Switch back to original xmlquery package

[chocolatkey]

We go back to using the original xmlquery package now that the underlying xpath package supports easily using namespaces during querying

[Copilot]

Pull request overview

This PR migrates the EPUB parser stack back to the upstream github.com/antchfx/xmlquery (and antchfx/xpath) now that namespace-aware XPath compilation is available, removing the previously used fork and prefix-injection approach.

Changes:

• Replace github.com/readium/xmlquery usage with upstream github.com/antchfx/xmlquery and namespace-aware, precompiled XPath expressions.
• Simplify XML loading by removing the prefixes parameter from fetcher.ReadResourceAsXML and updating all call sites.
• Update EPUB parsing modules (package doc, NCX, navdoc, SMIL, encryption, metadata) and related tests to use xmlquery.QuerySelector* with compiled XPath.

Reviewed changes

Copilot reviewed 17 out of 18 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
pkg/parser/epub/utils.go	Introduces shared namespace map + XPath compilation helper; updates container.xml parsing call site.
pkg/parser/epub/parser.go	Updates XML loading calls to new ReadResourceAsXML signature.
pkg/parser/epub/parser_smil.go	Switches SMIL parsing to compiled namespace-aware XPath selectors.
pkg/parser/epub/parser_smil_test.go	Updates test XML loading to new ReadResourceAsXML signature.
pkg/parser/epub/parser_packagedoc.go	Switches OPF package document parsing to compiled namespace-aware XPath selectors.
pkg/parser/epub/parser_packagedoc_test.go	Updates test XML loading to new ReadResourceAsXML signature.
pkg/parser/epub/parser_ncx.go	Switches NCX parsing to compiled namespace-aware XPath selectors.
pkg/parser/epub/parser_ncx_test.go	Updates test XML loading to new ReadResourceAsXML signature.
pkg/parser/epub/parser_navdoc.go	Switches navdoc parsing to compiled namespace-aware XPath selectors.
pkg/parser/epub/parser_navdoc_test.go	Updates test XML loading to new ReadResourceAsXML signature.
pkg/parser/epub/parser_encryption.go	Switches encryption.xml parsing to compiled namespace-aware XPath selectors.
pkg/parser/epub/parser_encryption_test.go	Updates test XML loading to new ReadResourceAsXML signature.
pkg/parser/epub/metadata.go	Switches metadata lookup to compiled namespace-aware XPath selectors; minor slice type update.
pkg/parser/epub/metadata_test.go	Updates test XML loading to new ReadResourceAsXML signature.
pkg/parser/epub/media_overlay_service.go	Updates XML loading to new ReadResourceAsXML signature.
pkg/fetcher/resource.go	Changes ReadResourceAsXML signature and parsing implementation to upstream xmlquery.
go.mod	Adds direct requirements for antchfx/xmlquery and antchfx/xpath; removes readium/xmlquery.
go.sum	Updates checksums for dependency changes.

Comments suppressed due to low confidence (2)

pkg/parser/epub/utils.go:50

• container.xml uses a default namespace (NamespaceOPC). The unprefixed XPath /container/rootfiles/rootfile will not match namespaced elements in standard XPath, so n may be nil for valid EPUBs. Consider adding the container namespace to xmlNS and querying with a prefixed XPath (or using local-name() selectors).

	xml, err := ftchr.ReadResourceAsXML(ctx, res)
	if err != nil {
		return nil, errors.Wrap(err, "failed loading container.xml")
	}
	n := xml.SelectElement("/container/rootfiles/rootfile")
	if n == nil {
		return nil, errors.New("rootfile not found in container")

pkg/fetcher/resource.go:105

• ReadResourceAsXML converts []byte to string and then back to an io.Reader, which adds an extra allocation/copy for every XML parse. Prefer using a byte reader (e.g., bytes.NewReader(bytes)) to avoid the conversion overhead.

func ReadResourceAsXML(ctx context.Context, r Resource) (*xmlquery.Node, *ResourceError) {
	bytes, ex := r.Read(ctx, 0, 0)
	if ex != nil {
		return nil, ex
	}
	node, err := xmlquery.ParseWithOptions(strings.NewReader(string(bytes)), xmlquery.ParserOptions{
		Decoder: &xmlquery.DecoderOptions{
			Strict: true,
			Entity: xml.HTMLEntity,
		},
	})

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.