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vivek-0509romani
vivek-0509
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romani
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Issue #18283: allow unnamed variables (_) in naming patterns
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6 files changed

+114
-4
lines changed

6 files changed

+114
-4
lines changed

‎src/it/java/com/google/checkstyle/test/chapter5naming/rule527localvariablenames/LocalVariableNamesTest.java‎

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@@ -52,4 +52,14 @@ public void testOneChar() throws Exception {
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verifyWithWholeConfig(getPath("InputLocalVariableNameOneCharVarName.java"));
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}
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@Test
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public void testUnnamedVariables() throws Exception {
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verifyWithWholeConfig(getPath("InputUnnamedVariables.java"));
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}
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@Test
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public void testPatternVariableNameUnnamed() throws Exception {
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verifyWithWholeConfig(getPath("InputPatternVariableNameUnnamed.java"));
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}
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}

‎src/it/resources/com/google/checkstyle/test/chapter5naming/rule526parameternames/InputCatchParameterName.java‎

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@@ -94,5 +94,26 @@ public class InputCatchParameterName {
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/* foo */
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} catch (Exception Ex) { // violation 'Catch parameter name 'Ex' must match pattern'
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}
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try {
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/* foo */
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} catch (Exception _) {
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// handle
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}
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try {
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/* foo */
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} catch (Exception _ex) { // violation 'Catch parameter name '_ex' must match pattern'
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}
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try {
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/* foo */
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} catch (Exception e_x) { // violation 'Catch parameter name 'e_x' must match pattern'
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}
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try {
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/* foo */
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} catch (Exception ex_) { // violation 'Catch parameter name 'ex_' must match pattern'
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}
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}
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}

‎src/it/resources/com/google/checkstyle/test/chapter5naming/rule526parameternames/InputLambdaParameterName.java‎

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Original file line numberDiff line numberDiff line change
@@ -28,4 +28,15 @@ public class InputLambdaParameterName {
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BiFunction<String, String, Integer> goodNamedParameters =
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(first, second) -> (first + second).length();
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BiFunction<String, String, String> unnamedParam = (first, _) -> first;
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BiFunction<String, String, String> underscoreStart =
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(first, _second) -> first; // violation 'Lambda parameter name '_second' must match pattern'
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BiFunction<String, String, String> underscoreMiddle =
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(first, sec_ond) -> first; // violation 'Lambda parameter name 'sec_ond' must match pattern'
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BiFunction<String, String, String> underscoreEnd =
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(first, second_) -> first; // violation 'Lambda parameter name 'second_' must match pattern'
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}

‎src/it/resources/com/google/checkstyle/test/chapter5naming/rule527localvariablenames/InputPatternVariableNameUnnamed.java‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,28 @@
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// Java22
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package com.google.checkstyle.test.chapter5naming.rule527localvariablenames;
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/** Tests unnamed pattern variables. */
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public class InputPatternVariableNameUnnamed {
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void test(Object o1) {
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if (o1 instanceof String _) {
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System.out.println("ok");
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}
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// violation below 'Pattern variable name '_s' must match pattern'
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if (o1 instanceof String _s) {
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System.out.println(_s);
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}
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// violation below 'Pattern variable name 's_t' must match pattern'
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if (o1 instanceof String s_t) {
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System.out.println(s_t);
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}
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// violation below 'Pattern variable name 'st_' must match pattern'
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if (o1 instanceof String st_) {
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System.out.println(st_);
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}
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}
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}

‎src/it/resources/com/google/checkstyle/test/chapter5naming/rule527localvariablenames/InputUnnamedVariables.java‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,40 @@
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// Java22
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package com.google.checkstyle.test.chapter5naming.rule527localvariablenames;
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import java.util.HashMap;
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/** Tests that unnamed variables (_) are allowed per Google Style. */
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public class InputUnnamedVariables {
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record Point(int x, int y) {}
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void testUnnamedVariables() {
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for (var _ : new String[] {"foo"}) {
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System.out.println("iteration");
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}
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var _ = new Thread();
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switch ("foo") {
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case String _ -> System.out.println("bar");
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}
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switch (new Point(0, 0)) {
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case Point(int _, _) -> System.out.println("point");
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}
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try {
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// something
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} catch (Error _) {
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// error handling
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}
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var map = new HashMap<String, Integer>();
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map.computeIfAbsent("foo", _ -> 23);
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var _name = "test"; // violation 'Local variable name '_name' must match pattern'
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var na_me = "test"; // violation 'Local variable name 'na_me' must match pattern'
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var name_ = "test"; // violation 'Local variable name 'name_' must match pattern'
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}
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}

‎src/main/resources/google_checks.xml‎

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Original file line numberDiff line numberDiff line change
@@ -265,22 +265,22 @@
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value="Parameter name ''{0}'' must match pattern ''{1}''."/>
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</module>
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<module name="LambdaParameterName">
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<property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
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<property name="format" value="^(_|[a-z]([a-z0-9][a-zA-Z0-9]*)?)$"/>
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<message key="name.invalidPattern"
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value="Lambda parameter name ''{0}'' must match pattern ''{1}''."/>
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</module>
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<module name="CatchParameterName">
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<property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
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<property name="format" value="^(_|[a-z]([a-z0-9][a-zA-Z0-9]*)?)$"/>
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<message key="name.invalidPattern"
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value="Catch parameter name ''{0}'' must match pattern ''{1}''."/>
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</module>
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<module name="LocalVariableName">
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<property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
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<property name="format" value="^(_|[a-z]([a-z0-9][a-zA-Z0-9]*)?)$"/>
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<message key="name.invalidPattern"
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value="Local variable name ''{0}'' must match pattern ''{1}''."/>
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</module>
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<module name="PatternVariableName">
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<property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
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<property name="format" value="^(_|[a-z]([a-z0-9][a-zA-Z0-9]*)?)$"/>
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<message key="name.invalidPattern"
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value="Pattern variable name ''{0}'' must match pattern ''{1}''."/>
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</module>

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