(142076445) Allow URL.standardized to return an empty string URL (swiftlang#1110)

* (142076445) Allow URL.standardized to return an empty string URL

* Add ?? self to prevent force-unwrap

Author: jrflat

Sources/FoundationEssentials/URL/URL.swift

@@ -1837,7 +1837,7 @@ public struct URL: Equatable, Sendable, Hashable {
         var components = URLComponents(parseInfo: _parseInfo)
         let newPath = components.percentEncodedPath.removingDotSegments
         components.percentEncodedPath = newPath
-        return components.url(relativeTo: baseURL)!
+        return components.url(relativeTo: baseURL) ?? self
     }
 
     /// Standardizes the path of a file URL by removing dot segments.

Sources/FoundationEssentials/URL/URLComponents.swift

@@ -676,7 +676,7 @@ public struct URLComponents: Hashable, Equatable, Sendable {
             return CFURLCreateWithString(kCFAllocatorDefault, string as CFString, nil) as URL?
         }
         #endif
-        return URL(string: string)
+        return URL(string: string, relativeTo: nil)
     }
 
     /// Returns a URL created from the URLComponents relative to a base URL.

Tests/FoundationEssentialsTests/URLTests.swift

@@ -1425,6 +1425,12 @@ final class URLTests : XCTestCase {
         XCTAssertEqual(comp.path, "/my\u{0}path")
     }
 
+    func testURLStandardizedEmptyString() {
+        let url = URL(string: "../../../")!
+        let standardized = url.standardized
+        XCTAssertTrue(standardized.path().isEmpty)
+    }
+
 #if FOUNDATION_FRAMEWORK
     func testURLComponentsBridging() {
         var nsURLComponents = NSURLComponents(