Ignore static methods when finding property accessors. Fixes #1458

Previously, when looking for property accessors, Introspection would consider
a static method with a name in the required form as being an accessor for a
property. Where such a static method existed, this was likely to result in the
wrong value being considered as the static method is unlikely to return the
correct value for an instance's property.

This commit updates Introspection so that static methods are ignored when
looking for property accessors.

src/main/java/org/assertj/core/util/introspection/Introspection.java

@@ -34,7 +34,7 @@ public final class Introspection {
 
   /**
    * Returns the getter {@link Method} for a property matching the given name in the given object.
-   * 
+   *
    * @param propertyName the given property name.
    * @param target the given object.
    * @return the getter {@code Method} for a property matching the given name in the given object.
@@ -77,14 +77,19 @@ private static Method findGetter(String propertyName, Object target) {
     String capitalized = propertyName.substring(0, 1).toUpperCase(ENGLISH) + propertyName.substring(1);
     // try to find getProperty
     Method getter = findMethod("get" + capitalized, target);
-    if (getter != null) return getter;
+    if (isValidGetter(getter)) return getter;
     if (bareNamePropertyMethods) {
       // try to find bare name property
       getter = findMethod(propertyName, target);
-      if (getter != null) return getter;
+      if (isValidGetter(getter)) return getter;
     }
     // try to find isProperty for boolean properties
-    return findMethod("is" + capitalized, target);
+    Method isAccessor = findMethod("is" + capitalized, target);
+    return isValidGetter(isAccessor) ? isAccessor : null;
+  }
+
+  private static boolean isValidGetter(Method method) {
+    return method != null && !Modifier.isStatic(method.getModifiers());
   }
 
   private static Method findMethod(String name, Object target) {

src/test/java/org/assertj/core/util/introspection/PropertyOrFieldSupport_getValueOf_Test.java

@@ -112,17 +112,20 @@ public void should_throw_error_when_no_property_nor_public_field_match_given_nam
 
   @Test
   public void should_throw_exception_when_given_property_or_field_name_is_null() {
-    assertThatIllegalArgumentException().isThrownBy(() -> propertyOrFieldSupport.getValueOf(null, yoda)).withMessage("The name of the property/field to read should not be null");
+    assertThatIllegalArgumentException().isThrownBy(() -> propertyOrFieldSupport.getValueOf(null, yoda))
+                                        .withMessage("The name of the property/field to read should not be null");
   }
 
   @Test
   public void should_throw_exception_when_given_name_is_empty() {
-    assertThatIllegalArgumentException().isThrownBy(() -> propertyOrFieldSupport.getValueOf("", yoda)).withMessage("The name of the property/field to read should not be empty");
+    assertThatIllegalArgumentException().isThrownBy(() -> propertyOrFieldSupport.getValueOf("", yoda))
+                                        .withMessage("The name of the property/field to read should not be empty");
   }
 
   @Test
   public void should_throw_exception_if_property_cannot_be_extracted_due_to_runtime_exception_during_property_access() {
-    assertThatExceptionOfType(IntrospectionError.class).isThrownBy(() -> propertyOrFieldSupport.getValueOf("adult", brokenEmployee()));
+    assertThatExceptionOfType(IntrospectionError.class).isThrownBy(() -> propertyOrFieldSupport.getValueOf("adult",
+                                                                                                           brokenEmployee()));
   }
 
   @Test
@@ -151,6 +154,27 @@ public void should_extract_single_value_from_maps_by_key() {
     assertThat(maps).extracting("bad key").containsExactly(null, null);
   }
 
+  @Test
+  public void should_extract_field_value_if_only_static_getter_matches_name() {
+    Object value = propertyOrFieldSupport.getValueOf("city", new StaticPropertyEmployee());
+
+    assertThat(value).isEqualTo("New York");
+  }
+
+  @Test
+  public void should_extract_field_value_if_only_static_is_method_matches_name() {
+    Object value = propertyOrFieldSupport.getValueOf("tall", new StaticBooleanPropertyEmployee());
+
+    assertThat(value).isEqualTo(false);
+  }
+
+  @Test
+  public void should_extract_field_value_if_only_static_bare_method_matches_name() {
+    Object value = propertyOrFieldSupport.getValueOf("city", new StaticBarePropertyEmployee());
+
+    assertThat(value).isEqualTo("New York");
+  }
+
   private Employee employeeWithBrokenName(String name) {
     return new Employee(1L, new Name(name), 0) {
       @Override
@@ -178,4 +202,24 @@ public boolean isAdult() {
     };
   }
 
+  static class StaticPropertyEmployee extends Employee {
+    public static String getCity() {
+      return "London";
+    }
+  }
+
+  static class StaticBarePropertyEmployee extends Employee {
+    public static String city() {
+      return "London";
+    }
+  }
+
+  static class StaticBooleanPropertyEmployee extends Employee {
+    boolean tall = false;
+
+    public static boolean isTall() {
+      return true;
+    }
+  }
+
 }