From: Ian Lance Taylor <iant@golang.org>
Date: Tue, 4 Oct 2022 03:08:11 +0000 (-0700)
Subject: os: if dirFS.Open fails, undo use of backslashes in error message
X-Git-Tag: go1.20rc1~722
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=755a2927d8f5bb79952db8fd17bbdec1aed91518;p=gostls13.git

os: if dirFS.Open fails, undo use of backslashes in error message

This fixes a bug introduced by CL 426094 that caused the
golang.org/x/website/internal/web tests to fail.

Fixes #56034

Change-Id: Ic64967c6d440ad260b7283a18972b20023320ab6
Reviewed-on: https://go-review.googlesource.com/c/go/+/437976
Auto-Submit: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
---

diff --git a/src/os/file.go b/src/os/file.go
index 78677c2f8f..e8d2de1b3c 100644
--- a/src/os/file.go
+++ b/src/os/file.go
@@ -644,6 +644,13 @@ func (dir dirFS) Open(name string) (fs.File, error) {
 	}
 	f, err := Open(dir.join(name))
 	if err != nil {
+		if runtime.GOOS == "windows" {
+			// Undo the backslash conversion done by dir.join.
+			perr := err.(*PathError)
+			if containsAny(perr.Path, `\`) {
+				perr.Path = string(dir) + "/" + name
+			}
+		}
 		return nil, err // nil fs.File
 	}
 	return f, nil
diff --git a/src/os/os_test.go b/src/os/os_test.go
index 4c64afaef0..ff74598362 100644
--- a/src/os/os_test.go
+++ b/src/os/os_test.go
@@ -2712,13 +2712,25 @@ func TestDirFS(t *testing.T) {
 			t.Fatal(err)
 		}
 	}
-	if err := fstest.TestFS(DirFS("./testdata/dirfs"), "a", "b", "dir/x"); err != nil {
+	fs := DirFS("./testdata/dirfs")
+	if err := fstest.TestFS(fs, "a", "b", "dir/x"); err != nil {
 		t.Fatal(err)
 	}
 
+	// Test that the error message does not contain a backslash.
+	const nonesuch = "dir/nonesuch"
+	_, err := fs.Open(nonesuch)
+	if err == nil {
+		t.Error("fs.Open of nonexistent file succeeded")
+	} else {
+		if !strings.Contains(err.Error(), nonesuch) {
+			t.Errorf("error %q does not contain %q", err, nonesuch)
+		}
+	}
+
 	// Test that Open does not accept backslash as separator.
 	d := DirFS(".")
-	_, err := d.Open(`testdata\dirfs`)
+	_, err = d.Open(`testdata\dirfs`)
 	if err == nil {
 		t.Fatalf(`Open testdata\dirfs succeeded`)
 	}