Issue checkstyle#4639: added support for lambdas in UnnecessaryParent…

…heses
ArneLimburg · Aug 23, 2017 · 1b7bd7d · 1b7bd7d
1 parent e15a50d
commit 1b7bd7d
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Showing 13 changed files with 144 additions and 3 deletions.
diff --git a/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessaryParenthesesCheck.java b/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessaryParenthesesCheck.java
@@ -89,6 +89,12 @@ public class UnnecessaryParenthesesCheck extends AbstractCheck {
      */
     public static final String MSG_RETURN = "unnecessary.paren.return";
 
+    /**
+     * A key is pointing to the warning message text in "messages.properties"
+     * file.
+     */
+    public static final String MSG_LAMBDA = "unnecessary.paren.lambda";
+
     /** The maximum string length before we chop the string. */
     private static final int MAX_QUOTED_LENGTH = 25;
 
@@ -153,6 +159,7 @@ public int[] getDefaultTokens() {
             TokenTypes.SL_ASSIGN,
             TokenTypes.SR_ASSIGN,
             TokenTypes.STAR_ASSIGN,
+            TokenTypes.LAMBDA,
         };
     }
 
@@ -181,6 +188,7 @@ public int[] getAcceptableTokens() {
             TokenTypes.SL_ASSIGN,
             TokenTypes.SR_ASSIGN,
             TokenTypes.STAR_ASSIGN,
+            TokenTypes.LAMBDA,
         };
     }
 
@@ -190,12 +198,16 @@ public int[] getRequiredTokens() {
         return CommonUtils.EMPTY_INT_ARRAY;
     }
 
+    // -@cs[CyclomaticComplexity] All logs should be in visit token.
     @Override
     public void visitToken(DetailAST ast) {
         final int type = ast.getType();
         final DetailAST parent = ast.getParent();
 
-        if (type != TokenTypes.ASSIGN
+        if (type == TokenTypes.LAMBDA && isLambdaSingleParameterSurrounded(ast)) {
+            log(ast, MSG_LAMBDA, ast.getText());
+        }
+        else if (type != TokenTypes.ASSIGN
             || parent.getType() != TokenTypes.ANNOTATION_MEMBER_VALUE_PAIR) {
 
             final boolean surrounded = isSurrounded(ast);
@@ -291,6 +303,22 @@ private static boolean isExprSurrounded(DetailAST ast) {
         return ast.getFirstChild().getType() == TokenTypes.LPAREN;
     }
 
+    /**
+     * Tests if the given lambda node has a single parameter, no defined type, and is surrounded
+     * by parentheses.
+     * @param ast a {@code DetailAST} whose type is
+     *        {@code TokenTypes.LAMBDA}.
+     * @return {@code true} if the lambda has a single parameter, no defined type, and is
+     *         surrounded by parentheses.
+     */
+    private static boolean isLambdaSingleParameterSurrounded(DetailAST ast) {
+        final DetailAST firstChild = ast.getFirstChild();
+        return firstChild.getType() == TokenTypes.LPAREN
+                && firstChild.getNextSibling().getChildCount(TokenTypes.PARAMETER_DEF) == 1
+                && firstChild.getNextSibling().getFirstChild().findFirstToken(TokenTypes.TYPE)
+                        .getChildCount() == 0;
+    }
+
     /**
      * Check if the given token type can be found in an array of token types.
      * @param type the token type.

diff --git a/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages.properties b/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages.properties
@@ -51,6 +51,7 @@ string.literal.equality=Literal Strings should be compared using equals(), not '
 unnecessary.paren.assign=Unnecessary parentheses around assignment right-hand side.
 unnecessary.paren.expr=Unnecessary parentheses around expression.
 unnecessary.paren.ident=Unnecessary parentheses around identifier ''{0}''.
+unnecessary.paren.lambda=Unnecessary parentheses around lambda value.
 unnecessary.paren.literal=Unnecessary parentheses around literal ''{0}''.
 unnecessary.paren.return=Unnecessary parentheses around return value.
 unnecessary.paren.string=Unnecessary parentheses around string {0}.

diff --git a/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_de.properties b/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_de.properties
@@ -51,6 +51,7 @@ string.literal.equality=Der Vergleich von String-Literalen sollte mit equals() e
 unnecessary.paren.assign=Überflüssige Klammern um die rechte Seite der Zuweisung.
 unnecessary.paren.expr=Überflüssige Klammern um den Ausdruck.
 unnecessary.paren.ident=Überflüssige Klammern um den Bezeichner ''{0}''.
+unnecessary.paren.lambda=Überflüssige Klammern um Lambdawert.
 unnecessary.paren.literal=Überflüssige Klammern um das Literal ''{0}''.
 unnecessary.paren.return=Überflüssige Klammern um den Rückgabewert.
 unnecessary.paren.string=Überflüssige Klammern um den String ''{0}''.

diff --git a/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_es.properties b/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_es.properties
@@ -51,6 +51,7 @@ string.literal.equality=Las cadenas literales deben compararse usando equals(),
 unnecessary.paren.assign=Paréntesis innecesarios alrededor de la parte derecha de una asignación.
 unnecessary.paren.expr=Paréntesis innecesarios alrededor de la expresión.
 unnecessary.paren.ident=Paréntesis innecesarios alrededor del identificador ''{0}''.
+unnecessary.paren.lambda=Paréntesis innecesarios alrededor del valor lambda.
 unnecessary.paren.literal=Paréntesis innecesarios alrededor del literal ''{0}''.
 unnecessary.paren.return=Paréntesis innecesarios alrededor del valor de retorno.
 unnecessary.paren.string=Paréntesis innecesarios alrededor de la cadena {0}.

diff --git a/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_fi.properties b/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_fi.properties
@@ -51,6 +51,7 @@ string.literal.equality=Kirjaimellinen Strings pitäisi verrata käyttämällä
 unnecessary.paren.assign=Tarpeettomia sulkuja noin tehtävän oikealla puolella.
 unnecessary.paren.expr=Tarpeettomia sulkuja noin ilme.
 unnecessary.paren.ident=Tarpeettomia sulkuja noin tunniste ''{0}''.
+unnecessary.paren.lambda=Tarpeettomat sulkeet lambda-arvon ympärillä.
 unnecessary.paren.literal=Tarpeettomia sulkuja noin kirjaimellisesti ''{0}''.
 unnecessary.paren.return=Tarpeettomia sulkuja noin paluuarvo.
 unnecessary.paren.string=Tarpeettomia sulkuja noin merkkijono {0} .

diff --git a/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_fr.properties b/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_fr.properties
@@ -51,6 +51,7 @@ string.literal.equality=Les chaines de caractères littérales devraient être c
 unnecessary.paren.assign=Parenthèses inutiles autour la partie droite de l''affectation.
 unnecessary.paren.expr=Parenthèses inutiles autour de l''expression.
 unnecessary.paren.ident=Parenthèses inutiles autour de l''identifiant ''{0}''.
+unnecessary.paren.lambda=Parenthèses inutiles autour de la valeur lambda.
 unnecessary.paren.literal=Parenthèses inutiles autour de la chaîne littérale ''{0}''.
 unnecessary.paren.return=Parenthèses inutiles autour de la valeur de retour.
 unnecessary.paren.string=Parenthèses inutiles autour de la chaîne {0}.

diff --git a/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_ja.properties b/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_ja.properties
@@ -51,6 +51,7 @@ string.literal.equality=リテラルの文字列は ''{0}'' ではなく、 equa
 unnecessary.paren.assign=代入式の右辺に不要な括弧があります。
 unnecessary.paren.expr=式の前後に不要な括弧があります。
 unnecessary.paren.ident=識別子 ''{0}'' の前後に不要な括弧があります。
+unnecessary.paren.lambda=ラムダ値の周りの不必要なカッコ。
 unnecessary.paren.literal=リテラル ''{0}'' の前後に不要な括弧があります。
 unnecessary.paren.return=戻り値の前後に不要な括弧があります。
 unnecessary.paren.string=文字列 {0} の前後に不要な括弧があります。

diff --git a/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_pt.properties b/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_pt.properties
@@ -51,6 +51,7 @@ string.literal.equality=\"Strings\" literais devem ser comparadas com equals(),
 unnecessary.paren.assign=Parênteses desnecessários ao redor do lado direito atribuição.
 unnecessary.paren.expr=Parênteses desnecessários ao redor expressão.
 unnecessary.paren.ident=Parênteses desnecessários ao redor identificador ''{0}''.
+unnecessary.paren.lambda=Parêntesis desnecessários em torno do valor lambda.
 unnecessary.paren.literal=Parênteses desnecessários em torno literal ''{0}''.
 unnecessary.paren.return=Parênteses desnecessários em torno de valor de retorno.
 unnecessary.paren.string=Parênteses desnecessários em torno cadeia {0}

diff --git a/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_tr.properties b/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_tr.properties
@@ -52,6 +52,7 @@ string.literal.equality=''String'' ifadeleri ''{0}'' kullanarak değil, equals()
 unnecessary.paren.assign=Atama ifadesinin sağ tarafında gereksiz parantez mevcut.
 unnecessary.paren.expr=İfadenin etrafında gereksiz parantez mevcut.
 unnecessary.paren.ident=''{0}'' belirteçinin etrafında gereksiz parantez mevcut.
+unnecessary.paren.lambda=Lamba değeri etrafında gereksiz parantezler var.
 unnecessary.paren.literal=''{0}'' etrafında gereksiz parantez mevcut.
 unnecessary.paren.return=Geri dönüş değeri etrafında gereksiz parantez mevcut.
 unnecessary.paren.string=''{0}'' etrafında gereksiz parantez mevcut.

diff --git a/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_zh.properties b/src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_zh.properties
@@ -51,6 +51,7 @@ string.literal.equality=字符串应使用equals()方法进行比较，而非''{
 unnecessary.paren.assign=赋值语句右方不必要的小括号。
 unnecessary.paren.expr=表达式周围不必要的小括号。
 unnecessary.paren.ident=关键字 ''{0}'' 周围不必要的小括号。
+unnecessary.paren.lambda=lambda 值周围不必要的小括号。
 unnecessary.paren.literal=字符串 ''{0}'' 周围不必要的小括号。
 unnecessary.paren.return=return 值周围不必要的小括号。
 unnecessary.paren.string=字符串 {0} 周围不必要的小括号。

diff --git a/...t/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessaryParenthesesCheckTest.java b/...t/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessaryParenthesesCheckTest.java
@@ -22,6 +22,7 @@
 import static com.puppycrawl.tools.checkstyle.checks.coding.UnnecessaryParenthesesCheck.MSG_ASSIGN;
 import static com.puppycrawl.tools.checkstyle.checks.coding.UnnecessaryParenthesesCheck.MSG_EXPR;
 import static com.puppycrawl.tools.checkstyle.checks.coding.UnnecessaryParenthesesCheck.MSG_IDENT;
+import static com.puppycrawl.tools.checkstyle.checks.coding.UnnecessaryParenthesesCheck.MSG_LAMBDA;
 import static com.puppycrawl.tools.checkstyle.checks.coding.UnnecessaryParenthesesCheck.MSG_LITERAL;
 import static com.puppycrawl.tools.checkstyle.checks.coding.UnnecessaryParenthesesCheck.MSG_RETURN;
 import static com.puppycrawl.tools.checkstyle.checks.coding.UnnecessaryParenthesesCheck.MSG_STRING;
@@ -107,6 +108,24 @@ public void test15Extensions() throws Exception {
         verify(checkConfig, getPath("InputUnnecessaryParentheses15Extensions.java"), expected);
     }
 
+    @Test
+    public void testLambdas() throws Exception {
+        final DefaultConfiguration checkConfig =
+            createModuleConfig(UnnecessaryParenthesesCheck.class);
+        checkConfig.addAttribute("tokens", "LAMBDA");
+        final String[] expected = {
+            "10:35: " + getCheckMessage(MSG_LAMBDA),
+            "11:35: " + getCheckMessage(MSG_LAMBDA),
+            "18:18: " + getCheckMessage(MSG_LAMBDA),
+            "19:57: " + getCheckMessage(MSG_LAMBDA),
+            "38:25: " + getCheckMessage(MSG_LAMBDA),
+            "38:33: " + getCheckMessage(MSG_LAMBDA),
+            "41:25: " + getCheckMessage(MSG_LAMBDA),
+            "44:31: " + getCheckMessage(MSG_LAMBDA),
+        };
+        verify(checkConfig, getPath("InputUnnecessaryParenthesesLambdas.java"), expected);
+    }
+
     @Test
     public void testTokensNotNull() {
         final UnnecessaryParenthesesCheck check = new UnnecessaryParenthesesCheck();

diff --git a/...s/checkstyle/checks/coding/unnecessaryparentheses/InputUnnecessaryParenthesesLambdas.java b/...s/checkstyle/checks/coding/unnecessaryparentheses/InputUnnecessaryParenthesesLambdas.java
@@ -0,0 +1,79 @@
+package com.puppycrawl.tools.checkstyle.checks.coding.unnecessaryparentheses;
+
+import java.io.Serializable;
+import java.util.HashSet;
+import java.util.Objects;
+import java.util.function.Function;
+
+public class InputUnnecessaryParenthesesLambdas {
+    int foo(int y) {
+        MathOperation case1 = (x) -> x + x;
+        MathOperation case2 = (x) -> { return x + x; };
+        MathOperation case3 = (int x) -> x + x;
+        MathOperation case4 = x -> x + x;
+        MathOperation2 case5 = (a, b) -> a + b;
+        MathOperation2 case6 = (int a, int b) -> a + b;
+        MathOperation2 case7 = (int a, int b) -> { return a + b; };
+        Objects.requireNonNull(null, () -> "message");
+        call((x) -> x + x);
+        new HashSet<Integer>().stream().filter((filter) -> filter > 0);
+        return y;
+    }
+
+    static <T> CheckedFunction1<T, T> identitity() {
+        return t -> t;
+    }
+
+    public interface CheckedFunction2<T1, T2, R> extends Lambda<R> {
+        R apply(T1 t1, T2 t2) throws Throwable;
+
+        default CheckedFunction1<T2, R> apply(T1 t1) {
+            return (T2 t2) -> apply(t1, t2);
+        }
+        @Override
+        default Function1<T1, CheckedFunction1<T2, R>> curried() {
+                    return t1 -> t2 -> apply(t1, t2);
+        }
+        default Function1<T1, CheckedFunction1<T2, R>> curried2() {
+            return (t1) -> (t2) -> apply(t1, t2);
+        }
+        default Function1<T1, CheckedFunction1<T2, R>> curried3() {
+            return (t1) -> t2 -> apply(t1, t2);
+        }
+        default Function1<T1, CheckedFunction1<T2, R>> curried4() {
+            return t1 -> (t2) -> apply(t1, t2);
+        }
+    }
+
+    private void call(MathOperation o) {
+        o.operation(1);
+    }
+
+    interface MathOperation {
+        int operation(int a);
+    }
+
+    interface MathOperation2 {
+        int operation(int a, int b);
+    }
+
+    interface Lambda<R> extends Serializable {
+        Lambda<?> curried();
+    }
+
+    public interface Function1<T1, R> extends Lambda<R>, Function<T1, R> {
+        @Override
+        default Function1<T1, R> curried() {
+            return this;
+        }
+    }
+
+    public interface CheckedFunction1<T1, R> extends Lambda<R> {
+        R apply(T1 t1) throws Throwable;
+
+        @Override
+        default CheckedFunction1<T1, R> curried() {
+            return this;
+        }
+    }
+}
diff --git a/src/xdocs/config_coding.xml b/src/xdocs/config_coding.xml
@@ -4365,7 +4365,8 @@ if (&quot;something&quot;.equals(x))
                     <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#PLUS_ASSIGN">PLUS_ASSIGN</a>,
                     <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#SL_ASSIGN">SL_ASSIGN</a>,
                     <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#SR_ASSIGN">SR_ASSIGN</a>,
-                    <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#STAR_ASSIGN">STAR_ASSIGN</a>.
+                    <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#STAR_ASSIGN">STAR_ASSIGN</a>,
+                    <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LAMBDA">LAMBDA</a>.
                   </td>
                   <td>
                     <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#EXPR">EXPR</a>,
@@ -4389,7 +4390,8 @@ if (&quot;something&quot;.equals(x))
                     <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#PLUS_ASSIGN">PLUS_ASSIGN</a>,
                     <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#SL_ASSIGN">SL_ASSIGN</a>,
                     <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#SR_ASSIGN">SR_ASSIGN</a>,
-                    <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#STAR_ASSIGN">STAR_ASSIGN</a>.
+                    <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#STAR_ASSIGN">STAR_ASSIGN</a>,
+                    <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LAMBDA">LAMBDA</a>.
                   </td>
                   <td>3.4</td>
               </tr>
@@ -4428,6 +4430,10 @@ if (&quot;something&quot;.equals(x))
             <a href="https://github.com/search?q=path%3Asrc%2Fmain%2Fresources%2Fcom%2Fpuppycrawl%2Ftools%2Fcheckstyle%2Fchecks%2Fcoding+filename%3Amessages*.properties+repo%3Acheckstyle%2Fcheckstyle+%22unnecessary.paren.ident%22">
             unnecessary.paren.ident</a>
           </li>
+          <li>
+            <a href="https://github.com/search?q=path%3Asrc%2Fmain%2Fresources%2Fcom%2Fpuppycrawl%2Ftools%2Fcheckstyle%2Fchecks%2Fcoding+filename%3Amessages*.properties+repo%3Acheckstyle%2Fcheckstyle+%22unnecessary.paren.lambda%22">
+            unnecessary.paren.lambda</a>
+          </li>
           <li>
             <a href="https://github.com/search?q=path%3Asrc%2Fmain%2Fresources%2Fcom%2Fpuppycrawl%2Ftools%2Fcheckstyle%2Fchecks%2Fcoding+filename%3Amessages*.properties+repo%3Acheckstyle%2Fcheckstyle+%22unnecessary.paren.literal%22">
             unnecessary.paren.literal</a>