XMLParser malformed XML handling differs between macOS and Linux #5281
Description
Malformed XML (unclosed tags):
- macOS:
parse()returnsfalse,parseErrorOccurredcalled once - Linux:
parse()returnstrue,parseErrorOccurredcalled multiple times
Reproduction
macOS
import Foundation
#if canImport(FoundationXML)
import FoundationXML
#endif
class MalformedDelegate: NSObject, XMLParserDelegate {
var parseError: Error?
var elementCount = 0
func parser(_ parser: XMLParser, didStartElement elementName: String, namespaceURI: String?, qualifiedName qName: String?, attributes attributeDict: [String : String] = [:]) {
elementCount += 1
print(" Started element: \(elementName)")
}
func parser(_ parser: XMLParser, parseErrorOccurred parseError: Error) {
self.parseError = parseError
print(" Parse error detected: \(parseError.localizedDescription)")
}
}
let malformedXML = """
<?xml version="1.0" encoding="utf-8"?>
<xliff version="1.2">
<file source-language="en">
<body>
<trans-unit id="key">
<source>Value
</trans-unit>
</body>
</file>
</xliff>
"""
let delegate = MalformedDelegate()
let parser = XMLParser(data: malformedXML.data(using: .utf8)!)
parser.delegate = delegate
let success = parser.parse()
print("\nParse returned: \(success)")
print("Elements started: \(delegate.elementCount)")
print("Parse error: \(delegate.parseError?.localizedDescription ?? "none")")Linux
import Foundation
#if canImport(FoundationXML)
import FoundationXML
#endif
class MalformedDelegate: XMLParserDelegate {
var parseError: Error?
var elementCount = 0
func parser(_ parser: XMLParser, didStartElement elementName: String, namespaceURI: String?, qualifiedName qName: String?, attributes attributeDict: [String : String] = [:]) {
elementCount += 1
print(" Started element: \(elementName)")
}
func parser(_ parser: XMLParser, parseErrorOccurred parseError: Error) {
self.parseError = parseError
print(" Parse error detected: \(parseError.localizedDescription)")
}
}
let malformedXML = """
<?xml version="1.0" encoding="utf-8"?>
<xliff version="1.2">
<file source-language="en">
<body>
<trans-unit id="key">
<source>Value
</trans-unit>
</body>
</file>
</xliff>
"""
let delegate = MalformedDelegate()
let parser = XMLParser(data: malformedXML.data(using: .utf8)!)
parser.delegate = delegate
let success = parser.parse()
print("\nParse returned: \(success)")
print("Elements started: \(delegate.elementCount)")
print("Parse error: \(delegate.parseError?.localizedDescription ?? "none")")macOS Output
Started element: xliff
Started element: file
Started element: body
Started element: trans-unit
Started element: source
Parse error detected: The operation couldn't be completed. (NSXMLParserErrorDomain error 76.)
Parse returned: false
Elements started: 5
Parse error: The operation couldn't be completed. (NSXMLParserErrorDomain error 76.)
Linux Output
Started element: xliff
Started element: file
Started element: body
Started element: trans-unit
Started element: source
Parse error detected: The operation could not be completed. (NSXMLParserErrorDomain error 76.)
Parse error detected: The operation could not be completed. (NSXMLParserErrorDomain error 76.)
Parse error detected: The operation could not be completed. (NSXMLParserErrorDomain error 76.)
Parse error detected: The operation could not be completed. (NSXMLParserErrorDomain error 76.)
Parse error detected: The operation could not be completed. (NSXMLParserErrorDomain error 5.)
Parse returned: true
Elements started: 5
Parse error: The operation could not be completed. (NSXMLParserErrorDomain error 5.)
On Linux, parseErrorOccurred is called multiple times but parse() still returns true.
Environment
- Swift: 6.2 (swift-6.2-RELEASE)
- macOS: Sequoia 15.1 (Build 26.0.1)
- Linux: Ubuntu 24.04.3 LTS (Docker: swift:6.2)
Related Issues
- [SR-11192] XML Parsing Error Inconsistency #3989 - XML Parsing Error Inconsistency (malformed XML handling)
- [SR-2301] NSXMLParser not fully implemented #4342 - NSXMLParser not fully implemented