refactor(yarn2): Introduce a class for the locator

Change the logic which extracts the module name, so that it splits up
the given string into a module name and a remainder. This prepares for
an upcoming change.

Signed-off-by: Frank Viernau <[email protected]>

Author: fviernau

plugins/package-managers/node/src/main/kotlin/yarn2/Yarn2DependencyHandler.kt

@@ -83,13 +83,11 @@ internal class Yarn2DependencyHandler(
 
 internal val PackageInfo.isProject: Boolean get() = value.substringAfterLast("@").startsWith("workspace:")
 
-internal val PackageInfo.moduleName: String get() {
+internal val PackageInfo.moduleName: String get() =
     // TODO: Handle patched packages different than non-patched ones.
     // Patch packages have locators as e.g. the following, where the first component ends with "@patch".
     // resolve@patch:resolve@npm%3A1.22.8#optional!builtin<compat/resolve>::version=1.22.8&hash=c3c19d
-    val endIndex = value.indexOf("@", startIndex = 1)
-    return value.take(endIndex)
-}
+    Locator.parse(value).moduleName
 
 internal val PackageInfo.moduleId: String get() = buildString {
     append(moduleName)
@@ -99,3 +97,18 @@ internal val PackageInfo.moduleId: String get() = buildString {
         append(children.version)
     }
 }
+
+internal data class Locator(
+    val moduleName: String,
+    val remainder: String
+) {
+    companion object {
+        fun parse(value: String): Locator {
+            val moduleNameEndIndex = value.indexOf("@", startIndex = 1)
+            return Locator(
+                moduleName = value.take(moduleNameEndIndex),
+                remainder = value.substring(moduleNameEndIndex + 1)
+            )
+        }
+    }
+}

plugins/package-managers/node/src/test/kotlin/yarn2/Yarn2DependencyHandlerTest.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2025 The ORT Project Authors (see <https://github.com/oss-review-toolkit/ort/blob/main/NOTICE>)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ * License-Filename: LICENSE
+ */
+
+package org.ossreviewtoolkit.plugins.packagemanagers.node.yarn2
+
+import io.kotest.core.spec.style.WordSpec
+import io.kotest.matchers.shouldBe
+
+class Yarn2DependencyHandlerTest : WordSpec({
+    "Locator.parse()" should {
+        "work for patched packages" {
+            val locator = Locator.parse(
+                "resolve@patch:resolve@npm%3A1.22.8#optional!builtin<compat/resolve>::version=1.22.8&hash=c3c19d"
+            )
+
+            locator.moduleName shouldBe "resolve"
+            locator.remainder shouldBe
+                "patch:resolve@npm%3A1.22.8#optional!builtin<compat/resolve>::version=1.22.8&hash=c3c19d"
+        }
+
+        "work for a package with a scope" {
+            val locator = Locator.parse("@failing/package-with-lightningcss@workspace:packages/spark")
+
+            locator.moduleName shouldBe "@failing/package-with-lightningcss"
+            locator.remainder shouldBe "workspace:packages/spark"
+        }
+    }
+})