fix: JSON deserialization setter case priority (#1831)

* fix: JSON deserialization setter case priority

Fixes the problem of JSON deserialization ignoring the case of setters.
Now case-sensitive setter method matches are considered first.

Fixes: #1830.

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

google-http-client/src/main/java/com/google/api/client/util/FieldInfo.java

@@ -134,12 +134,20 @@ public static FieldInfo of(Field field) {
   }
 
   /** Creates list of setter methods for a field only in declaring class. */
-  private Method[] settersMethodForField(Field field) {
+  private Method[] settersMethodForField(final Field field) {
     List<Method> methods = new ArrayList<>();
+    String fieldSetter = "set" + Ascii.toUpperCase(field.getName().substring(0, 1));
+    if (field.getName().length() > 1) {
+      fieldSetter += field.getName().substring(1);
+    }
     for (Method method : field.getDeclaringClass().getDeclaredMethods()) {
-      if (Ascii.toLowerCase(method.getName()).equals("set" + Ascii.toLowerCase(field.getName()))
-          && method.getParameterTypes().length == 1) {
-        methods.add(method);
+      if (method.getParameterTypes().length == 1) {
+        // add case-sensitive matches first in the list
+        if (method.getName().equals(fieldSetter)) {
+          methods.add(0, method);
+        } else if (Ascii.toLowerCase(method.getName()).equals(Ascii.toLowerCase(fieldSetter))) {
+          methods.add(method);
+        }
       }
     }
     return methods.toArray(new Method[0]);
@@ -216,15 +224,13 @@ public Object getValue(Object obj) {
    * value.
    */
   public void setValue(Object obj, Object value) {
-    if (setters.length > 0) {
-      for (Method method : setters) {
-        if (value == null || method.getParameterTypes()[0].isAssignableFrom(value.getClass())) {
-          try {
-            method.invoke(obj, value);
-            return;
-          } catch (IllegalAccessException | InvocationTargetException e) {
-            // try to set field directly
-          }
+    for (Method method : setters) {
+      if (value == null || method.getParameterTypes()[0].isAssignableFrom(value.getClass())) {
+        try {
+          method.invoke(obj, value);
+          return;
+        } catch (IllegalAccessException | InvocationTargetException e) {
+          // try to set field directly
         }
       }
     }

google-http-client/src/test/java/com/google/api/client/util/FieldInfoTest.java

@@ -14,6 +14,7 @@
 
 package com.google.api.client.util;
 
+import com.google.api.client.json.GenericJson;
 import junit.framework.TestCase;
 
 /**
@@ -49,4 +50,36 @@ public void testEnumValue() {
     assertEquals(E.OTHER_VALUE, FieldInfo.of(E.OTHER_VALUE).<E>enumValue());
     assertEquals(E.NULL, FieldInfo.of(E.NULL).<E>enumValue());
   }
+
+  public static final class Data extends GenericJson {
+    @Key String passcode;
+    @Key String passCode;
+
+    public Data setPasscode(String passcode) {
+      this.passcode = passcode;
+      return this;
+    }
+
+    public Data setPassCode(String passCode) {
+      this.passCode = passCode;
+      return this;
+    }
+  }
+
+  public void testSetValueCaseSensitivityPriority() {
+    Data data = new Data();
+    data.setPasscode("pass1");
+    data.setPassCode("pass2");
+    data.set("passCode", "passX");
+
+    assertEquals(data.passcode, "pass1");
+    assertEquals(data.passCode, "passX");
+
+    data.setPasscode("pass1");
+    data.setPassCode("pass2");
+    data.set("passcode", "passX");
+
+    assertEquals(data.passcode, "passX");
+    assertEquals(data.passCode, "pass2");
+  }
 }