make FuzzyViolationLineMatcher ignore hint suffixes

The hint messages added for synthetic/anonymous class violations could break
existing frozen violation stores, since FuzzyViolationLineMatcher would treat
violations with hints as different from violations without hints.

This change makes FuzzyViolationLineMatcher ignore hint suffixes (text following
line separator + line separator + "Hint:") when comparing violations, similar to
how it already ignores line numbers and anonymous class numbers.

Resolves: #1509
Signed-off-by: chadongmin <cdm2883@naver.com>

Author: chadongmin

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

@@ -43,19 +43,23 @@ private static ViolationLineMatcher createInstance(String lineMatcherClassName)
     }
 
     /**
-     * ignores numbers that are potentially line numbers (digits following a ':' and preceding a ')')
+     * Ignores numbers that are potentially line numbers (digits following a ':' and preceding a ')')
      * or compiler-generated numbers of anonymous classes or lambda expressions (digits following a '$').
+     * Also ignores hint suffixes (text following line separator + line separator + "Hint:") that provide
+     * additional guidance but are not part of the core violation message.
      */
     private static class FuzzyViolationLineMatcher implements ViolationLineMatcher {
+        private static final String HINT_MARKER = System.lineSeparator() + System.lineSeparator() + "Hint:";
+
         @Override
         public boolean matches(String str1, String str2) {
             // Compare relevant substrings, in a more performant way than a regex solution like this:
             //
             // normalize = str -> str.replaceAll(":\\d+\\)", ":0)").replaceAll("\\$\\d+", "\\$0");
             // return normalize.apply(str1).equals(normalize.apply(str2));
 
-            RelevantPartIterator relevantPart1 = new RelevantPartIterator(str1);
-            RelevantPartIterator relevantPart2 = new RelevantPartIterator(str2);
+            RelevantPartIterator relevantPart1 = new RelevantPartIterator(removeHintSuffix(str1));
+            RelevantPartIterator relevantPart2 = new RelevantPartIterator(removeHintSuffix(str2));
             while (relevantPart1.hasNext() && relevantPart2.hasNext()) {
                 if (!relevantPart1.next().equals(relevantPart2.next())) {
                     return false;
@@ -64,6 +68,11 @@ public boolean matches(String str1, String str2) {
             return !relevantPart1.hasNext() && !relevantPart2.hasNext();
         }
 
+        private static String removeHintSuffix(String str) {
+            int hintIndex = str.indexOf(HINT_MARKER);
+            return hintIndex >= 0 ? str.substring(0, hintIndex) : str;
+        }
+
         static class RelevantPartIterator {
             private final String str;
             private final int length;

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

@@ -54,4 +54,39 @@ public void default_matcher(String str1, String str2, boolean expected) {
                 .as(String.format("'%s' matches '%s'", str1, str2))
                 .isEqualTo(expected);
     }
+
+    @Test
+    public void default_matcher_ignores_hint_suffix() {
+        ViolationLineMatcher defaultMatcher = ViolationLineMatcherFactory.create();
+
+        String baseViolation = "Class <com.example.MyClass$1> does not have simple name ending with 'Service' in (MyClass.java:42)";
+        String hintSuffix = System.lineSeparator() + System.lineSeparator() +
+                "Hint: The failing class appears to be a synthetic or anonymous class " +
+                "generated by the compiler (e.g., from lambdas, switch expressions, or inner classes).";
+        String violationWithHint = baseViolation + hintSuffix;
+
+        assertThat(defaultMatcher.matches(baseViolation, violationWithHint))
+                .as("violation without hint should match same violation with hint")
+                .isTrue();
+        assertThat(defaultMatcher.matches(violationWithHint, baseViolation))
+                .as("violation with hint should match same violation without hint")
+                .isTrue();
+        assertThat(defaultMatcher.matches(violationWithHint, violationWithHint))
+                .as("violation with hint should match itself")
+                .isTrue();
+    }
+
+    @Test
+    public void default_matcher_ignores_hint_suffix_with_different_line_numbers() {
+        ViolationLineMatcher defaultMatcher = ViolationLineMatcherFactory.create();
+
+        String violation1 = "Class <com.example.MyClass$1> does not have simple name ending with 'Service' in (MyClass.java:42)";
+        String violation2WithHint = "Class <com.example.MyClass$2> does not have simple name ending with 'Service' in (MyClass.java:100)" +
+                System.lineSeparator() + System.lineSeparator() +
+                "Hint: The failing class appears to be a synthetic or anonymous class.";
+
+        assertThat(defaultMatcher.matches(violation1, violation2WithHint))
+                .as("violations with different line numbers and anonymous class numbers should match even with hint")
+                .isTrue();
+    }
 }