From 96fe3e14171dc06b609079aa6fe4fd3089a7b260 Mon Sep 17 00:00:00 2001
From: Zac Sweers <zac.sweers@gmail.com>
Date: Tue, 24 Sep 2019 18:27:36 -0400
Subject: [PATCH] Throw on missing type variables in
 Types.newParameterizedType* methods

It's a programmer error to omit this, but vararg declaration allows you to. This checks that.

We could improve it to ensure matching lengths or bounds, but this is a good start.
---
 .../src/main/java/com/squareup/moshi/Types.java  |  6 ++++++
 .../test/java/com/squareup/moshi/TypesTest.java  | 16 ++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/moshi/src/main/java/com/squareup/moshi/Types.java b/moshi/src/main/java/com/squareup/moshi/Types.java
index 1ee9fa4..a9bca93 100644
--- a/moshi/src/main/java/com/squareup/moshi/Types.java
+++ b/moshi/src/main/java/com/squareup/moshi/Types.java
@@ -109,6 +109,9 @@ public final class Types {
    * method if {@code rawType} is not enclosed in another type.
    */
   public static ParameterizedType newParameterizedType(Type rawType, Type... typeArguments) {
+    if (typeArguments.length == 0) {
+      throw new IllegalArgumentException("Missing type arguments for " + rawType);
+    }
     return new ParameterizedTypeImpl(null, rawType, typeArguments);
   }
 
@@ -118,6 +121,9 @@ public final class Types {
    */
   public static ParameterizedType newParameterizedTypeWithOwner(
       Type ownerType, Type rawType, Type... typeArguments) {
+    if (typeArguments.length == 0) {
+      throw new IllegalArgumentException("Missing type arguments for " + rawType);
+    }
     return new ParameterizedTypeImpl(ownerType, rawType, typeArguments);
   }
 
diff --git a/moshi/src/test/java/com/squareup/moshi/TypesTest.java b/moshi/src/test/java/com/squareup/moshi/TypesTest.java
index 60a005e..b2d4920 100644
--- a/moshi/src/test/java/com/squareup/moshi/TypesTest.java
+++ b/moshi/src/test/java/com/squareup/moshi/TypesTest.java
@@ -85,6 +85,22 @@ public final class TypesTest {
     assertThat(getFirstTypeArgument(type)).isEqualTo(B.class);
   }
 
+  @Test public void newParameterizedType_missingTypeVars() {
+    try {
+      Types.newParameterizedType(List.class);
+      fail("Should have errored due to missing type variable");
+    } catch (Exception e) {
+      assertThat(e).hasMessageContaining("Missing type arguments");
+    }
+
+    try {
+      Types.newParameterizedTypeWithOwner(TypesTest.class, A.class);
+      fail("Should have errored due to missing type variable");
+    } catch (Exception e) {
+      assertThat(e).hasMessageContaining("Missing type arguments");
+    }
+  }
+
   @Test public void parameterizedTypeWithRequiredOwnerMissing() throws Exception {
     try {
       Types.newParameterizedType(A.class, B.class);