feat(lock): add NKLock etag parsing

Co-authored-by: Rello <13385119+Rello@users.noreply.github.com>

Author: Copilot

Sources/NextcloudKit/Models/NKLock.swift

@@ -47,6 +47,11 @@ public struct NKLock: Equatable, Sendable {
     ///
     public let token: String?
 
+    ///
+    /// Normalized resource ETag returned by the LOCK response.
+    ///
+    public let etag: String?
+
     ///
     /// Initialize from a SwiftyXML accessor.
     ///
@@ -90,6 +95,8 @@ public struct NKLock: Equatable, Sendable {
         self.time = Date(timeIntervalSince1970: rawTime)
         self.timeOut = Date(timeIntervalSince1970: rawTime + rawTimeOut)
         self.token = lockToken
+        self.etag = properties["d:getetag"].text?
+            .trimmingCharacters(in: CharacterSet(charactersIn: "\""))
     }
 
     ///
@@ -103,13 +110,14 @@ public struct NKLock: Equatable, Sendable {
     ///
     /// Initialize from raw values.
     ///
-    public init(owner: String, ownerEditor: String, ownerType: NKLockType, ownerDisplayName: String, time: Date?, timeOut: Date?, token: String?) {
+    public init(owner: String, ownerEditor: String, ownerType: NKLockType, ownerDisplayName: String, time: Date?, timeOut: Date?, token: String?, etag: String? = nil) {
         self.owner = owner
         self.ownerEditor = ownerEditor
         self.ownerType = ownerType
         self.ownerDisplayName = ownerDisplayName
         self.time = time
         self.timeOut = timeOut
         self.token = token
+        self.etag = etag
     }
 }

Tests/NextcloudKitUnitTests/NKLockUnitTests.swift

@@ -0,0 +1,53 @@
+// SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+import Foundation
+import Testing
+@testable import NextcloudKit
+
+@Suite("NKLock parsing")
+struct NKLockUnitTests {
+    private func makeLockData(etagElement: String = "") -> Data {
+        let xml = """
+        <?xml version="1.0"?>
+        <d:prop xmlns:d="DAV:" xmlns:nc="http://nextcloud.org/ns">
+            <nc:lock>1</nc:lock>
+            <nc:lock-owner>user-id</nc:lock-owner>
+            <nc:lock-owner-editor>text</nc:lock-owner-editor>
+            <nc:lock-owner-type>\(NKLockType.token.rawValue)</nc:lock-owner-type>
+            <nc:lock-owner-displayname>User Name</nc:lock-owner-displayname>
+            <nc:lock-time>1</nc:lock-time>
+            <nc:lock-timeout>60</nc:lock-timeout>
+            <nc:lock-token>files_lock/test-token</nc:lock-token>
+            \(etagElement)
+        </d:prop>
+        """
+
+        return Data(xml.utf8)
+    }
+
+    @Test("Parses quoted ETag from LOCK response")
+    func parsesQuotedETag() {
+        let lock = NKLock(data: makeLockData(etagElement: "<d:getetag>\"etag-after-lock\"</d:getetag>"))
+
+        #expect(lock != nil)
+        #expect(lock?.token == "files_lock/test-token")
+        #expect(lock?.etag == "etag-after-lock")
+    }
+
+    @Test("Missing ETag keeps lock parsing valid")
+    func missingETagDoesNotFailParsing() {
+        let lock = NKLock(data: makeLockData())
+
+        #expect(lock != nil)
+        #expect(lock?.etag == nil)
+    }
+
+    @Test("Unquoted ETag is preserved")
+    func preservesUnquotedETag() {
+        let lock = NKLock(data: makeLockData(etagElement: "<d:getetag>etag-after-lock</d:getetag>"))
+
+        #expect(lock != nil)
+        #expect(lock?.etag == "etag-after-lock")
+    }
+}