Fixed vector of unions crash in java (#5190)

* Fixed vector of unions crash in java

* Regenerated test code

* Fixed windows tests

src/idl_gen_general.cpp

@@ -95,7 +95,7 @@ const LanguageParameters &GetLangParams(IDLOptions::Language lang) {
         "",
         "import java.nio.*;\nimport java.lang.*;\nimport "
         "java.util.*;\nimport com.google.flatbuffers.*;\n",
-        "\n@SuppressWarnings(\"unused\")",
+        "\n@SuppressWarnings(\"unused\")\n",
         "\n@javax.annotation.Generated(value=\"flatc\")\n",
         {
             "/**",
@@ -1035,6 +1035,8 @@ class GeneralGenerator : public BaseGenerator {
                           ? index
                           : lang_.accessor_prefix + "__indirect(" + index + ")";
               code += ", " + lang_.accessor_prefix + "bb";
+            } else if (vectortype.base_type == BASE_TYPE_UNION) {
+              code += index + " - bb_pos";
             } else {
               code += index;
             }

tests/JavaTest.bat

@@ -17,5 +17,5 @@ rem Compile then run the Java test.
 
 set batch_file_dir=%~d0%~p0
 
-javac -g -classpath %batch_file_dir%\..\java;%batch_file_dir%;%batch_file_dir%\namespace_test JavaTest.java
+javac -g -classpath %batch_file_dir%\..\java;%batch_file_dir%;%batch_file_dir%\namespace_test;%batch_file_dir%\union_vector JavaTest.java
-java -classpath %batch_file_dir%\..\java;%batch_file_dir%;%batch_file_dir%\namespace_test JavaTest
+java -classpath %batch_file_dir%\..\java;%batch_file_dir%;%batch_file_dir%\namespace_test;%batch_file_dir%\union_vector JavaTest

tests/JavaTest.java

@@ -73,6 +73,8 @@ class JavaTest {
 
         TestSizedInputStream();
 
+        TestVectorOfUnions();
+
         System.out.println("FlatBuffers test: completed successfully");
     }
 
@@ -415,6 +417,40 @@ class JavaTest {
         TestEq(pos.x(), 1.0f);
     }
 
+    static void TestVectorOfUnions() {
+        final FlatBufferBuilder fbb = new FlatBufferBuilder();
+
+        final int swordAttackDamage = 1;
+
+        final int[] characterVector = new int[] {
+            Attacker.createAttacker(fbb, swordAttackDamage),
+        };
+
+        final byte[] characterTypeVector = new byte[]{
+            Character.MuLan,
+        };
+
+        Movie.finishMovieBuffer(
+            fbb,
+            Movie.createMovie(
+                fbb,
+                (byte)0,
+                (byte)0,
+                Movie.createCharactersTypeVector(fbb, characterTypeVector),
+                Movie.createCharactersVector(fbb, characterVector)
+            )
+        );
+
+        final Movie movie = Movie.getRootAsMovie(fbb.dataBuffer());
+
+        TestEq(movie.charactersTypeLength(), characterTypeVector.length);
+        TestEq(movie.charactersLength(), characterVector.length);
+
+        TestEq(movie.charactersType(0), characterTypeVector[0]);
+
+        TestEq(((Attacker)movie.characters(new Attacker(), 0)).swordAttackDamage(), swordAttackDamage);
+    }
+
     static <T> void TestEq(T a, T b) {
         if (!a.equals(b)) {
             System.out.println("" + a.getClass().getName() + " " + b.getClass().getName());

tests/JavaTest.sh

@@ -36,7 +36,7 @@ if ! find "${testdir}/../java" -type f -name "*.class" -delete; then
     exit 1
 fi
 
-javac -d "${targetdir}" -classpath "${testdir}/../java:${testdir}:${testdir}/namespace_test" "${testdir}/JavaTest.java"
+javac -d "${targetdir}" -classpath "${testdir}/../java:${testdir}:${testdir}/namespace_test:${testdir}/union_vector" "${testdir}/JavaTest.java"
 
 (cd "${testdir}" && java -classpath "${targetdir}" JavaTest )
 

tests/MyGame/Example/Ability.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")public final class Ability extends Struct {
+@SuppressWarnings("unused")
+public final class Ability extends Struct {
   public void __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; }
   public Ability __assign(int _i, ByteBuffer _bb) { __init(_i, _bb); return this; }
 

tests/MyGame/Example/Monster.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")/**
+@SuppressWarnings("unused")
+/**
  * an example documentation comment: monster object
  */
 public final class Monster extends Table {

tests/MyGame/Example/Referrable.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")public final class Referrable extends Table {
+@SuppressWarnings("unused")
+public final class Referrable extends Table {
   public static Referrable getRootAsReferrable(ByteBuffer _bb) { return getRootAsReferrable(_bb, new Referrable()); }
   public static Referrable getRootAsReferrable(ByteBuffer _bb, Referrable obj) { _bb.order(ByteOrder.LITTLE_ENDIAN); return (obj.__assign(_bb.getInt(_bb.position()) + _bb.position(), _bb)); }
   public void __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; }

tests/MyGame/Example/Stat.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")public final class Stat extends Table {
+@SuppressWarnings("unused")
+public final class Stat extends Table {
   public static Stat getRootAsStat(ByteBuffer _bb) { return getRootAsStat(_bb, new Stat()); }
   public static Stat getRootAsStat(ByteBuffer _bb, Stat obj) { _bb.order(ByteOrder.LITTLE_ENDIAN); return (obj.__assign(_bb.getInt(_bb.position()) + _bb.position(), _bb)); }
   public void __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; }

tests/MyGame/Example/Test.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")public final class Test extends Struct {
+@SuppressWarnings("unused")
+public final class Test extends Struct {
   public void __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; }
   public Test __assign(int _i, ByteBuffer _bb) { __init(_i, _bb); return this; }
 

tests/MyGame/Example/TestSimpleTableWithEnum.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")final class TestSimpleTableWithEnum extends Table {
+@SuppressWarnings("unused")
+final class TestSimpleTableWithEnum extends Table {
   public static TestSimpleTableWithEnum getRootAsTestSimpleTableWithEnum(ByteBuffer _bb) { return getRootAsTestSimpleTableWithEnum(_bb, new TestSimpleTableWithEnum()); }
   public static TestSimpleTableWithEnum getRootAsTestSimpleTableWithEnum(ByteBuffer _bb, TestSimpleTableWithEnum obj) { _bb.order(ByteOrder.LITTLE_ENDIAN); return (obj.__assign(_bb.getInt(_bb.position()) + _bb.position(), _bb)); }
   public void __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; }

tests/MyGame/Example/TypeAliases.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")public final class TypeAliases extends Table {
+@SuppressWarnings("unused")
+public final class TypeAliases extends Table {
   public static TypeAliases getRootAsTypeAliases(ByteBuffer _bb) { return getRootAsTypeAliases(_bb, new TypeAliases()); }
   public static TypeAliases getRootAsTypeAliases(ByteBuffer _bb, TypeAliases obj) { _bb.order(ByteOrder.LITTLE_ENDIAN); return (obj.__assign(_bb.getInt(_bb.position()) + _bb.position(), _bb)); }
   public void __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; }

tests/MyGame/Example/Vec3.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")public final class Vec3 extends Struct {
+@SuppressWarnings("unused")
+public final class Vec3 extends Struct {
   public void __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; }
   public Vec3 __assign(int _i, ByteBuffer _bb) { __init(_i, _bb); return this; }
 

tests/MyGame/Example2/Monster.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")public final class Monster extends Table {
+@SuppressWarnings("unused")
+public final class Monster extends Table {
   public static Monster getRootAsMonster(ByteBuffer _bb) { return getRootAsMonster(_bb, new Monster()); }
   public static Monster getRootAsMonster(ByteBuffer _bb, Monster obj) { _bb.order(ByteOrder.LITTLE_ENDIAN); return (obj.__assign(_bb.getInt(_bb.position()) + _bb.position(), _bb)); }
   public void __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; }

tests/MyGame/InParentNamespace.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")public final class InParentNamespace extends Table {
+@SuppressWarnings("unused")
+public final class InParentNamespace extends Table {
   public static InParentNamespace getRootAsInParentNamespace(ByteBuffer _bb) { return getRootAsInParentNamespace(_bb, new InParentNamespace()); }
   public static InParentNamespace getRootAsInParentNamespace(ByteBuffer _bb, InParentNamespace obj) { _bb.order(ByteOrder.LITTLE_ENDIAN); return (obj.__assign(_bb.getInt(_bb.position()) + _bb.position(), _bb)); }
   public void __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; }

tests/MyGame/MonsterExtra.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")public final class MonsterExtra extends Table {
+@SuppressWarnings("unused")
+public final class MonsterExtra extends Table {
   public static MonsterExtra getRootAsMonsterExtra(ByteBuffer _bb) { return getRootAsMonsterExtra(_bb, new MonsterExtra()); }
   public static MonsterExtra getRootAsMonsterExtra(ByteBuffer _bb, MonsterExtra obj) { _bb.order(ByteOrder.LITTLE_ENDIAN); return (obj.__assign(_bb.getInt(_bb.position()) + _bb.position(), _bb)); }
   public void __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; }

tests/namespace_test/NamespaceA/NamespaceB/StructInNestedNS.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")public final class StructInNestedNS extends Struct {
+@SuppressWarnings("unused")
+public final class StructInNestedNS extends Struct {
   public void __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; }
   public StructInNestedNS __assign(int _i, ByteBuffer _bb) { __init(_i, _bb); return this; }
 

tests/namespace_test/NamespaceA/NamespaceB/TableInNestedNS.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")public final class TableInNestedNS extends Table {
+@SuppressWarnings("unused")
+public final class TableInNestedNS extends Table {
   public static TableInNestedNS getRootAsTableInNestedNS(ByteBuffer _bb) { return getRootAsTableInNestedNS(_bb, new TableInNestedNS()); }
   public static TableInNestedNS getRootAsTableInNestedNS(ByteBuffer _bb, TableInNestedNS obj) { _bb.order(ByteOrder.LITTLE_ENDIAN); return (obj.__assign(_bb.getInt(_bb.position()) + _bb.position(), _bb)); }
   public void __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; }

tests/namespace_test/NamespaceA/SecondTableInA.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")public final class SecondTableInA extends Table {
+@SuppressWarnings("unused")
+public final class SecondTableInA extends Table {
   public static SecondTableInA getRootAsSecondTableInA(ByteBuffer _bb) { return getRootAsSecondTableInA(_bb, new SecondTableInA()); }
   public static SecondTableInA getRootAsSecondTableInA(ByteBuffer _bb, SecondTableInA obj) { _bb.order(ByteOrder.LITTLE_ENDIAN); return (obj.__assign(_bb.getInt(_bb.position()) + _bb.position(), _bb)); }
   public void __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; }

tests/namespace_test/NamespaceA/TableInFirstNS.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")public final class TableInFirstNS extends Table {
+@SuppressWarnings("unused")
+public final class TableInFirstNS extends Table {
   public static TableInFirstNS getRootAsTableInFirstNS(ByteBuffer _bb) { return getRootAsTableInFirstNS(_bb, new TableInFirstNS()); }
   public static TableInFirstNS getRootAsTableInFirstNS(ByteBuffer _bb, TableInFirstNS obj) { _bb.order(ByteOrder.LITTLE_ENDIAN); return (obj.__assign(_bb.getInt(_bb.position()) + _bb.position(), _bb)); }
   public void __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; }

tests/namespace_test/NamespaceC/TableInC.java

@@ -7,7 +7,8 @@ import java.lang.*;
 import java.util.*;
 import com.google.flatbuffers.*;
 
-@SuppressWarnings("unused")public final class TableInC extends Table {
+@SuppressWarnings("unused")
+public final class TableInC extends Table {
   public static TableInC getRootAsTableInC(ByteBuffer _bb) { return getRootAsTableInC(_bb, new TableInC()); }
   public static TableInC getRootAsTableInC(ByteBuffer _bb, TableInC obj) { _bb.order(ByteOrder.LITTLE_ENDIAN); return (obj.__assign(_bb.getInt(_bb.position()) + _bb.position(), _bb)); }
   public void __init(int _i, ByteBuffer _bb) { bb_pos = _i; bb = _bb; }

tests/union_vector/Movie.java

@@ -19,7 +19,7 @@ public final class Movie extends Table {
   public int charactersTypeLength() { int o = __offset(8); return o != 0 ? __vector_len(o) : 0; }
   public ByteBuffer charactersTypeAsByteBuffer() { return __vector_as_bytebuffer(8, 1); }
   public ByteBuffer charactersTypeInByteBuffer(ByteBuffer _bb) { return __vector_in_bytebuffer(_bb, 8, 1); }
-  public Table characters(Table obj, int j) { int o = __offset(10); return o != 0 ? __union(obj, __vector(o) + j * 4) : null; }
+  public Table characters(Table obj, int j) { int o = __offset(10); return o != 0 ? __union(obj, __vector(o) + j * 4 - bb_pos) : null; }
   public int charactersLength() { int o = __offset(10); return o != 0 ? __vector_len(o) : 0; }
 
   public static int createMovie(FlatBufferBuilder builder,