net/http: using errors.Is in fs error detection

Compare error by errors.Is to detect wrapped fs errors.

Fixes #44923

Change-Id: Idf32b96a661728278b7006c3b3bcc581b8588259
GitHub-Last-Rev: dba01ddae06947fb8c6047ddfba108acd650f446
GitHub-Pull-Request: golang/go#45314
Reviewed-on: https://go-review.googlesource.com/c/go/+/306051
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
Trust: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>

diff --git a/src/net/http/fs.go b/src/net/http/fs.go
index a28ae85958fe6bff917ddfbf93fe56575601d20f..57e731e481ad49830b67a907dee59f554130579b 100644 (file)
--- a/src/net/http/fs.go
+++ b/src/net/http/fs.go
@@ -46,7 +46,7 @@ type Dir string
 // to a possibly better non-nil error. In particular, it turns OS-specific errors
 // about opening files in non-directories into fs.ErrNotExist. See Issue 18984.
 func mapDirOpenError(originalErr error, name string) error {
-       if os.IsNotExist(originalErr) || os.IsPermission(originalErr) {
+       if errors.Is(originalErr, fs.ErrNotExist) || errors.Is(originalErr, fs.ErrPermission) {
                return originalErr
        }
 
@@ -670,10 +670,10 @@ func serveFile(w ResponseWriter, r *Request, fs FileSystem, name string, redirec
 // and historically Go's ServeContent always returned just "404 Not Found" for
 // all errors. We don't want to start leaking information in error messages.
 func toHTTPError(err error) (msg string, httpStatus int) {
-       if os.IsNotExist(err) {
+       if errors.Is(err, fs.ErrNotExist) {
                return "404 page not found", StatusNotFound
        }
-       if os.IsPermission(err) {
+       if errors.Is(err, fs.ErrPermission) {
                return "403 Forbidden", StatusForbidden
        }
        // Default:

diff --git a/src/net/http/fs_test.go b/src/net/http/fs_test.go
index 1bf207e0f751bacc29984e1e7c71fa507c6ba6a5..b42ade1e8ac4f4482b37fbee242205f6384e857e 100644 (file)
--- a/src/net/http/fs_test.go
+++ b/src/net/http/fs_test.go
@@ -1265,16 +1265,18 @@ func TestFileServerNotDirError(t *testing.T) {
                        if err == nil {
                                t.Fatal("err == nil; want != nil")
                        }
-                       if !os.IsNotExist(err) {
-                               t.Errorf("err = %v; os.IsNotExist(err) = %v; want true", err, os.IsNotExist(err))
+                       if !errors.Is(err, fs.ErrNotExist) {
+                               t.Errorf("err = %v; errors.Is(err, fs.ErrNotExist) = %v; want true", err,
+                                       errors.Is(err, fs.ErrNotExist))
                        }
 
                        _, err = dir.Open("/index.html/not-a-dir/not-a-file")
                        if err == nil {
                                t.Fatal("err == nil; want != nil")
                        }
-                       if !os.IsNotExist(err) {
-                               t.Errorf("err = %v; os.IsNotExist(err) = %v; want true", err, os.IsNotExist(err))
+                       if !errors.Is(err, fs.ErrNotExist) {
+                               t.Errorf("err = %v; errors.Is(err, fs.ErrNotExist) = %v; want true", err,
+                                       errors.Is(err, fs.ErrNotExist))
                        }
                })
        }