From b9436ed439a011f51dbf4f1c798f2ad70b663242 Mon Sep 17 00:00:00 2001
From: Marcono1234 <Marcono1234@users.noreply.github.com>
Date: Wed, 16 Feb 2022 00:58:27 +0100
Subject: [PATCH] Remove TypeToken check for type variable

As mentioned in review comments, there are cases during serialization where
usage of the type variable is not so problematic (but still not ideal).
---
 .../com/google/gson/reflect/TypeToken.java    | 27 +--------
 .../google/gson/reflect/TypeTokenTest.java    | 56 -------------------
 2 files changed, 1 insertion(+), 82 deletions(-)

diff --git a/gson/src/main/java/com/google/gson/reflect/TypeToken.java b/gson/src/main/java/com/google/gson/reflect/TypeToken.java
index f8e75a18ac..7a0f2eb047 100644
--- a/gson/src/main/java/com/google/gson/reflect/TypeToken.java
+++ b/gson/src/main/java/com/google/gson/reflect/TypeToken.java
@@ -22,7 +22,6 @@
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.lang.reflect.TypeVariable;
-import java.lang.reflect.WildcardType;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -89,9 +88,7 @@ private Type getTypeTokenTypeArgument() {
     if (superclass instanceof ParameterizedType) {
       ParameterizedType parameterized = (ParameterizedType) superclass;
       if (parameterized.getRawType() == TypeToken.class) {
-        Type typeArgument = $Gson$Types.canonicalize(parameterized.getActualTypeArguments()[0]);
-        verifyNoTypeVariable(typeArgument);
-        return typeArgument;
+        return $Gson$Types.canonicalize(parameterized.getActualTypeArguments()[0]);
       }
     }
     // Check for raw TypeToken as superclass
@@ -104,28 +101,6 @@ else if (superclass == TypeToken.class) {
     throw new IllegalStateException("Must only create direct subclasses of TypeToken");
   }
 
-  private static void verifyNoTypeVariable(Type type) {
-    if (type instanceof TypeVariable) {
-      TypeVariable<?> typeVariable = (TypeVariable<?>) type;
-      throw new IllegalArgumentException("TypeToken type argument must not contain a type variable; captured type variable "
-          + typeVariable.getName() + " declared by " + typeVariable.getGenericDeclaration());
-    } else if (type instanceof GenericArrayType) {
-      verifyNoTypeVariable(((GenericArrayType) type).getGenericComponentType());
-    } else if (type instanceof ParameterizedType) {
-      for (Type typeArgument : ((ParameterizedType) type).getActualTypeArguments()) {
-        verifyNoTypeVariable(typeArgument);
-      }
-    } else if (type instanceof WildcardType) {
-      WildcardType wildcardType = (WildcardType) type;
-      for (Type bound : wildcardType.getLowerBounds()) {
-        verifyNoTypeVariable(bound);
-      }
-      for (Type bound : wildcardType.getUpperBounds()) {
-        verifyNoTypeVariable(bound);
-      }
-    }
-  }
-
   /**
    * Returns the raw (non-generic) type for this type.
    */
diff --git a/gson/src/test/java/com/google/gson/reflect/TypeTokenTest.java b/gson/src/test/java/com/google/gson/reflect/TypeTokenTest.java
index 0d82d283bb..1cdd7361af 100644
--- a/gson/src/test/java/com/google/gson/reflect/TypeTokenTest.java
+++ b/gson/src/test/java/com/google/gson/reflect/TypeTokenTest.java
@@ -146,62 +146,6 @@ class SubSubTypeToken2 extends SubTypeToken<Integer> {}
     }
   }
 
-  /**
-   * TypeToken type argument must not contain a type variable because, due to
-   * type erasure, at runtime only the bound of the type variable is available
-   * which is likely not what the user wanted.
-   *
-   * <p>Note that type variables are allowed for the methods calling {@code TypeToken(Type)}
-   * because there the return type is {@code TypeToken<?>} which does not give
-   * a false sense of type-safety.
-   */
-  public <T> void testTypeTokenTypeVariable() {
-    try {
-      new TypeToken<T>() {};
-      fail();
-    } catch (IllegalArgumentException expected) {
-      assertEquals("TypeToken type argument must not contain a type variable; captured type variable T "
-          + "declared by public void com.google.gson.reflect.TypeTokenTest.testTypeTokenTypeVariable()",
-          expected.getMessage());
-    }
-
-    try {
-      new TypeToken<List<List<T>>>() {};
-      fail();
-    } catch (IllegalArgumentException expected) {
-      assertEquals("TypeToken type argument must not contain a type variable; captured type variable T "
-          + "declared by public void com.google.gson.reflect.TypeTokenTest.testTypeTokenTypeVariable()",
-          expected.getMessage());
-    }
-
-    try {
-      new TypeToken<List<? extends List<T>>>() {};
-      fail();
-    } catch (IllegalArgumentException expected) {
-      assertEquals("TypeToken type argument must not contain a type variable; captured type variable T "
-          + "declared by public void com.google.gson.reflect.TypeTokenTest.testTypeTokenTypeVariable()",
-          expected.getMessage());
-    }
-
-    try {
-      new TypeToken<List<? super List<T>>>() {};
-      fail();
-    } catch (IllegalArgumentException expected) {
-      assertEquals("TypeToken type argument must not contain a type variable; captured type variable T "
-          + "declared by public void com.google.gson.reflect.TypeTokenTest.testTypeTokenTypeVariable()",
-          expected.getMessage());
-    }
-
-    try {
-      new TypeToken<List<T>[]>() {};
-      fail();
-    } catch (IllegalArgumentException expected) {
-      assertEquals("TypeToken type argument must not contain a type variable; captured type variable T "
-          + "declared by public void com.google.gson.reflect.TypeTokenTest.testTypeTokenTypeVariable()",
-          expected.getMessage());
-    }
-  }
-
   @SuppressWarnings("rawtypes")
   public void testTypeTokenRaw() {
     try {