Merge changes I212bb5b7,I35a2a76d

* changes:
  Mark nullability for TextView.setText(char[])
  Don't crash after unsetting char[] in TextView

core/api/current.txt

@@ -57703,7 +57703,7 @@ package android.widget {
     method public final void setSpannableFactory(android.text.Spannable.Factory);
     method public final void setText(CharSequence);
     method public void setText(CharSequence, android.widget.TextView.BufferType);
-    method public final void setText(char[], int, int);
+    method public final void setText(@NonNull char[], int, int);
     method public final void setText(@StringRes int);
     method public final void setText(@StringRes int, android.widget.TextView.BufferType);
     method public void setTextAppearance(@StyleRes int);

core/java/android/widget/TextView.java

@@ -6456,9 +6456,8 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
     public void setText(CharSequence text, BufferType type) {
         setText(text, type, true, 0);
 
-        if (mCharWrapper != null) {
-            mCharWrapper.mChars = null;
-        }
+        // drop any potential mCharWrappper leaks
+        mCharWrapper = null;
     }
 
     @UnsupportedAppUsage
@@ -6672,11 +6671,14 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
      * since the TextView has no way to know that the text
      * has changed and that it needs to invalidate and re-layout.
      *
+     * @throws NullPointerException if text is null
+     * @throws IndexOutOfBoundsException if start or start+len are not in 0 to text.length
+     *
      * @param text char array to be displayed
      * @param start start index in the char array
      * @param len length of char count after {@code start}
      */
-    public final void setText(char[] text, int start, int len) {
+    public final void setText(@NonNull char[] text, int start, int len) {
         int oldlen = 0;
 
         if (start < 0 || len < 0 || start + len > text.length) {
@@ -13942,16 +13944,17 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
     }
 
     private static class CharWrapper implements CharSequence, GetChars, GraphicsOperations {
+        @NonNull
         private char[] mChars;
         private int mStart, mLength;
 
-        public CharWrapper(char[] chars, int start, int len) {
+        CharWrapper(@NonNull char[] chars, int start, int len) {
             mChars = chars;
             mStart = start;
             mLength = len;
         }
 
-        /* package */ void set(char[] chars, int start, int len) {
+        /* package */ void set(@NonNull char[] chars, int start, int len) {
             mChars = chars;
             mStart = start;
             mLength = len;

core/tests/coretests/src/android/widget/TextViewTest.java

@@ -304,6 +304,23 @@ public class TextViewTest {
         assertFalse(mTextView.isCursorVisible());
     }
 
+    @Test(expected = NullPointerException.class)
+    @UiThreadTest
+    public void setTextCharArrayNullThrows() {
+        mTextView = new TextView(mActivity);
+        mTextView.setText((char[]) null, 0, 0);
+    }
+
+    @Test
+    @UiThreadTest
+    public void setTextCharArrayValidAfterSetTextString() {
+        mTextView = new TextView(mActivity);
+        mTextView.setText(new char[] { 'h', 'i'}, 0, 2);
+        CharSequence charWrapper = mTextView.getText();
+        mTextView.setText("null out char wrapper");
+        assertEquals("hi", charWrapper.toString());
+    }
+
     private String createLongText() {
         int size = 600 * 1000;
         final StringBuilder builder = new StringBuilder(size);