From 3128edfe59d3f0d677ae9ad24bf2c7474056787a Mon Sep 17 00:00:00 2001
From: Tobias Klauser <tklauser@distanz.ch>
Date: Wed, 15 Mar 2023 19:26:33 +0100
Subject: [PATCH] syscall: let EPLAN9 and EWINDOWS implement
 errors.ErrUnsupported

As suggested by Bryan. This should fix the failing
TestIPConnSpecificMethods on plan9 after CL 476217 was submitted.

For #41198

Change-Id: I18e87b3aa7c9f7d48a1bd9c2819340acd1d2ca4e
Reviewed-on: https://go-review.googlesource.com/c/go/+/476578
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
---
 src/syscall/syscall_plan9.go   | 3 +++
 src/syscall/syscall_windows.go | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/src/syscall/syscall_plan9.go b/src/syscall/syscall_plan9.go
index 92414709ef4609..759f8051e860f3 100644
--- a/src/syscall/syscall_plan9.go
+++ b/src/syscall/syscall_plan9.go
@@ -12,6 +12,7 @@
 package syscall
 
 import (
+	"errors"
 	"internal/oserror"
 	"runtime"
 	"unsafe"
@@ -43,6 +44,8 @@ func (e ErrorString) Is(target error) bool {
 	case oserror.ErrNotExist:
 		return checkErrMessageContent(e, "does not exist", "not found",
 			"has been removed", "no parent")
+	case errors.ErrUnsupported:
+		return checkErrMessageContent(e, "not supported")
 	}
 	return false
 }
diff --git a/src/syscall/syscall_windows.go b/src/syscall/syscall_windows.go
index 1d8b6568c078ff..ae9b49a28d4ac7 100644
--- a/src/syscall/syscall_windows.go
+++ b/src/syscall/syscall_windows.go
@@ -156,6 +156,8 @@ func (e Errno) Is(target error) bool {
 		return e == ERROR_FILE_NOT_FOUND ||
 			e == _ERROR_BAD_NETPATH ||
 			e == ERROR_PATH_NOT_FOUND
+	case errorspkg.ErrUnsupported:
+		return e == EWINDOWS
 	}
 	return false
 }