fix(composer): Restore any modified files after analysis

plugins/package-managers/composer/src/main/kotlin/Composer.kt

@@ -51,10 +51,8 @@ import org.ossreviewtoolkit.utils.ort.showStackTrace
 
 import org.semver4j.RangesList
 import org.semver4j.RangesListFactory
-import org.semver4j.Semver
 
 private const val COMPOSER_PHAR_BINARY = "composer.phar"
-private const val COMPOSER_LOCK_FILE = "composer.lock"
 private const val SCOPE_NAME_REQUIRE = "require"
 private const val SCOPE_NAME_REQUIRE_DEV = "require-dev"
 private val ALL_SCOPE_NAMES = setOf(SCOPE_NAME_REQUIRE, SCOPE_NAME_REQUIRE_DEV)
@@ -139,7 +137,11 @@ class Composer(
         }
 
         val lockfile = stashDirectories(workingDir.resolve("vendor")).use { _ ->
-            ensureLockfile(workingDir).let {
+            val lockfileProvider = LockfileProvider(definitionFile)
+
+            requireLockfile(workingDir) { lockfileProvider.lockfile.isFile }
+
+            lockfileProvider.ensureLockfile {
                 logger.info { "Parsing lockfile at '$it'..." }
                 parseLockfile(it.readText())
             }
@@ -242,33 +244,6 @@ class Composer(
             scopeDependencies = scopes
         )
     }
-
-    private fun ensureLockfile(workingDir: File): File {
-        val lockfile = workingDir.resolve(COMPOSER_LOCK_FILE)
-
-        val hasLockfile = lockfile.isFile
-        requireLockfile(workingDir) { hasLockfile }
-        if (hasLockfile) return lockfile
-
-        // Ensure that the build is not configured to disallow the creation of lockfiles.
-        ComposerCommand.run(workingDir, "--no-interaction", "config", "--unset", "lock").requireSuccess()
-
-        val composerVersion = Semver(ComposerCommand.getVersion(workingDir))
-        val args = buildList {
-            add("--no-interaction")
-            add("update")
-            add("--ignore-platform-reqs")
-
-            if (composerVersion.major >= 2) {
-                add("--no-install")
-                add("--no-audit")
-            }
-        }
-
-        ComposerCommand.run(workingDir, *args.toTypedArray()).requireSuccess()
-
-        return lockfile
-    }
 }
 
 /**

plugins/package-managers/composer/src/main/kotlin/LockfileProvider.kt

@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2024 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.composer
+
+import java.io.File
+
+import kotlin.io.path.moveTo
+
+import org.semver4j.Semver
+
+private const val COMPOSER_LOCK_FILE = "composer.lock"
+
+class LockfileProvider(private val definitionFile: File) {
+    private val workingDir = definitionFile.parentFile
+
+    val lockfile = workingDir.resolve(COMPOSER_LOCK_FILE)
+
+    fun <T> ensureLockfile(block: (File) -> T): T {
+        if (lockfile.isFile) return block(lockfile)
+
+        val definitionFileBackup = enableLockfileCreation()
+
+        return try {
+            require(createLockFile())
+            block(lockfile)
+        } finally {
+            lockfile.delete()
+            definitionFileBackup?.also { it.toPath().moveTo(definitionFile.toPath(), overwrite = true) }
+        }
+    }
+
+    private fun enableLockfileCreation(): File? {
+        var definitionFileBackup: File? = null
+        val lockConfig = ComposerCommand.run(workingDir, "--no-interaction", "config", "lock")
+
+        if (lockConfig.isSuccess && lockConfig.stdout.trim() == "false") {
+            File.createTempFile("composer", "json", workingDir).also {
+                // The above call already creates an empty file, so the copy call needs to overwrite it.
+                definitionFileBackup = definitionFile.copyTo(it, overwrite = true)
+            }
+
+            // Ensure that the build is not configured to disallow the creation of lockfiles.
+            val unsetLock = ComposerCommand.run(workingDir, "--no-interaction", "config", "--unset", "lock")
+            if (unsetLock.isError) {
+                definitionFileBackup?.delete()
+                return null
+            }
+        }
+
+        return definitionFileBackup
+    }
+
+    private fun createLockFile(): Boolean {
+        val args = buildList {
+            add("--no-interaction")
+            add("update")
+            add("--ignore-platform-reqs")
+
+            val composerVersion = Semver(ComposerCommand.getVersion(workingDir))
+            if (composerVersion.major >= 2) {
+                add("--no-install")
+                add("--no-audit")
+            }
+        }
+
+        val update = ComposerCommand.run(workingDir, *args.toTypedArray())
+        return update.isSuccess
+    }
+}