Do not treat Path as Iterable to avoid infinite recursion.

Fixes #1855

src/main/java/org/assertj/core/api/recursive/comparison/DualValue.java

@@ -19,6 +19,7 @@
 import static org.assertj.core.util.Lists.newArrayList;
 import static org.assertj.core.util.Strings.join;
 
+import java.nio.file.Path;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
@@ -166,11 +167,16 @@ public boolean isExpectedFieldAnOrderedCollection() {
   }
 
   public boolean isActualFieldAnIterable() {
-    return actual instanceof Iterable;
+    // ignore Path to be consistent with isExpectedFieldAnIterable
+    return actual instanceof Iterable && !(actual instanceof Path);
   }
 
   public boolean isExpectedFieldAnIterable() {
-    return expected instanceof Iterable;
+    // Don't consider Path as an Iterable as recursively comparing them leads to a stack overflow, here's why:
+    // Iterable are compared element by element recursively
+    // Ex: /tmp/foo.txt path has /tmp as its first element
+    // so /tmp is going to be compared recursively but /tmp first element is itself leading to an infinite recursion
+    return expected instanceof Iterable && !(expected instanceof Path);
   }
 
   private static boolean isAnOrderedCollection(Object value) {

src/test/java/org/assertj/core/api/recursive/comparison/DualValue_iterableValues_Test.java

@@ -19,6 +19,7 @@
 import static org.assertj.core.util.Sets.newLinkedHashSet;
 import static org.assertj.core.util.Sets.newTreeSet;
 
+import java.nio.file.Paths;
 import java.util.List;
 import java.util.stream.Stream;
 
@@ -130,7 +131,8 @@ public void isExpectedFieldAnIterable_should_return_false_when_expected_is_not_a
   }
 
   static Stream<Object> nonIterables() {
-    return Stream.of(123, "abc", array("a", "b"));
+    // even though Path is an iterable, it must not be considered as such
+    return Stream.of(123, "abc", array("a", "b"), Paths.get("/tmp"));
   }
 
 }

src/test/java/org/assertj/core/api/recursive/comparison/RecursiveComparisonAssert_isEqualTo_Test.java

@@ -21,9 +21,12 @@
 import static org.assertj.core.error.ShouldNotBeNull.shouldNotBeNull;
 import static org.assertj.core.test.AlwaysEqualComparator.ALWAY_EQUALS_STRING;
 import static org.assertj.core.util.Lists.list;
+import static org.junit.jupiter.api.condition.OS.WINDOWS;
 import static org.junit.jupiter.params.provider.Arguments.arguments;
 import static org.mockito.Mockito.verify;
 
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.sql.Timestamp;
 import java.util.Date;
 import java.util.stream.Stream;
@@ -36,6 +39,7 @@
 import org.assertj.core.internal.objects.data.Person;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.DisabledOnOs;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
@@ -335,7 +339,30 @@ static class LightString {
     public LightString(String value) {
       this.color = value;
     }
+  }
+
+  @Test
+  @DisabledOnOs(WINDOWS)
+  public void should_not_treat_Path_as_Iterable_to_avoid_infinite_recursion() {
+    final Container container1 = new Container("/tmp/example");
+    final Container container2 = new Container("/tmp/example");
+
+    assertThat(container1).usingRecursiveComparison()
+                          .isEqualTo(container2)
+                          .ignoringAllOverriddenEquals()
+                          .isEqualTo(container2);
+  }
 
+  public static class Container {
+    private Path path;
+
+    public Container(String path) {
+      this.path = Paths.get(path);
+    }
+
+    public Path getPath() {
+      return path;
+    }
   }
 
 }