Issue checkstyle#3238: Java 8 Grammar: annotations on arrays and varargs

src/main/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoWhitespaceAfterCheck.java

@@ -170,8 +170,7 @@ public void setAllowLineBreaks(boolean allowLineBreaks) {
     public void visitToken(DetailAST ast) {
         final DetailAST whitespaceFollowedAst = getWhitespaceFollowedNode(ast);
 
-        if (whitespaceFollowedAst.getNextSibling() == null
-                || whitespaceFollowedAst.getNextSibling().getType() != TokenTypes.ANNOTATIONS) {
+        if (shouldCheckWhitespaceAfter(whitespaceFollowedAst)) {
             final int whitespaceColumnNo = getPositionAfter(whitespaceFollowedAst);
             final int whitespaceLineNo = whitespaceFollowedAst.getLineNo();
 
@@ -206,6 +205,27 @@ private static DetailAST getWhitespaceFollowedNode(DetailAST ast) {
         return whitespaceFollowedAst;
     }
 
+    /**
+     * Returns whether whitespace after a visited node should be checked. For example, whitespace
+     * is not allowed between a type and an array declarator (returns true), except when there is
+     * an annotation in between the type and array declarator (returns false).
+     * @param ast the visited node
+     * @return true if whitespace after ast should be checked
+     */
+    private static boolean shouldCheckWhitespaceAfter(DetailAST ast) {
+        boolean checkWhitespace = true;
+        final DetailAST sibling = ast.getNextSibling();
+        if (sibling != null) {
+            if (sibling.getType() == TokenTypes.ANNOTATIONS) {
+                checkWhitespace = false;
+            }
+            else if (sibling.getType() == TokenTypes.ARRAY_DECLARATOR) {
+                checkWhitespace = sibling.getFirstChild().getType() != TokenTypes.ANNOTATIONS;
+            }
+        }
+        return checkWhitespace;
+    }
+
     /**
      * Gets position after token (place of possible redundant whitespace).
      * @param ast Node representing token.

src/main/resources/com/puppycrawl/tools/checkstyle/grammar/java.g

@@ -257,6 +257,14 @@ typeSpec[boolean addImagNode]
     | builtInTypeSpec[addImagNode]
     ;
 
+// A type specification for a variable length parameter is a type name with
+// possible brackets afterwards that can end with annotations.
+variableLengthParameterTypeSpec
+    :   (classOrInterfaceType[false] | builtInType)
+        ({LA(1) == AT}? annotations | )
+        (lb:LBRACK^ {#lb.setType(ARRAY_DECLARATOR);} RBRACK ({LA(1) == AT}? annotations | ))*
+    ;
+
 // A class type specification is a class type with either:
 // - possible brackets afterwards
 //   (which would make it an array type).
@@ -387,8 +395,8 @@ builtInTypeSpec[boolean addImagNode]
 // A type name. which is either a (possibly qualified and parameterized)
 // class name or a primitive (builtin) type
 type
-    :    classOrInterfaceType[false]
-    |    builtInType
+    :    ({LA(1) == AT}? annotations | )
+         (classOrInterfaceType[false] | builtInType)
     ;
 
 /** A declaration is the creation of a reference or primitive-type variable
@@ -893,9 +901,11 @@ variableDeclarator![AST mods, AST t]
         {#variableDeclarator = #(#[VARIABLE_DEF,"VARIABLE_DEF"], mods, #(#[TYPE,"TYPE"],d), id, v);}
     ;
 
-declaratorBrackets[AST typ]
-    :    {#declaratorBrackets=typ;}
-        (lb:LBRACK^ {#lb.setType(ARRAY_DECLARATOR);} RBRACK)*
+declaratorBrackets![AST typ]
+    :    ({LA(1) == AT}? an:annotations | ) lb:LBRACK {#lb.setType(ARRAY_DECLARATOR);} rb:RBRACK
+         db:declaratorBrackets[#(lb, typ, an, rb)]
+        {#declaratorBrackets = #db;}
+    |   {#declaratorBrackets = typ;}
     ;
 
 varInitializer
@@ -969,7 +979,7 @@ parameterDeclarationList
     ;
 
 variableLengthParameterDeclaration!
-    :    pm:parameterModifier t:typeSpec[false] td:ELLIPSIS IDENT
+    :    pm:parameterModifier t:variableLengthParameterTypeSpec td:ELLIPSIS IDENT
         pd:declaratorBrackets[#t]
         {#variableLengthParameterDeclaration = #(#[PARAMETER_DEF,"PARAMETER_DEF"],
                                                 pm, #([TYPE,"TYPE"],pd), td, IDENT);}
@@ -1592,6 +1602,7 @@ newArrayDeclarator
                 warnWhenFollowAmbig = false;
             }
         :
+            ({LA(1) == AT}? annotations | )
             lb:LBRACK^ {#lb.setType(ARRAY_DECLARATOR);}
                 (expression)?
             RBRACK

src/test/java/com/puppycrawl/tools/checkstyle/grammar/AstRegressionTest.java

@@ -68,6 +68,12 @@ public void testJava8ClassAstTree1() throws Exception {
                 getPath("InputRegressionJava8Class1.java"));
     }
 
+    @Test
+    public void testJava8ClassAstTree2() throws Exception {
+        verifyAst(getPath("InputRegressionJava8Class2Ast.txt"),
+                getPath("InputRegressionJava8Class2.java"));
+    }
+
     @Test
     public void testInputSemicolonBetweenImports() throws Exception {
         verifyAst(getPath("InputSemicolonBetweenImportsAst.txt"),

src/test/java/com/puppycrawl/tools/checkstyle/grammar/java8/AnnotationTest.java

@@ -132,4 +132,13 @@ public void testAnnotationInTypeParameters()
         verify(checkConfig, getPath("InputAnnotations11.java"), expected);
     }
 
+    @Test
+    public void testAnnotationOnVarargs()
+            throws Exception {
+        final DefaultConfiguration checkConfig =
+                createModuleConfig(MemberNameCheck.class);
+        final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
+        verify(checkConfig, getPath("InputAnnotations12.java"), expected);
+    }
+
 }

src/test/resources/com/puppycrawl/tools/checkstyle/checks/whitespace/nowhitespaceafter/InputNoWhitespaceAfterArrayDeclarations3.java

@@ -9,6 +9,9 @@ public void testWithAnnotationInMiddle1(final char @AnnotationAfterTest [] a) {}
     public void testWithAnnotationInMiddle2(final char@AnnotationAfterTest [] a) {}//Correct
     public void testWithAnnotationInMiddle3(final char @AnnotationAfterTest[] a) {}//Correct
     public void testWithAnnotationInMiddle4(final char@AnnotationAfterTest[]a) {}//Correct
+    public @AnnotationAfterTest String @AnnotationAfterTest [] testWithAnnotationInMiddle5() {
+        return new @AnnotationAfterTest String @AnnotationAfterTest [3];//Correct
+    }
 
     @Target(ElementType.TYPE_USE)
     @interface AnnotationAfterTest {

src/test/resources/com/puppycrawl/tools/checkstyle/grammar/InputRegressionJava8Class2.java

@@ -0,0 +1,38 @@
+//start line index in expected file is 2
+package com.puppycrawl.tools.checkstyle.grammar;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.Map;
+import java.util.List;
+import java.util.function.IntBinaryOperator;
+import java.util.function.Predicate;
+import java.util.function.Supplier;
+
+public class InputRegressionJava8Class2 {
+    static class Inner1 { static class Inner2<V> { public void m() {} } }
+    static class Inner3<T> { public void m() {} }
+
+    public void m1(@MyAnnotation String @MyAnnotation ... vararg) {}
+    public String m2() @MyAnnotation [] @MyAnnotation [] { return null; }    
+
+    public void instructions() {
+        // annotations
+        Map.@MyAnnotation Entry e;
+        String str = (@MyAnnotation String) "";
+        (new Inner3()).<@MyAnnotation String>m();
+        Object arr = new @MyAnnotation String @MyAnnotation [3];
+        for (String a @MyAnnotation [] : m2()) {}
+        Object arr2 = new @MyAnnotation int[3];        
+    }
+}
+
+@Retention(RetentionPolicy.CLASS)
+@Target({ ElementType.TYPE_USE })
+@interface MyAnnotation {
+}