Issue #12101: move global locale to localized message

.ci/checker-framework-suppressions/checker-framework-nullness-optional-interning-suppressions.xml

@@ -1279,7 +1279,7 @@
     <fileName>checkstyle/src/main/java/com/puppycrawl/tools/checkstyle/LocalizedMessage.java</fileName>
     <specifier>argument</specifier>
     <message>incompatible argument for parameter loader of getBundle.</message>
-    <lineContent>return ResourceBundle.getBundle(bundle, locale, sourceClass.getClassLoader(),</lineContent>
+    <lineContent>return ResourceBundle.getBundle(bundle, sLocale, sourceClass.getClassLoader(),</lineContent>
     <details>
       found   : @Initialized @Nullable ClassLoader
       required: @Initialized @NonNull ClassLoader
@@ -1323,17 +1323,6 @@
     </details>
   </checkerFrameworkError>
 
-  <checkerFrameworkError unstable="false">
-    <fileName>checkstyle/src/main/java/com/puppycrawl/tools/checkstyle/api/Violation.java</fileName>
-    <specifier>return</specifier>
-    <message>incompatible types in return.</message>
-    <lineContent>return violation;</lineContent>
-    <details>
-      type of expression: @Initialized @Nullable String
-      method return type: @Initialized @NonNull String
-    </details>
-  </checkerFrameworkError>
-
   <checkerFrameworkError unstable="false">
     <fileName>checkstyle/src/main/java/com/puppycrawl/tools/checkstyle/checks/AvoidEscapedUnicodeCharactersCheck.java</fileName>
     <specifier>initialization.field.uninitialized</specifier>

.ci/checker-framework-suppressions/checker-framework-signature-gui-units-init-suppressions.xml

@@ -4,7 +4,7 @@
     <fileName>checkstyle/src/main/java/com/puppycrawl/tools/checkstyle/LocalizedMessage.java</fileName>
     <specifier>argument</specifier>
     <message>incompatible argument for parameter baseName of getBundle.</message>
-    <lineContent>return ResourceBundle.getBundle(bundle, locale, sourceClass.getClassLoader(),</lineContent>
+    <lineContent>return ResourceBundle.getBundle(bundle, sLocale, sourceClass.getClassLoader(),</lineContent>
     <details>
       found   : @SignatureUnknown String
       required: @BinaryName String

src/main/java/com/puppycrawl/tools/checkstyle/Checker.java

@@ -431,7 +431,7 @@ public void fireFileFinished(String fileName) {
     @Override
     protected void finishLocalSetup() throws CheckstyleException {
         final Locale locale = new Locale(localeLanguage, localeCountry);
-        Violation.setLocale(locale);
+        LocalizedMessage.setLocale(locale);
 
         if (moduleFactory == null) {
             if (moduleClassLoader == null) {

src/main/java/com/puppycrawl/tools/checkstyle/DefaultLogger.java

@@ -24,7 +24,6 @@
 import java.io.PrintWriter;
 import java.io.Writer;
 import java.nio.charset.StandardCharsets;
-import java.util.Locale;
 
 import com.puppycrawl.tools.checkstyle.api.AuditEvent;
 import com.puppycrawl.tools.checkstyle.api.AuditListener;
@@ -161,7 +160,7 @@ public void addError(AuditEvent event) {
     public void addException(AuditEvent event, Throwable throwable) {
         synchronized (errorWriter) {
             final LocalizedMessage exceptionMessage = new LocalizedMessage(
-                    Definitions.CHECKSTYLE_BUNDLE, Locale.getDefault(), DefaultLogger.class,
+                    Definitions.CHECKSTYLE_BUNDLE, DefaultLogger.class,
                     ADD_EXCEPTION_MESSAGE, event.getFileName());
             errorWriter.println(exceptionMessage.getMessage());
             throwable.printStackTrace(errorWriter);
@@ -171,7 +170,7 @@ public void addException(AuditEvent event, Throwable throwable) {
     @Override
     public void auditStarted(AuditEvent event) {
         final LocalizedMessage auditStartMessage = new LocalizedMessage(
-                Definitions.CHECKSTYLE_BUNDLE, Locale.getDefault(), DefaultLogger.class,
+                Definitions.CHECKSTYLE_BUNDLE, DefaultLogger.class,
                 AUDIT_STARTED_MESSAGE);
         infoWriter.println(auditStartMessage.getMessage());
         infoWriter.flush();
@@ -180,7 +179,7 @@ public void auditStarted(AuditEvent event) {
     @Override
     public void auditFinished(AuditEvent event) {
         final LocalizedMessage auditFinishMessage = new LocalizedMessage(
-                Definitions.CHECKSTYLE_BUNDLE, Locale.getDefault(), DefaultLogger.class,
+                Definitions.CHECKSTYLE_BUNDLE, DefaultLogger.class,
                 AUDIT_FINISHED_MESSAGE);
         infoWriter.println(auditFinishMessage.getMessage());
         closeStreams();

src/main/java/com/puppycrawl/tools/checkstyle/LocalizedMessage.java

@@ -40,14 +40,12 @@
  */
 public class LocalizedMessage {
 
+    /** The locale to localise messages to. **/
+    private static Locale sLocale = Locale.getDefault();
+
     /** Name of the resource bundle to get messages from. **/
     private final String bundle;
 
-    /**
-     * The locale to localise messages to.
-     **/
-    private final Locale locale;
-
     /** Class of the source for this message. */
     private final Class<?> sourceClass;
 
@@ -65,15 +63,13 @@ public class LocalizedMessage {
      * Creates a new {@code LocalizedMessage} instance.
      *
      * @param bundle resource bundle name
-     * @param locale The locale to localise messages to.
      * @param sourceClass the Class that is the source of the message
      * @param key the key to locate the translation.
      * @param args arguments for the translation.
      */
-    public LocalizedMessage(String bundle, Locale locale, Class<?> sourceClass, String key,
+    public LocalizedMessage(String bundle, Class<?> sourceClass, String key,
             Object... args) {
         this.bundle = bundle;
-        this.locale = locale;
         this.sourceClass = sourceClass;
         this.key = key;
         if (args == null) {
@@ -84,6 +80,20 @@ public LocalizedMessage(String bundle, Locale locale, Class<?> sourceClass, Stri
         }
     }
 
+    /**
+     * Sets a locale to use for localization.
+     *
+     * @param locale the locale to use for localization
+     */
+    public static void setLocale(Locale locale) {
+        if (Locale.ENGLISH.getLanguage().equals(locale.getLanguage())) {
+            sLocale = Locale.ROOT;
+        }
+        else {
+            sLocale = locale;
+        }
+    }
+
     /**
      * Gets the translated message.
      *
@@ -119,7 +129,7 @@ public String getMessage() {
      * @return a ResourceBundle.
      */
     private ResourceBundle getBundle() {
-        return ResourceBundle.getBundle(bundle, locale, sourceClass.getClassLoader(),
+        return ResourceBundle.getBundle(bundle, sLocale, sourceClass.getClassLoader(),
                 new Utf8Control());
     }
 

src/main/java/com/puppycrawl/tools/checkstyle/api/Violation.java

@@ -46,9 +46,6 @@ public final class Violation
     /** The default severity level if one is not specified. */
     private static final SeverityLevel DEFAULT_SEVERITY = SeverityLevel.ERROR;
 
-    /** The locale to localise violations to. **/
-    private static Locale sLocale = Locale.getDefault();
-
     /** The line number. **/
     private final int lineNo;
     /** The column number. **/
@@ -358,20 +355,6 @@ public String getSourceName() {
         return sourceClass.getName();
     }
 
-    /**
-     * Sets a locale to use for localization.
-     *
-     * @param locale the locale to use for localization
-     */
-    public static void setLocale(Locale locale) {
-        if (Locale.ENGLISH.getLanguage().equals(locale.getLanguage())) {
-            sLocale = Locale.ROOT;
-        }
-        else {
-            sLocale = locale;
-        }
-    }
-
     /**
      * Indicates whether some other object is "equal to" this one.
      * Suppression on enumeration is needed so code stays consistent.
@@ -451,7 +434,7 @@ public String getViolation() {
         String violation = getCustomViolation();
 
         if (violation == null) {
-            violation = new LocalizedMessage(bundle, sLocale, sourceClass, key, args).getMessage();
+            violation = new LocalizedMessage(bundle, sourceClass, key, args).getMessage();
         }
         return violation;
     }

src/test/java/com/puppycrawl/tools/checkstyle/CheckerTest.java

@@ -491,7 +491,7 @@ public void testFinishLocalSetupFullyInitialized() throws Exception {
             .that(context.get("basedir"))
             .isEqualTo("testBaseDir");
 
-        final Field sLocale = Violation.class.getDeclaredField("sLocale");
+        final Field sLocale = LocalizedMessage.class.getDeclaredField("sLocale");
         sLocale.setAccessible(true);
         final Locale locale = (Locale) sLocale.get(null);
         assertWithMessage("Locale is set to unexpected value")

src/test/java/com/puppycrawl/tools/checkstyle/DefaultLoggerTest.java

@@ -307,17 +307,17 @@ public void testStreamsNotClosedByLogger() throws IOException {
     }
 
     private static LocalizedMessage getAuditStartMessageClass() {
-        return new LocalizedMessage(Definitions.CHECKSTYLE_BUNDLE, Locale.getDefault(),
+        return new LocalizedMessage(Definitions.CHECKSTYLE_BUNDLE,
                 DefaultLogger.class, "DefaultLogger.auditStarted");
     }
 
     private static LocalizedMessage getAuditFinishMessageClass() {
-        return new LocalizedMessage(Definitions.CHECKSTYLE_BUNDLE, Locale.getDefault(),
+        return new LocalizedMessage(Definitions.CHECKSTYLE_BUNDLE,
                 DefaultLogger.class, "DefaultLogger.auditFinished");
     }
 
     private static LocalizedMessage getAddExceptionMessageClass(Object... arguments) {
-        return new LocalizedMessage(Definitions.CHECKSTYLE_BUNDLE, Locale.getDefault(),
+        return new LocalizedMessage(Definitions.CHECKSTYLE_BUNDLE,
                 DefaultLogger.class, "DefaultLogger.addException", arguments);
     }
 

src/test/java/com/puppycrawl/tools/checkstyle/LocalizedMessageTest.java

@@ -20,6 +20,7 @@
 package com.puppycrawl.tools.checkstyle;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static org.junit.jupiter.api.Assumptions.assumeFalse;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -30,7 +31,9 @@
 import java.util.ResourceBundle;
 import java.util.concurrent.atomic.AtomicBoolean;
 
+import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
+import org.junitpioneer.jupiter.DefaultLocale;
 
 import com.puppycrawl.tools.checkstyle.LocalizedMessage.Utf8Control;
 
@@ -45,16 +48,18 @@
  */
 public class LocalizedMessageTest {
 
+    private static final Locale DEFAULT_LOCALE = Locale.getDefault();
+
     @Test
     public void testNullArgs() {
         final LocalizedMessage messageClass = new LocalizedMessage(Definitions.CHECKSTYLE_BUNDLE,
-                Locale.getDefault(), DefaultLogger.class, "DefaultLogger.addException", "myfile");
+                DefaultLogger.class, "DefaultLogger.addException", "myfile");
         assertWithMessage("Violation should contain exception info")
                 .that(messageClass.getMessage())
                 .contains("Error auditing myfile");
 
         final LocalizedMessage nullClass = new LocalizedMessage(Definitions.CHECKSTYLE_BUNDLE,
-                Locale.getDefault(), DefaultLogger.class, "DefaultLogger.addException");
+                DefaultLogger.class, "DefaultLogger.addException");
         final String outputForNullArgs = nullClass.getMessage();
         assertWithMessage("Violation should contain exception info")
                 .that(outputForNullArgs)
@@ -206,6 +211,74 @@ protected URLConnection openConnection(URL ignore) {
                 .isNull();
     }
 
+    /**
+     * Verifies that the language specified with the system property {@code user.language} exists.
+     */
+    @Test
+    public void testLanguageIsValid() {
+        final String language = DEFAULT_LOCALE.getLanguage();
+        assumeFalse(language.isEmpty(), "Locale not set");
+        assertWithMessage("Invalid language")
+                .that(Locale.getISOLanguages())
+                .asList()
+                .contains(language);
+    }
+
+    /**
+     * Verifies that the country specified with the system property {@code user.country} exists.
+     */
+    @Test
+    public void testCountryIsValid() {
+        final String country = DEFAULT_LOCALE.getCountry();
+        assumeFalse(country.isEmpty(), "Locale not set");
+        assertWithMessage("Invalid country")
+                .that(Locale.getISOCountries())
+                .asList()
+                .contains(country);
+    }
+
+    @Test
+    public void testMessageInFrench() {
+        final LocalizedMessage violation = createSampleViolation();
+        LocalizedMessage.setLocale(Locale.FRENCH);
+
+        assertWithMessage("Invalid violation")
+            .that(violation.getMessage())
+            .isEqualTo("Instruction vide.");
+    }
+
+    @DefaultLocale("fr")
+    @Test
+    public void testEnforceEnglishLanguageBySettingUnitedStatesLocale() {
+        LocalizedMessage.setLocale(Locale.US);
+        final LocalizedMessage violation = createSampleViolation();
+
+        assertWithMessage("Invalid violation")
+            .that(violation.getMessage())
+            .isEqualTo("Empty statement.");
+    }
+
+    @DefaultLocale("fr")
+    @Test
+    public void testEnforceEnglishLanguageBySettingRootLocale() {
+        LocalizedMessage.setLocale(Locale.ROOT);
+        final LocalizedMessage violation = createSampleViolation();
+
+        assertWithMessage("Invalid violation")
+            .that(violation.getMessage())
+            .isEqualTo("Empty statement.");
+    }
+
+    private static LocalizedMessage createSampleViolation() {
+        return new LocalizedMessage("com.puppycrawl.tools.checkstyle.checks.coding.messages",
+                LocalizedMessage.class, "empty.statement");
+    }
+
+    @AfterEach
+    public void tearDown() {
+        LocalizedMessage.setLocale(DEFAULT_LOCALE);
+    }
+
     /**
      * Mocked ClassLoader for testing URL loading.
      *