Address review: check aastore bounds before the store type check

JVMS orders aastore checks as NullPointer, then ArrayIndexOutOfBounds,
then ArrayStore. The component-type check now runs after an explicit
upper-bound check, so an out-of-bounds store of an incompatible value
throws ArrayIndexOutOfBoundsException rather than ArrayStoreException.

Author: dlunch

jvm_rust/src/interpreter.rs

@@ -106,6 +106,12 @@ impl Interpreter {
                     return Err(jvm.exception("java/lang/NullPointerException", "Array is null").await);
                 }
 
+                // JVMS: aastore reports an out-of-bounds index before any ArrayStoreException type check
+                let length = jvm.array_length(array.as_ref().unwrap()).await?;
+                if index as usize >= length {
+                    return Err(jvm.exception("java/lang/ArrayIndexOutOfBoundsException", &format!("{}", index)).await);
+                }
+
                 let element_type = jvm.array_element_type(array.as_ref().unwrap()).await?;
 
                 // operand stack has only integer, so convert it to the correct type

test_data/ArrayStore.class

@@ -3,3 +3,4 @@ ase
 object-array-ok
 nested-ok
 ase2
+aioobe

test_data/ArrayStore.txt

@@ -15,7 +15,6 @@ public static void main(String[] args) {
         o[1] = "any";
         System.out.println("object-array-ok");
 
-        // nested: String[][] holding String[] is fine, holding Integer[] is not
         Object[] m = new String[1][];
         m[0] = new String[3];
         System.out.println("nested-ok");
@@ -25,5 +24,16 @@ public static void main(String[] args) {
         } catch (ArrayStoreException e) {
             System.out.println("ase2");
         }
+
+        // out-of-bounds AND incompatible: bounds check must win
+        Object[] z = new String[0];
+        try {
+            z[1] = Integer.valueOf(1);
+            System.out.println("no-ex");
+        } catch (ArrayIndexOutOfBoundsException e) {
+            System.out.println("aioobe");
+        } catch (ArrayStoreException e) {
+            System.out.println("ase-wrong");
+        }
     }
 }