fix: apply review feedback and clean up implementation

Author: ih0r-d

graalpy-maven-plugin/src/main/java/org/graalvm/python/maven/plugin/AbstractGraalPyMojo.java

@@ -216,7 +216,7 @@ protected void preExec(boolean enableWarnings) throws MojoExecutionException {
 		}
 	}
 
-    protected Path resolveReqFile() {
+    protected Path resolveReqFile() throws MojoExecutionException {
         if (requirementsFile == null || requirementsFile.isBlank()) {
             return null;
         }
@@ -226,16 +226,14 @@ protected Path resolveReqFile() {
                 ? path
                 : project.getBasedir().toPath().resolve(path).normalize();
 
-        if (Files.exists(finalPath)) {
-            return finalPath;
+        if (!Files.exists(finalPath)) {
+            throw new MojoExecutionException(
+                    "The configured requirementsFile does not exist: " + finalPath
+                            + "\nPlease provide a valid path to a pip-compatible requirements file."
+            );
         }
 
-        Path defaultReq = project.getBasedir().toPath().resolve("requirements.txt").normalize();
-        if (Files.exists(defaultReq)) {
-            return defaultReq;
-        }
-
-        return null;
+        return finalPath;
     }
 
     protected void postExec() throws MojoExecutionException {

graalpy-maven-plugin/src/main/java/org/graalvm/python/maven/plugin/LockPackagesMojo.java

@@ -139,7 +139,10 @@ private void checkEmptyPackages() throws MojoExecutionException {
         Path reqFilePath = resolveReqFile();
         boolean emptyPackages = packages == null || packages.isEmpty();
         boolean requirementsExists = reqFilePath != null;
-        if (emptyPackages && !requirementsExists) {
+        // Disallow lock-packages when no packages OR when requirementsFile is used
+        if (emptyPackages || requirementsExists) {
+            getLog().error("");
+            getLog().error("Missing Python dependency configuration.");
             getLog().error("");
             getLog().error(MISSING_DEPENDENCY_CONFIGURATION_ERROR);
             getLog().error("");

org.graalvm.python.embedding.tools/src/main/java/org/graalvm/python/embedding/tools/vfs/VFSUtils.java

@@ -560,9 +560,11 @@ static boolean installPackagesFromReqFile(Path venvDirectory, Launcher launcher,
             log.warning("Lock file is ignored in <requirements.txt> mode.");
             log.warning("The 'lock-packages' goal should not be used together with <requirementsFile>.");
 
-            ensureVenv(venvDirectory, graalPyVersion, launcher, log);
+            VenvContents vc = ensureVenv(venvDirectory, graalPyVersion, launcher, log);
 
             runPip(venvDirectory, "install", log, "--compile", "-r", reqFile.toString());
+            List<String> reqPackages = requirementsPackages(reqFile);
+            vc.write(reqPackages);
 
             InstalledPackages installed = InstalledPackages.fromVenv(venvDirectory);
             installed.freeze(log);
@@ -578,7 +580,6 @@ static void installPackages(Path venvDirectory, List<String> packages, Path lock
         Objects.requireNonNull(packages);
         log.info("Using inline <packages> dependency mode.");
 
-        validatePackagesOrLockFile(packages, lockFilePath);
         logVenvArgs(venvDirectory, packages, lockFilePath, launcher, graalPyVersion, log);
 
         List<String> pluginPackages = trim(packages);
@@ -684,18 +685,6 @@ public static void lockPackages(Path venvDirectory, List<String> packages, Path
 		}
 	}
 
-    private static void validatePackagesOrLockFile(List<String> packages, Path lockFilePath) {
-        boolean hasPackages = packages != null && !packages.isEmpty();
-        boolean hasLockFile = lockFilePath != null;
-
-        if (hasPackages == hasLockFile) {
-            throw new IllegalArgumentException(
-                    "Invalid configuration: <packages> and lock-file cannot be used together. Provide exactly one."
-            );
-        }
-    }
-
-
     private static void logVenvArgs(Path venvDirectory, List<String> packages, Path lockFile, Launcher launcherArgs,
 			String graalPyVersion, BuildToolLog log) throws IOException {
 		if (log.isDebugEnabled()) {
@@ -1019,7 +1008,7 @@ private static void runPip(Path venvDirectory, String command, BuildToolLog log,
 			throw new IOException(String.format("failed to execute pip %s", List.of(args)), e);
 		}
 	}
-
+    @SuppressWarnings("SameParameterValue")
 	private static void runVenvBin(Path venvDirectory, String bin, BuildToolLog log, String... args)
 			throws IOException {
 		try {
@@ -1029,10 +1018,12 @@ private static void runVenvBin(Path venvDirectory, String bin, BuildToolLog log,
 		}
 	}
 
-	private static List<String> trim(List<String> l) {
+    private static List<String> trim(List<String> l) {
 		Iterator<String> it = l.iterator();
-        for (String s : l) {
-            if (s == null || s.trim().isEmpty()) {
+        // noinspection Java8CollectionRemoveIf
+        while (it.hasNext()) {
+            String p = it.next();
+            if (p == null || p.trim().isEmpty()) {
                 it.remove();
             }
         }
@@ -1050,9 +1041,10 @@ private static void info(BuildToolLog log, String txt, Object... args) {
 		}
 	}
 
-	private static void lifecycle(BuildToolLog log, Object... args) {
+    @SuppressWarnings("SameParameterValue")
+    private static void lifecycle(BuildToolLog log, String txt, Object... args) {
 		if (log.isLifecycleEnabled()) {
-			log.lifecycle(String.format("Created GraalPy lock file: %s", args));
+            log.lifecycle(String.format(txt, args));
 		}
 	}