Issue checkstyle#13988: Support unnamed variables

piyush-1234 · Feb 4, 2024 · a645157 · a645157
1 parent 680e6b8
commit a645157
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Showing 13 changed files with 2,141 additions and 16 deletions.
diff --git a/config/projects-to-test/openjdk21-excluded.files b/config/projects-to-test/openjdk21-excluded.files
@@ -54,12 +54,6 @@
   <property name="fileNamePattern" value="[\\/]test[\\/]langtools[\\/]tools[\\/]javac[\\/]unnamedclass[\\/]NestedEnum.java$"/>
 </module>
 
-<!-- until https://github.com/checkstyle/checkstyle/issues/13988 -->
-<module name="BeforeExecutionExclusionFileFilter">
-  <property name="fileNamePattern" value="[\\/]test[\\/]langtools[\\/]tools[\\/]javac[\\/]patterns[\\/]Unnamed.java$"/>
-</module>
-
-
 <!-- non-compilable -->
 <module name="BeforeExecutionExclusionFileFilter">
   <property name="fileNamePattern" value="[\\/]test[\\/]langtools[\\/]tools[\\/]javac[\\/]diags[\\/]examples[\\/]UnnamedClassNoMain.java$"/>

diff --git a/src/main/java/com/puppycrawl/tools/checkstyle/JavaAstVisitor.java b/src/main/java/com/puppycrawl/tools/checkstyle/JavaAstVisitor.java
@@ -2239,8 +2239,8 @@ public DetailAstImpl visitRecordPatternDef(JavaLanguageParser.RecordPatternDefCo
     }
 
     @Override
-    public DetailAstImpl visitTypePattern(
-            JavaLanguageParser.TypePatternContext ctx) {
+    public DetailAstImpl visitTypePatternDef(
+            JavaLanguageParser.TypePatternDefContext ctx) {
         final DetailAstImpl type = visit(ctx.type);
         final DetailAstImpl patternVariableDef = createImaginary(TokenTypes.PATTERN_VARIABLE_DEF);
         patternVariableDef.addChild(createModifiers(ctx.mods));
@@ -2249,6 +2249,11 @@ public DetailAstImpl visitTypePattern(
         return patternVariableDef;
     }
 
+    @Override
+    public DetailAstImpl visitUnnamedPatternDef(JavaLanguageParser.UnnamedPatternDefContext ctx) {
+        return create(TokenTypes.UNNAMED_PATTERN_DEF, ctx.start);
+    }
+
     @Override
     public DetailAstImpl visitRecordPattern(JavaLanguageParser.RecordPatternContext ctx) {
         final DetailAstImpl recordPattern = createImaginary(TokenTypes.RECORD_PATTERN_DEF);

diff --git a/src/main/java/com/puppycrawl/tools/checkstyle/api/TokenTypes.java b/src/main/java/com/puppycrawl/tools/checkstyle/api/TokenTypes.java
@@ -6743,6 +6743,46 @@ public final class TokenTypes {
     public static final int EMBEDDED_EXPRESSION_END =
             JavaLanguageLexer.EMBEDDED_EXPRESSION_END;
 
+    /**
+     * An unnamed pattern variable definition. Appears as part of a pattern definition.
+     * <p>For example:</p>
+     * <pre>
+     *    if (r instanceof R(_)) {}
+     * </pre>
+     * <p>parses as:</p>
+     * <pre>
+     * LITERAL_IF -&gt; if
+     *  |--LPAREN -&gt; (
+     *  |--EXPR -&gt; EXPR
+     *  |   `--LITERAL_INSTANCEOF -&gt; instanceof
+     *  |       |--IDENT -&gt; r
+     *  |       `--RECORD_PATTERN_DEF -&gt; RECORD_PATTERN_DEF
+     *  |           |--MODIFIERS -&gt; MODIFIERS
+     *  |           |--TYPE -&gt; TYPE
+     *  |           |   `--IDENT -&gt; R
+     *  |           |--LPAREN -&gt; (
+     *  |           |--RECORD_PATTERN_COMPONENTS -&gt; RECORD_PATTERN_COMPONENTS
+     *  |           |   `--UNNAMED_PATTERN_DEF -&gt; _
+     *  |           `--RPAREN -&gt; )
+     *  |--RPAREN -&gt; )
+     *  `--SLIST -&gt; {
+     *      `--RCURLY -&gt; }
+     * </pre>
+     *
+     * @see #RECORD_PATTERN_COMPONENTS
+     * @see #RECORD_PATTERN_DEF
+     * @see #LITERAL_SWITCH
+     * @see #LITERAL_INSTANCEOF
+     * @see #SWITCH_RULE
+     * @see #LITERAL_WHEN
+     * @see #PATTERN_VARIABLE_DEF
+     * @see #PATTERN_DEF
+     *
+     * @since 10.14.0
+     */
+    public static final int UNNAMED_PATTERN_DEF =
+            JavaLanguageLexer.UNNAMED_PATTERN_DEF;
+
     /** Prevent instantiation. */
     private TokenTypes() {
     }

diff --git a/src/main/resources/com/puppycrawl/tools/checkstyle/grammar/java/JavaLanguageLexer.g4 b/src/main/resources/com/puppycrawl/tools/checkstyle/grammar/java/JavaLanguageLexer.g4
@@ -114,7 +114,9 @@ tokens {
 
     STRING_TEMPLATE_BEGIN, STRING_TEMPLATE_MID, STRING_TEMPLATE_END,
     STRING_TEMPLATE_CONTENT, EMBEDDED_EXPRESSION_BEGIN, EMBEDDED_EXPRESSION,
-    EMBEDDED_EXPRESSION_END
+    EMBEDDED_EXPRESSION_END,
+
+    LITERAL_UNDERSCORE, UNNAMED_PATTERN_DEF
 }
 
 @header {
@@ -213,6 +215,7 @@ LITERAL_NON_SEALED:      'non-sealed';
 LITERAL_SEALED:          'sealed';
 LITERAL_PERMITS:         'permits';
 LITERAL_WHEN:            'when';
+LITERAL_UNDERSCORE:      '_';
 
 // Literals
 DECIMAL_LITERAL_LONG:    ('0' | [1-9] (Digits? | '_'+ Digits)) [lL];

diff --git a/src/main/resources/com/puppycrawl/tools/checkstyle/grammar/java/JavaLanguageParser.g4 b/src/main/resources/com/puppycrawl/tools/checkstyle/grammar/java/JavaLanguageParser.g4
@@ -913,7 +913,8 @@ primaryPattern
     ;
 
 typePattern
-    : mods+=modifier* type=typeType[true] id
+    : mods+=modifier* type=typeType[true] id             #typePatternDef
+    | LITERAL_UNDERSCORE                                 #unnamedPatternDef
     ;
 
 recordPattern
@@ -929,7 +930,8 @@ permittedSubclassesAndInterfaces
     ;
 
 // Handle the 'keyword as identifier' problem
-id  : LITERAL_RECORD
+id:  LITERAL_UNDERSCORE
+    | LITERAL_RECORD
     | LITERAL_YIELD
     | LITERAL_NON_SEALED
     | LITERAL_SEALED

diff --git a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTokenTextCheckTest.java b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTokenTextCheckTest.java
@@ -179,7 +179,7 @@ public void testOrderOfProperties() {
 
     @Test
     public void testAcceptableTokensMakeSense() {
-        final int expectedTokenTypesTotalNumber = 194;
+        final int expectedTokenTypesTotalNumber = 195;
         assertWithMessage("Total number of TokenTypes has changed, acceptable tokens in"
                 + " IllegalTokenTextCheck need to be reconsidered.")
             .that(TokenUtil.getTokenTypesTotalNumber())

diff --git a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/GeneratedJavaTokenTypesTest.java b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/GeneratedJavaTokenTypesTest.java
@@ -736,6 +736,12 @@ public void testTokenNumbering() {
         assertWithMessage(message)
             .that(JavaLanguageLexer.EMBEDDED_EXPRESSION_END)
             .isEqualTo(223);
+        assertWithMessage(message)
+            .that(JavaLanguageLexer.LITERAL_UNDERSCORE)
+            .isEqualTo(224);
+        assertWithMessage(message)
+            .that(JavaLanguageLexer.UNNAMED_PATTERN_DEF)
+            .isEqualTo(225);
 
         final int tokenCount = (int) Arrays.stream(JavaLanguageLexer.class.getDeclaredFields())
                 .filter(GeneratedJavaTokenTypesTest::isPublicStaticFinalInt)
@@ -746,7 +752,7 @@ public void testTokenNumbering() {
                         + " 'GeneratedJavaTokenTypesTest' and verified"
                         + " that their old numbering didn't change")
             .that(tokenCount)
-            .isEqualTo(235);
+            .isEqualTo(237);
     }
 
     /**

diff --git a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java21/Java21AstRegressionTest.java b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java21/Java21AstRegressionTest.java
@@ -54,4 +54,22 @@ public void testBasicStringTemplateWithTabs() throws Exception {
                         "InputStringTemplateBasicWithTabs.java"));
     }
 
+    @Test
+    public void testUnnamedVariableBasic() throws Exception {
+        verifyAst(
+                getNonCompilablePath(
+                        "ExpectedUnnamedVariableBasic.txt"),
+                getNonCompilablePath(
+                        "InputUnnamedVariableBasic.java"));
+    }
+
+    @Test
+    public void testUnnamedVariableSwitch() throws Exception {
+        verifyAst(
+                getNonCompilablePath(
+                        "ExpectedUnnamedVariableSwitch.txt"),
+                getNonCompilablePath(
+                        "InputUnnamedVariableSwitch.java"));
+    }
+
 }
diff --git a/src/test/java/com/puppycrawl/tools/checkstyle/utils/TokenUtilTest.java b/src/test/java/com/puppycrawl/tools/checkstyle/utils/TokenUtilTest.java
@@ -228,7 +228,7 @@ public void testGetTokenTypesTotalNumber() {
 
         assertWithMessage("Invalid token total number")
             .that(tokenTypesTotalNumber)
-            .isEqualTo(194);
+            .isEqualTo(195);
     }
 
     @Test
@@ -238,10 +238,10 @@ public void testGetAllTokenIds() {
 
         assertWithMessage("Invalid token length")
             .that(allTokenIds.length)
-            .isEqualTo(194);
+            .isEqualTo(195);
         assertWithMessage("invalid sum")
             .that(sum)
-            .isEqualTo(20917);
+            .isEqualTo(21142);
     }
 
     @Test