = &stderrBuf
-       if err := cmd.Start(); err != nil {
-               return nil, err
+       var (
+               cmd                  *exec.Cmd
+               stdoutBuf, stderrBuf strings.Builder
+       )
+       for {
+               cmd = exec.CommandContext(s.Context(), path, args...)
+               if cancel == nil {
+                       cmd.Cancel = nil
+               } else {
+                       cmd.Cancel = func() error { return cancel(cmd) }
+               }
+               cmd.WaitDelay = waitDelay
+               cmd.Args[0] = name
+               cmd.Dir = s.Getwd()
+               cmd.Env = s.env
+               cmd.Stdout = &stdoutBuf
+               cmd.Stderr = &stderrBuf
+               err := cmd.Start()
+               if err == nil {
+                       break
+               }
+               if isETXTBSY(err) {
+                       // If the script (or its host process) just wrote the executable we're
+                       // trying to run, a fork+exec in another thread may be holding open the FD
+                       // that we used to write the executable (see https://go.dev/issue/22315).
+                       // Since the descriptor should have CLOEXEC set, the problem should
+                       // resolve as soon as the forked child reaches its exec call.
+                       // Keep retrying until that happens.
+               } else {
+                       return nil, err
+               }
        }
 
        wait := func(s *State) (stdout, stderr string, err error) {

diff --git a/src/cmd/go/internal/script/cmds_other.go b/src/cmd/go/internal/script/cmds_other.go
new file mode 100644 (file)
index 0000000..847b225
--- /dev/null
+++ b/src/cmd/go/internal/script/cmds_other.go
@@ -0,0 +1,11 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !(unix || windows)
+
+package script
+
+func isETXTBSY(err error) bool {
+       return false
+}

diff --git a/src/cmd/go/internal/script/cmds_posix.go b/src/cmd/go/internal/script/cmds_posix.go
new file mode 100644 (file)
index 0000000..2525f6e
--- /dev/null
+++ b/src/cmd/go/internal/script/cmds_posix.go
@@ -0,0 +1,16 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build unix || windows
+
+package script
+
+import (
+       "errors"
+       "syscall"
+)
+
+func isETXTBSY(err error) bool {
+       return errors.Is(err, syscall.ETXTBSY)
+}