[5.3] Fix: Analysis of relative links for the Atom feed

[Grotax]

In addition to alexdebril#422
alexdebril#422 - partially corrupted the formation of Link for the Atom feed.
I learned about this only the day before yesterday and urgently made this PR.

[Copilot]

Pull Request Overview

This PR fixes how relative links are resolved in Atom feeds by preserving the original item link for analysis and applying a base URL when needed.

• Introduce linkForAnalysis in Node to keep the original link separate from the resolved link
• Update Atom Link rule to prepend the host when resolving relative href values
• Ensure the XML parser seeds new items with the original link for proper relative resolution
• Add a comprehensive suite of tests covering various relative, absolute, protocol‐relative, fragment, query, and empty‐href scenarios

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tests/FeedIo/Rule/Atom/LinkTest.php	New tests for resolving relative, absolute, protocol‐relative, fragment, query, and empty hrefs in Atom <link> elements
src/FeedIo/Rule/Atom/Link.php	Updated logic to detect relative URLs and prepend the base host
src/FeedIo/Parser/XmlParser.php	Changed parsing to use setLinkForAnalysis instead of setLink to seed original link
src/FeedIo/Feed/Node.php	Added linkForAnalysis property and accessors, updated host extraction and content rewriting to use it
CHANGELOG.md	Documented the fix under "Fixed"

Comments suppressed due to low confidence (3)

CHANGELOG.md:14

• There are stray blank list markers above and an extra + prefix—clean up the bullet formatting to be a single - Fix: Analysis of relative links for the Atom feed (#10) entry.

- Fix: Analysis of relative links for the Atom feed (#10)

src/FeedIo/Feed/Node.php:145

• The signature allows a default null but does not declare ?string $link, which can lead to type‐checking issues. Change to public function setLink(?string $link = null): NodeInterface for strict null safety.

    public function setLink(string $link = null): NodeInterface

src/FeedIo/Feed/Node.php:154

• Similarly, this method should declare its parameter as nullable (?string $link) to match the default null and avoid runtime type warnings.

    public function setLinkForAnalysis(string $link = null): NodeInterface

[Copilot]

If linkForAnalysis is null, calling explode() on it below will raise a warning. Add an explicit null check before using it, or coerce to an empty string.

Suggested change

	$itemFullLink = $this->getLinkForAnalysis();
	$itemFullLink = $this->getLinkForAnalysis();
	if (is_null($itemFullLink)) {
	$itemFullLink = ''; // Coerce to an empty string to avoid runtime errors
	}

[SMillerDev]

Some small nits