[SR-14584] XMLParserDelegate: undefined entities are not reported by default

[swift-ci]

Previous ID	SR-14584
Radar	rdar://problem/77526326
Original Reporter	Stefan Springer (JIRA User)
Type	Bug

Environment

Swift 5.4 on macOS 11.3 on Apple Silicon

Additional Detail from JIRA

Votes	0
Component/s	Foundation
Labels	Bug
Assignee	None
Priority	Medium

md5: ccf84183c6acdb626506fbfa2df23ece

Issue Description:

Undefined entities only reported to a XMLParserDelegate instance via parser(_ :resolveExternalEntityName:systemID), so when you do not use this method because you do not expect to having to resolve entities by yourself, those entities are not reported to you, and what is worse, no errors are reported. In this case content gets lost. But content should never disappear without error messages.

Possible solution: Report an error if undefined entities are not handled by parser(_ :resolveExternalEntityName:systemID).

See the small Github repository https://github.com/stefanspringer1/SwiftXMLParserExamples for reference.

Related issues:

https://bugs.swift.org/browse/SR-14581

https://bugs.swift.org/browse/SR-14582

https://bugs.swift.org/browse/SR-14583

https://bugs.swift.org/browse/SR-2301

[typesanitizer]

@swift-ci create