Introduces ScanOption.ignoreExternalJars

equalsverifier-core/src/main/java/nl/jqno/equalsverifier/ScanOption.java

@@ -17,6 +17,15 @@ public static ScanOption recursive() {
         return ScanOptions.O.RECURSIVE;
     }
 
+    /**
+     * Signals that packages from external jars, which can't be scanned, will be ignored rather than throw an exception.
+     *
+     * @return The 'ignore external jars' flag.
+     */
+    public static ScanOption ignoreExternalJars() {
+        return ScanOptions.O.IGNORE_EXTERNAL_JARS;
+    }
+
     /**
      * Finds only classes that extend or implement the given type.
      *

equalsverifier-core/src/main/java/nl/jqno/equalsverifier/ScanOptions.java

@@ -9,7 +9,7 @@ final class ScanOptions {
     private ScanOptions() {}
 
     enum O implements ScanOption {
-        RECURSIVE;
+        RECURSIVE, IGNORE_EXTERNAL_JARS;
     }
 
     static class MustExtend implements ScanOption {
@@ -45,6 +45,9 @@ public static PackageScanOptions process(ScanOption... options) {
             if (option.equals(O.RECURSIVE)) {
                 result.scanRecursively = true;
             }
+            if (option.equals(O.IGNORE_EXTERNAL_JARS)) {
+                result.ignoreExternalJars = true;
+            }
             if (option instanceof MustExtend) {
                 MustExtend me = (MustExtend) option;
                 result.mustExtend = me.type;

equalsverifier-core/src/main/java/nl/jqno/equalsverifier/internal/reflection/PackageScanOptions.java

@@ -7,6 +7,7 @@
 public class PackageScanOptions {
 
     public boolean scanRecursively = false;
+    public boolean ignoreExternalJars = false;
     public Class<?> mustExtend = null;
     public Set<Class<?>> exceptClasses = new HashSet<>();
     public Predicate<Class<?>> exclusionPredicate = c -> false;

equalsverifier-core/src/main/java/nl/jqno/equalsverifier/internal/reflection/PackageScanner.java

@@ -4,10 +4,9 @@
 
 import java.io.File;
 import java.net.URL;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
+import java.util.*;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import nl.jqno.equalsverifier.internal.exceptions.ReflectionException;
 import nl.jqno.equalsverifier.internal.util.Validations;
@@ -30,7 +29,7 @@ private PackageScanner() {}
      * @return the classes contained in the given package.
      */
     public static List<Class<?>> getClassesIn(String packageName, PackageScanOptions options) {
-        List<Class<?>> result = getDirs(packageName)
+        List<Class<?>> result = getDirs(packageName, options)
                 .stream()
                 .flatMap(d -> getClassesInDir(packageName, d, options).stream())
                 .collect(Collectors.toList());
@@ -41,24 +40,27 @@ public static List<Class<?>> getClassesIn(String packageName, PackageScanOptions
         return result;
     }
 
-    private static List<File> getDirs(String packageName) {
+    private static List<File> getDirs(String packageName, PackageScanOptions options) {
         ClassLoader cl = Thread.currentThread().getContextClassLoader();
         String path = packageName.replace('.', '/');
         return rethrow(
             () -> Collections
                     .list(cl.getResources(path))
                     .stream()
-                    .map(r -> new File(getResourcePath(r)))
+                    .flatMap(r -> getResourcePath(r, options))
                     .collect(Collectors.toList()),
             e -> "Could not scan package " + packageName);
     }
 
-    private static String getResourcePath(URL r) {
+    private static Stream<File> getResourcePath(URL r, PackageScanOptions options) {
         String result = rethrow(() -> r.toURI().getPath(), e -> "Could not resolve resource path: " + e.getMessage());
         if (result == null) {
+            if (options.ignoreExternalJars) {
+                return Stream.empty();
+            }
             throw new ReflectionException("Could not resolve third-party resource " + r);
         }
-        return result;
+        return Stream.of(new File(result));
     }
 
     private static List<Class<?>> getClassesInDir(String packageName, File dir, PackageScanOptions options) {

equalsverifier-core/src/test/java/nl/jqno/equalsverifier/integration/operational/MultipleTypeEqualsVerifierTest.java

@@ -78,6 +78,14 @@ void fail_whenVerifyingAThirdPartyPackage() {
                 .assertMessageContains("Could not resolve");
     }
 
+    @Test
+    void failDifferently_whenVerifyingAThirdPartyPackage_givenScanOptionIgnoreExternalJars() {
+        ExpectedException
+                .when(() -> EqualsVerifier.forPackage("org.junit", ScanOption.ignoreExternalJars()).verify())
+                .assertThrows(IllegalStateException.class)
+                .assertMessageContains("org.junit", "doesn't contain any (non-Test) types");
+    }
+
     @Test
     void doesNotReportNonrecursive_whenPackageContainsRecursiveAndNonrecursiveClasses() {
         ExpectedException

equalsverifier-core/src/test/java/nl/jqno/equalsverifier/internal/reflection/PackageScannerTest.java

@@ -140,6 +140,13 @@ void dependencyPackage() {
                 .hasMessageContaining("Could not resolve third-party resource");
     }
 
+    @Test
+    void dependencyPackageWithIgnore() {
+        opts.ignoreExternalJars = true;
+        List<Class<?>> classes = PackageScanner.getClassesIn("org.junit", opts);
+        assertThat(classes).isEmpty();
+    }
+
     private void sort(List<Class<?>> classes) {
         classes.sort(Comparator.comparing(Class::getName));
     }