raise error for empty violation store

Signed-off-by: Masoud Kiaeeha <[email protected]>

Resolves TNG#1264

archunit/src/main/java/com/tngtech/archunit/library/freeze/StoreEmptyException.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2014-2025 TNG Technology Consulting GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.tngtech.archunit.library.freeze;
+
+class StoreEmptyException extends RuntimeException {
+    StoreEmptyException(String message) {
+        super(message);
+    }
+
+}

archunit/src/main/java/com/tngtech/archunit/library/freeze/TextFileBasedViolationStore.java

@@ -73,11 +73,14 @@ public final class TextFileBasedViolationStore implements ViolationStore {
     private static final String ALLOW_STORE_CREATION_DEFAULT = "false";
     private static final String ALLOW_STORE_UPDATE_PROPERTY_NAME = "default.allowStoreUpdate";
     private static final String ALLOW_STORE_UPDATE_DEFAULT = "true";
+    private static final String ALLOW_STORE_EMPTY_RULE_VIOLATION_PROPERTY_NAME = "default.allowStoreEmptyRuleViolation";
+    private static final String ALLOW_STORE_EMPTY_RULE_VIOLATION_DEFAULT = "true";
 
     private final RuleViolationFileNameStrategy ruleViolationFileNameStrategy;
 
     private boolean storeCreationAllowed;
     private boolean storeUpdateAllowed;
+    private boolean storeEmptyRuleViolationAllowed;
     private File storeFolder;
     private FileSyncedProperties storedRules;
 
@@ -103,6 +106,7 @@ public TextFileBasedViolationStore(RuleViolationFileNameStrategy ruleViolationFi
     public void initialize(Properties properties) {
         storeCreationAllowed = Boolean.parseBoolean(properties.getProperty(ALLOW_STORE_CREATION_PROPERTY_NAME, ALLOW_STORE_CREATION_DEFAULT));
         storeUpdateAllowed = Boolean.parseBoolean(properties.getProperty(ALLOW_STORE_UPDATE_PROPERTY_NAME, ALLOW_STORE_UPDATE_DEFAULT));
+        storeEmptyRuleViolationAllowed = Boolean.parseBoolean(properties.getProperty(ALLOW_STORE_EMPTY_RULE_VIOLATION_PROPERTY_NAME, ALLOW_STORE_EMPTY_RULE_VIOLATION_DEFAULT));
         String path = properties.getProperty(STORE_PATH_PROPERTY_NAME, STORE_PATH_DEFAULT);
         storeFolder = new File(path);
         ensureExistence(storeFolder);
@@ -140,6 +144,10 @@ public boolean contains(ArchRule rule) {
     @Override
     public void save(ArchRule rule, List<String> violations) {
         log.trace("Storing evaluated rule '{}' with {} violations: {}", rule.getDescription(), violations.size(), violations);
+        if (violations.isEmpty() && !storeEmptyRuleViolationAllowed) {
+            throw new StoreEmptyException(String.format("Saving empty violations for freezing rule is disabled (enable by configuration %s.%s=true)",
+                    ViolationStoreFactory.FREEZE_STORE_PROPERTY_NAME, ALLOW_STORE_EMPTY_RULE_VIOLATION_PROPERTY_NAME));
+        }
         if (!storeUpdateAllowed) {
             throw new StoreUpdateFailedException(String.format(
                     "Updating frozen violations is disabled (enable by configuration %s.%s=true)",

archunit/src/test/java/com/tngtech/archunit/library/freeze/FreezingArchRuleTest.java

@@ -3,14 +3,7 @@
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Path;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Properties;
-import java.util.Set;
+import java.util.*;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Function;
 
@@ -55,6 +48,7 @@ public class FreezingArchRuleTest {
     private static final String STORE_DEFAULT_PATH_PROPERTY_NAME = "freeze.store.default.path";
     private static final String ALLOW_STORE_CREATION_PROPERTY_NAME = "freeze.store.default.allowStoreCreation";
     private static final String ALLOW_STORE_UPDATE_PROPERTY_NAME = "freeze.store.default.allowStoreUpdate";
+    private static final String ALLOW_STORE_EMPTY_RULE_VIOLATION_PROPERTY_NAME = "freeze.store.default.allowStoreEmptyRuleViolation";
     private static final String LINE_MATCHER_PROPERTY_NAME = "freeze.lineMatcher";
 
     @Rule
@@ -482,6 +476,21 @@ public void can_prevent_default_ViolationStore_from_updating_existing_rules() th
         expectStoreUpdateDisabledException(() -> frozenRule.check(importClasses(getClass())));
     }
 
+    @Test
+    public void warns_when_default_ViolationStore_gets_empty() throws IOException {
+        useTemporaryDefaultStorePath();
+        ArchConfiguration.get().setProperty(ALLOW_STORE_CREATION_PROPERTY_NAME, "true");
+
+        RuleCreator someRule = rule("some description");
+        freeze(someRule.withViolations("remaining", "will be solved").create()).check(importClasses(getClass()));
+
+        ArchConfiguration.get().setProperty(ALLOW_STORE_EMPTY_RULE_VIOLATION_PROPERTY_NAME, "false");
+        FreezingArchRule frozenRule = freeze(someRule.withoutViolations().create());
+        assertThatThrownBy(() -> frozenRule.check(importClasses(getClass())))
+                .isInstanceOf(StoreEmptyException.class)
+                .hasMessageContaining("Saving empty violations for freezing rule is disabled (enable by configuration " + ALLOW_STORE_EMPTY_RULE_VIOLATION_PROPERTY_NAME + "=true)");
+    }
+
     @Test
     public void allows_to_adjust_default_store_file_names_via_delegation() throws IOException {
         // GIVEN