Registry: don't loose query parameters on URL absolutization (#47)

* Registry: don't loose query parameters on URL absolutization

* Registry: throw a proper exception when Location header parsing fails

Sources/tart/OCI/Registry.swift

@@ -61,15 +61,11 @@ class Registry {
       throw RegistryError.MissingLocationHeader
     }
 
-    var uploadLocation = URL(string: uploadLocationRaw)!
-
-    // If the URL provided in the Location header
-    // is relative — make it absolute.
-    if uploadLocation.absoluteString == uploadLocation.relativeString {
-      uploadLocation = URL(string: uploadLocation.path, relativeTo: baseURL)!
+    guard let uploadLocation = URL(string: uploadLocationRaw) else {
+      throw RegistryError.MalformedHeader(why: "Location header contains invalid URL: \"\(uploadLocationRaw)\"")
     }
 
-    return URLComponents(url: uploadLocation, resolvingAgainstBaseURL: true)!
+    return URLComponents(url: uploadLocation.absolutize(baseURL), resolvingAgainstBaseURL: true)!
   }
 
   public func pushBlob(fromData: Data, chunkSize: Int = 5 * 1024 * 1024) async throws -> String {
@@ -137,8 +133,8 @@ class Registry {
   ) async throws -> (Data, HTTPURLResponse) {
     var urlComponents = urlComponents
 
-    if !parameters.isEmpty {
-      urlComponents.queryItems = Array()
+    if urlComponents.queryItems == nil {
+      urlComponents.queryItems = []
     }
     urlComponents.queryItems?.append(contentsOf: parameters.map { key, value -> URLQueryItem in
       URLQueryItem(name: key, value: value)

Sources/tart/OCI/URL+Absolutize.swift

@@ -0,0 +1,7 @@
+import Foundation
+
+extension URL {
+  func absolutize(_ baseURL: URL) -> Self {
+    URL(string: absoluteString, relativeTo: baseURL)!
+  }
+}

Tests/TartTests/URLAbsolutizationTests.swift

@@ -0,0 +1,18 @@
+import XCTest
+@testable import tart
+
+final class URLAbsolutizationTets: XCTestCase {
+  func testNeedsAbsolutization() throws {
+    let url = URL(string: "/v2/some/path?some=query")!
+            .absolutize(URL(string: "https://example.com/v2/")!)
+
+    XCTAssertEqual(url.absoluteString, "https://example.com/v2/some/path?some=query")
+  }
+
+  func testDoesntNeedAbsolutization() throws {
+    let url = URL(string: "https://example.org/v2/some/path?some=query")!
+            .absolutize(URL(string: "https://example.com/v2/")!)
+
+    XCTAssertEqual(url.absoluteString, "https://example.org/v2/some/path?some=query")
+  }
+}