encoding/xml: does not require whitespace before processing instruction value

[DemiMarie]

Go version

1.22.5 (this is from pkg.go.dev)

Output of go env in your module/workspace:

Whatever pkg.go.dev uses when this issue is filed

What did you do?

https://go.dev/play/p/rzV-FdleVIV

package main

import "encoding/xml"

func main() {
	err := xml.Unmarshal([]byte(`<?a /b?><a/>`), new(interface{}))
	if err != nil {
		panic("well-formed XML rejected")
	}
	err = xml.Unmarshal([]byte(`<?a/b?><a/>`), new(interface{}))
	if err == nil {
		panic("missing space before processing instruction value accepted")
	}
}

What did you see happen?

<?a/b?><a/> is parsed successfully.

What did you expect to see?

Error because <?a/b?> is not a well-formed processing instruction. There must be whitespace between the processing instruction target and value.

[gabyhelp]

Related Issues and Documentation

• encoding/xml: accepts XML with no space between attributes #68385
• encoding/xml: does not reject non-space before the root element or after the end of the root element #68332
• encoding/xml: Decoder does not reject xml-ProcInst preceeded by other data #65691
• encoding/xml: accepts various ill-formed XML #68293
• encoding/xml: mismatching namespace error misses a space char #49635 (closed)
• encoding/xml: add whitespace normalization from spec #20614
• encoding/xml: unmarshaller and whitespace #22146 (closed)
• encoding/xml: unexpected behavior of decoder.Skip #33222
• encoding/xml: accepts invalid XML with multiple colons #20396 (closed)
• encoding/xml: minor improvement to namespace mismatch in closing tag #48890 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[gopherbot]

Change https://go.dev/cl/609379 mentions this issue: encoding/xml: require whitespace before processing instruction value