Check parameter Modifiers (#678)

* Check parameter modifiers for non final modifiers

Signed-off-by: shaishavgandhi05 <shaishgandhi@gmail.com>

* Add extra line

Signed-off-by: shaishavgandhi05 <shaishgandhi@gmail.com>

* Fix formatting

Signed-off-by: shaishavgandhi05 <shaishgandhi@gmail.com>

2 files changed, 20 insertions, 1 deletions

diff --git a/src/main/java/com/squareup/javapoet/ParameterSpec.java b/src/main/java/com/squareup/javapoet/ParameterSpec.java
index 63da3f2..e30cb0f 100644
--- a/src/main/java/com/squareup/javapoet/ParameterSpec.java
+++ b/src/main/java/com/squareup/javapoet/ParameterSpec.java
@@ -160,6 +160,9 @@ public final class ParameterSpec {
     public Builder addModifiers(Iterable<Modifier> modifiers) {
       checkNotNull(modifiers, "modifiers == null");
       for (Modifier modifier : modifiers) {
+        if (!modifier.equals(Modifier.FINAL)) {
+          throw new IllegalStateException("unexpected parameter modifier: " + modifier);
+        }
         this.modifiers.add(modifier);
       }
       return this;
diff --git a/src/test/java/com/squareup/javapoet/ParameterSpecTest.java b/src/test/java/com/squareup/javapoet/ParameterSpecTest.java
index 7ae4502..f66850b 100644
--- a/src/test/java/com/squareup/javapoet/ParameterSpecTest.java
+++ b/src/test/java/com/squareup/javapoet/ParameterSpecTest.java
@@ -15,6 +15,8 @@
  */
 package com.squareup.javapoet;
 
+import java.util.ArrayList;
+import java.util.List;
 import org.junit.Test;
 
 import static com.google.common.truth.Truth.assertThat;
@@ -45,4 +47,18 @@ public class ParameterSpecTest {
           .isEqualTo("annotationSpecs == null");
     }
   }
-}
\ No newline at end of file
+
+  @Test public void addNonFinalModifier() {
+    List<Modifier> modifiers = new ArrayList<>();
+    modifiers.add(Modifier.FINAL);
+    modifiers.add(Modifier.PUBLIC);
+
+    try {
+      ParameterSpec.builder(int.class, "foo").addModifiers(modifiers);
+      fail();
+    } catch (Exception e) {
+      assertThat(e.getMessage())
+          .isEqualTo("unexpected parameter modifier: public");
+    }
+  }
+}