encoding/xml: wrap charsetReader errors

This change wraps the errors from the CharsetReader function so the caller can distinguish different error conditions.

Context: I have an XML file with an unknown encoding which I like to handle separately. I like to use the CharsetReader for this but the error type has not been forwarded.

Change-Id: I6739a0dee04ec376cd20536be2806ce7f50c5213
GitHub-Last-Rev: ada9dd510f9a5b7f8c9473f6864077e0ed6898bd
GitHub-Pull-Request: golang/go#60199
Reviewed-on: https://go-review.googlesource.com/c/go/+/494897
Reviewed-by: Heschi Kreinick <heschi@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>

diff --git a/src/encoding/xml/xml.go b/src/encoding/xml/xml.go
index 1f3084e5ca83a016d7eb8c278d9fb80e9bbc9da7..d12198694485c17cc8335af7c67f73d08097aa42 100644 (file)
--- a/src/encoding/xml/xml.go
+++ b/src/encoding/xml/xml.go
@@ -262,6 +262,9 @@ func NewTokenDecoder(t TokenReader) *Decoder {
 // or EOF before all expected end elements,
 // it will return an error.
 //
+// If CharsetReader is called and returns an error,
+// the error is wrapped and returned.
+//
 // Token implements XML name spaces as described by
 // https://www.w3.org/TR/REC-xml-names/. Each of the
 // Name structures contained in the Token has the Space
@@ -634,7 +637,7 @@ func (d *Decoder) rawToken() (Token, error) {
                                }
                                newr, err := d.CharsetReader(enc, d.r.(io.Reader))
                                if err != nil {
-                                       d.err = fmt.Errorf("xml: opening charset %q: %v", enc, err)
+                                       d.err = fmt.Errorf("xml: opening charset %q: %w", enc, err)
                                        return nil, d.err
                                }
                                if newr == nil {