Windows: File Attributes / Resource Values crashes on files > 2GB

[gregcotten]

Stubbing this for now, but will try to make an easy repro project soon.

Windows Swift 6.1.2 release, x64

As described in title, using FileManager or URL to get or set "resource values" like modification date, creation date, file size, or even "is directory" on a file larger than 2GB will cause a crash. Anything 2GB or less works without issue.

Here's an example where I simply want to enumerate a directory, pre-caching the property "isDirectory"

enumerator(at: directoryURL, includingPropertiesForKeys: [.isDirectoryKey], options: [])

If a file in that directory is > 2GB, instant crash with:

0x0000009e1511b3, Main.dll!
0x00000073753dc6, ntdll.dll!RtlWow64GetCurrentCpuArea
0x00000073754326, ntdll.dll!RtlWow64GetCurrentCpuArea
0x0000007384692e, ntdll.dll!KiUserExceptionDispatcher
0x00000086e38f64, Foundation.dll!type metadata accessor for (extension in Foundation):FoundationEssentials.FileManager.DirectoryEnumerator
0x00000086e33f36, Foundation.dll!(extension in Foundation):FoundationEssentials.FileManager.getRelationship(_: Swift.UnsafeMutablePointer<FoundationEssentials.FileManager.URLRelationship>, of: FoundationEssentials.FileManager.SearchPathDirectory, in: FoundationEssentials.FileManager.SearchPathDomainMask, toItemAt: FoundationEssentials.URL) throws -> ()
0x00000086f354ed, Foundation.dll!Foundation.NSURL.resolvingSymlinksInPath.getter : Swift.Optional<FoundationEssentials.URL>
0x00000086f36e80, Foundation.dll!type metadata accessor for Foundation.NSURL
0x00000086f327b2, Foundation.dll!Foundation.NSURL.__allocating_init() -> Foundation.NSURL
0x00000086f31e27, Foundation.dll!Foundation.NSURL.resourceValues(forKeys: Swift.Array<Foundation.URLResourceKey>) throws -> Swift.Dictionary<Foundation.URLResourceKey, Any>
0x00000086fa5108, Foundation.dll!(extension in Foundation):FoundationEssentials.URL.resourceValues(forKeys: Swift.Set<Foundation.URLResourceKey>) throws -> Foundation.URLResourceValues
0x0000009e2838f6, Main.dll!(extension in Foundation):FoundationEssentials.URL.resourceValues(forKeys: Swift.Set<Foundation.URLResourceKey>) throws -> Foundation.URLResourceValues
0x0000009e28365c, Main.dll!(extension in Foundation):FoundationEssentials.URL.resourceValues(forKeys: Swift.Set<Foundation.URLResourceKey>) throws -> Foundation.URLResourceValues
0x0000009e283335, Main.dll!(extension in Foundation):FoundationEssentials.URL.resourceValues(forKeys: Swift.Set<Foundation.URLResourceKey>) throws -> Foundation.URLResourceValues

[jmschonfeld]

@gregcotten If you have complete sample code that reproduces the issue (along with the version of Swift that you're using) that would be helpful so we can step in and investigate. I wrote up a test case that attempts to reproduce this:

func test_urlrvCrash() throws {
    let tmp = URL.temporaryDirectory.appendingPathComponent("abc")
    try FileManager.default.createDirectory(at: tmp, withIntermediateDirectories: true)
    let data = Data(count: 1024 * 1024 * 1024 * 2 + 10) // 2GB
    let file = tmp.appendingPathComponent("test.txt")
    try data.write(to: file)
    defer { try? FileManager.default.removeItem(at: tmp) }
    print("Wrote data to \(file)")
    guard let e = FileManager.default.enumerator(at: tmp, includingPropertiesForKeys: [.isDirectoryKey], options: []) else {
        XCTFail("Failed to create enumerator")
        return
    }
    print("Made enumerator")
    while let obj = e.nextObject() {
        print("Enumerating: \(obj)")
        guard let url = obj as? URL else {
            print("Not URL")
            continue
        }
        print("Size: \(try FileManager.default.attributesOfItem(atPath: url.path)[.size])")
    }
}

But unfortunately running on arm64 Windows using the ToT version of this repo built against the latest main snapshot it doesn't crash:

Test Suite 'Selected tests' started at 2025-08-14 16:53:54.453
Test Suite 'TestURL' started at 2025-08-14 16:53:54.459
Test Case 'TestURL.test_urlrvCrash' started at 2025-08-14 16:53:54.459
Wrote data to file:///C:/Users/JMSCHO~1/AppData/Local/Temp/abc/test.txt
Made enumerator
Enumerating: file:///C:/Users/JMSCHO~1/AppData/Local/Temp/abc/test.txt
Size: Optional(2147483658)
Test Case 'TestURL.test_urlrvCrash' passed (1.614 seconds)
Test Suite 'TestURL' passed at 2025-08-14 16:53:56.073
         Executed 1 test, with 0 failures (0 unexpected) in 1.614 (1.614) seconds
Test Suite 'Selected tests' passed at 2025-08-14 16:53:56.073
         Executed 1 test, with 0 failures (0 unexpected) in 1.614 (1.614) seconds