Check that modern APIs are used

build.gradle

@@ -18,6 +18,7 @@ plugins {
     // https://github.com/diffplug/spotless/tags ; see tags starting "gradle/"
     // Only works on JDK 11+ (even including the plugin crashes Gradle on JDK 8).
     id 'com.diffplug.spotless' version '8.2.1'
+    id 'com.github.andygoossens.modernizer' version '1.12.0'
 }
 
 // There is another `repositories { ... }` block below; if you change this one, change that one as well.
@@ -174,14 +175,14 @@ allprojects { currentProj ->
     //   * backward-incompatible changes have been made to APIs or elsewhere.
     // To make a snapshot release, version should end in "-SNAPSHOT", then: ./gradlew publish
     version = '3.49.5-eisop1-SNAPSHOT'
+    group = 'io.github.eisop'
 
     apply plugin: 'java'
     apply plugin: 'eclipse'
     apply plugin: 'com.gradleup.shadow'
     apply plugin: 'de.undercouch.download'
     apply plugin: 'net.ltgt.errorprone'
-
-    group = 'io.github.eisop'
+    apply plugin: 'com.github.andygoossens.modernizer'
 
     // Keep in sync with "repositories { ... }" block above.
     repositories {
@@ -443,6 +444,12 @@ allprojects { currentProj ->
             }
         }
 
+        modernizer {
+            failOnViolations = true
+            includeTestClasses = true
+            javaVersion = 8
+        }
+
         // Add the fat checker.jar to the classpath of every Javadoc task. This allows Javadoc in
         // any module to reference classes in any other module.
         // Also, build and use ManualTaglet as a taglet.

checker-util/src/test/java/org/checkerframework/checker/optional/util/OptionalUtilTest.java

@@ -16,7 +16,7 @@ public void test_castPresent() {
 
         Assert.assertTrue(nonEmptyOpt.isPresent());
         @Present Optional<String> foo = OptionalUtil.castPresent(nonEmptyOpt);
-        Assert.assertEquals(foo.get(), "non-empty");
+        Assert.assertEquals("non-empty", foo.orElseThrow());
 
         Assert.assertFalse(emptyOpt.isPresent());
         Assert.assertThrows(Error.class, () -> OptionalUtil.castPresent(emptyOpt));

checker/bin-devel/test-misc.sh

@@ -70,3 +70,6 @@ git diff --exit-code docs/manual/contributors.tex \
 
 # Check gradle tasks are configured properly
 ./gradlew tasks
+
+# Check that modern APIs are used
+./gradlew modernizer

checker/src/main/java/org/checkerframework/checker/units/UnitsAnnotatedTypeFactory.java

@@ -43,8 +43,8 @@
 import org.checkerframework.javacutil.UserError;
 import org.plumelib.reflection.Signatures;
 
-import java.io.File;
 import java.lang.annotation.Annotation;
+import java.nio.file.Paths;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
@@ -229,7 +229,7 @@ private void loadAllExternalUnits() {
 
         // load external directories of units
         for (String directoryName : checker.getStringsOption("unitsDirs", ':')) {
-            if (!new File(directoryName).exists()) {
+            if (!Paths.get(directoryName).toFile().exists()) {
                 throw new UserError("Nonexistent directory in -AunitsDirs: " + directoryName);
             }
             loadExternalDirectory(directoryName);

dataflow/src/main/java/org/checkerframework/dataflow/cfg/visualize/CFGVisualizeOptions.java

@@ -3,6 +3,7 @@
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 import java.io.File;
+import java.nio.file.Path;
 
 /**
  * Options for running analysis on files.
@@ -90,7 +91,7 @@ public static CFGVisualizeOptions parseArgs(String[] args) {
             System.exit(1);
         }
         String input = args[0];
-        File file = new File(input);
+        File file = Path.of(input).toFile();
         if (!file.canRead()) {
             printError("Cannot read input file: " + file.getAbsolutePath());
             printUsage();

dataflow/src/main/java/org/checkerframework/dataflow/cfg/visualize/DOTCFGVisualizer.java

@@ -346,7 +346,7 @@ public void shutdown() {
         // Open for append, in case of multiple sub-checkers.
         try (Writer fstream =
                         Files.newBufferedWriter(
-                                Paths.get(outDir + "/methods.txt"),
+                                Paths.get(outDir, "methods.txt"),
                                 StandardCharsets.UTF_8,
                                 StandardOpenOption.CREATE,
                                 StandardOpenOption.APPEND);

framework-test/src/main/java/org/checkerframework/framework/test/AinferValidatePerDirectoryTest.java

@@ -172,7 +172,7 @@ public void run() {
         // Only run if annotated files have been created.
         // See ainferTest task.
         if (generationTest != null
-                && !new File("tests/ainfer-" + CHECKER_SHORT_NAME + "/annotated/").exists()) {
+                && !Files.exists(Paths.get("tests", "ainfer-" + CHECKER_SHORT_NAME, "annotated"))) {
             throw new RuntimeException(generationTest + " must be run before this test.");
         }
         super.run();

framework-test/src/main/java/org/checkerframework/framework/test/CheckerFrameworkPerDirectoryTest.java

@@ -155,7 +155,7 @@ public void run() {
                 customizeOptions(Collections.unmodifiableList(checkerOptions));
         TestConfiguration config =
                 TestConfigurationBuilder.buildDefaultConfiguration(
-                        new File(resolveTestDirectory(), testDir).getPath(),
+                        resolveTestDirectory().toPath().resolve(testDir).toString(),
                         testFiles,
                         classpathExtra,
                         checkerNames,

framework-test/src/main/java/org/checkerframework/framework/test/CheckerFrameworkPerFileTest.java

@@ -94,7 +94,7 @@ public void run() {
                 customizeOptions(Collections.unmodifiableList(checkerOptions));
         TestConfiguration config =
                 TestConfigurationBuilder.buildDefaultConfiguration(
-                        new File(resolveTestDirectory(), testDir).getPath(),
+                        resolveTestDirectory().toPath().resolve(testDir).toString(),
                         testFile,
                         checker,
                         customizedOptions,

framework-test/src/main/java/org/checkerframework/framework/test/CheckerFrameworkRootedTest.java

@@ -1,6 +1,7 @@
 package org.checkerframework.framework.test;
 
 import java.io.File;
+import java.nio.file.Paths;
 
 /** Encapsulates the directory root to search within for test files to compile. */
 abstract class CheckerFrameworkRootedTest {
@@ -17,9 +18,9 @@ public CheckerFrameworkRootedTest() {}
     protected File resolveTestDirectory() {
         TestRootDirectory annotation = getClass().getAnnotation(TestRootDirectory.class);
         if (annotation != null) {
-            return new File(annotation.value());
+            return Paths.get(annotation.value()).toFile();
         }
-        return new File("tests");
+        return Paths.get("tests").toFile();
     }
 
     /**

framework-test/src/main/java/org/checkerframework/framework/test/CheckerFrameworkWPIPerDirectoryTest.java

@@ -106,7 +106,7 @@ protected void doNotTypecheck(
      * @return whether {@code file} contains {@code skipComment}
      */
     public static boolean hasSkipComment(File file, String skipComment) {
-        try (Scanner in = new Scanner(file, StandardCharsets.UTF_8.name())) {
+        try (Scanner in = new Scanner(file, StandardCharsets.UTF_8)) {
             while (in.hasNext()) {
                 String nextLine = in.nextLine();
                 if (nextLine.contains(skipComment)) {

framework-test/src/main/java/org/checkerframework/framework/test/RootedSuite.java

@@ -5,6 +5,7 @@
 import org.junit.runners.model.InitializationError;
 
 import java.io.File;
+import java.nio.file.Path;
 import java.util.List;
 
 /**
@@ -33,8 +34,8 @@ public RootedSuite(Class<?> klass, List<Runner> runners) throws InitializationEr
     protected final File resolveTestDirectory() {
         TestRootDirectory annotation = getTestClass().getAnnotation(TestRootDirectory.class);
         if (annotation != null) {
-            return new File(annotation.value());
+            return Path.of(annotation.value()).toFile();
         }
-        return new File("tests");
+        return Path.of("tests").toFile();
     }
 }

framework-test/src/main/java/org/checkerframework/framework/test/TestConfigurationBuilder.java

@@ -8,6 +8,7 @@
 import org.plumelib.util.StringsPlume;
 
 import java.io.File;
+import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -597,10 +598,15 @@ private static <T> List<T> catListAndIterable(
      * @return the output directory
      */
     public static File getOutputDirFromProperty() {
-        return new File(
-                System.getProperty(
-                        "tests.outputDir",
-                        "tests" + File.separator + "build" + File.separator + "testclasses"));
+        return Paths.get(
+                        System.getProperty(
+                                "tests.outputDir",
+                                "tests"
+                                        + File.separator
+                                        + "build"
+                                        + File.separator
+                                        + "testclasses"))
+                .toFile();
     }
 
     /**

framework-test/src/main/java/org/checkerframework/framework/test/TestUtilities.java

@@ -85,7 +85,7 @@ public class TestUtilities {
      * @return found files
      */
     public static List<File> findNestedJavaTestFiles(String... dirNames) {
-        return findRelativeNestedJavaFiles(new File("tests"), dirNames);
+        return findRelativeNestedJavaFiles(Paths.get("tests").toFile(), dirNames);
     }
 
     /**
@@ -96,7 +96,7 @@ public static List<File> findNestedJavaTestFiles(String... dirNames) {
      * @return found files
      */
     public static List<File> findRelativeNestedJavaFiles(String parent, String... dirNames) {
-        return findRelativeNestedJavaFiles(new File(parent), dirNames);
+        return findRelativeNestedJavaFiles(Paths.get(parent).toFile(), dirNames);
     }
 
     /**
@@ -111,7 +111,7 @@ public static List<File> findRelativeNestedJavaFiles(File parent, String... dirN
 
         int i = 0;
         for (String dirName : dirNames) {
-            dirs[i] = new File(parent, dirName);
+            dirs[i] = parent.toPath().resolve(dirName).toFile();
             ++i;
         }
 
@@ -140,7 +140,7 @@ public static List<List<File>> findJavaFilesPerDirectory(File parent, String...
         List<List<File>> filesPerDirectory = new ArrayList<>();
 
         for (String dirName : dirNames) {
-            File dir = new File(parent, dirName).toPath().toAbsolutePath().normalize().toFile();
+            File dir = parent.toPath().resolve(dirName).toAbsolutePath().normalize().toFile();
             if (dir.isDirectory()) {
                 filesPerDirectory.addAll(findJavaTestFilesInDirectory(dir));
             } else {
@@ -168,8 +168,8 @@ public static List<List<File>> findJavaFilesPerDirectory(File parent, String...
                             throw new BugInCF("test directory does not exist: %s", dir);
                         }
                         p =
-                                new File(parent, allSystemPath.replace("/", File.separator))
-                                        .toPath()
+                                parent.toPath()
+                                        .resolve(allSystemPath.replace("/", File.separator))
                                         .toAbsolutePath()
                                         .normalize()
                                         .toFile();
@@ -206,7 +206,7 @@ private static List<List<File>> findJavaTestFilesInDirectory(File dir) {
         }
         Arrays.sort(dirContents);
         for (String fileName : dirContents) {
-            File file = new File(dir, fileName);
+            File file = dir.toPath().resolve(fileName).toFile();
             if (file.isDirectory()) {
                 fileGroupedByDirectory.addAll(findJavaTestFilesInDirectory(file));
             } else if (isJavaTestFile(file)) {
@@ -228,7 +228,7 @@ private static List<List<File>> findJavaTestFilesInDirectory(File dir) {
      */
     public static List<Object[]> findFilesInParent(File parent, String... fileNames) {
         return CollectionsPlume.mapList(
-                (String fileName) -> new Object[] {new File(parent, fileName)}, fileNames);
+                (String fileName) -> new Object[] {parent.toPath().resolve(fileName)}, fileNames);
     }
 
     /**
@@ -385,12 +385,13 @@ public static String summarizeSourceFiles(List<File> javaFiles) {
     }
 
     public static File getTestFile(String fileRelativeToTestsDir) {
-        return new File("tests", fileRelativeToTestsDir);
+        return Paths.get("tests", fileRelativeToTestsDir).toFile();
     }
 
     public static File findComparisonFile(File testFile) {
         File comparisonFile =
-                new File(testFile.getParent(), testFile.getName().replace(".java", ".out"));
+                Paths.get(testFile.getParent(), testFile.getName().replace(".java", ".out"))
+                        .toFile();
         return comparisonFile;
     }
 

framework-test/src/main/java/org/checkerframework/framework/test/diagnostics/JavaDiagnosticReader.java

@@ -14,6 +14,7 @@
 import java.io.LineNumberReader;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
+import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
@@ -208,7 +209,7 @@ private JavaDiagnosticReader(File toRead, StringToTestDiagnosticLine codec) {
     private JavaDiagnosticReader(
             JavaFileObject toReadFileObject, StringToTestDiagnosticLine codec) {
         this.codec = codec;
-        this.filename = new File(toReadFileObject.getName()).getName();
+        this.filename = Paths.get(toReadFileObject.getName()).toFile().getName();
         LineNumberReader reader = null;
         try {
             reader = new LineNumberReader(toReadFileObject.openReader(true));