Fix hazzer emission of Optional

We were always emitting Optional<T> for accessors, when they should've been behind `_opt`.

We've refactored our previous accessor into `getter` and `getter_opt`. We'll only emit `getter_opt` when we're dealing with optional fields.

PiperOrigin-RevId: 544087591

rust/test/shared/accessors_test.rs

@@ -31,40 +31,57 @@
 /// Tests covering accessors for singular bool, int64, and bytes fields.
 use unittest_proto::proto2_unittest::TestAllTypes;
 
+#[test]
+fn test_default_accessors() {
+    // defaults are from here:
+    // http://google3/third_party/protobuf/unittest.proto section default_*
+    let msg = TestAllTypes::new();
+    assert_eq!(msg.default_int32(), 41);
+    assert_eq!(msg.default_int64(), 42);
+    assert_eq!(msg.default_bool(), true);
+}
+
 #[test]
 fn test_optional_int32_accessors() {
     let mut msg = TestAllTypes::new();
-    assert_eq!(msg.optional_int32(), None);
+    assert_eq!(msg.optional_int32_opt(), None);
+    assert_eq!(msg.optional_int32(), 0);
 
     msg.optional_int32_set(Some(1));
-    assert_eq!(msg.optional_int32(), Some(1));
+    assert_eq!(msg.optional_int32_opt(), Some(1));
+    assert_eq!(msg.optional_int32(), 1);
 
     msg.optional_int32_set(None);
-    assert_eq!(msg.optional_int32(), None);
+    assert_eq!(msg.optional_int32_opt(), None);
+
+    assert_eq!(msg.optional_int32(), 0);
 }
 
 #[test]
 fn test_optional_int64_accessors() {
     let mut msg = TestAllTypes::new();
-    assert_eq!(msg.optional_int64(), None);
+    assert_eq!(msg.optional_int64_opt(), None);
+    assert_eq!(msg.optional_int64(), 0);
 
     msg.optional_int64_set(Some(42));
-    assert_eq!(msg.optional_int64(), Some(42));
+    assert_eq!(msg.optional_int64_opt(), Some(42));
+    assert_eq!(msg.optional_int64(), 42);
 
     msg.optional_int64_set(None);
-    assert_eq!(msg.optional_int64(), None);
+    assert_eq!(msg.optional_int64_opt(), None);
+    assert_eq!(msg.optional_int64(), 0);
 }
 
 #[test]
 fn test_optional_bool_accessors() {
     let mut msg = TestAllTypes::new();
-    assert_eq!(msg.optional_bool(), None);
+    assert_eq!(msg.optional_bool_opt(), None);
 
     msg.optional_bool_set(Some(true));
-    assert_eq!(msg.optional_bool(), Some(true));
+    assert_eq!(msg.optional_bool_opt(), Some(true));
 
     msg.optional_bool_set(None);
-    assert_eq!(msg.optional_bool(), None);
+    assert_eq!(msg.optional_bool_opt(), None);
 }
 
 #[test]

src/google/protobuf/compiler/rust/accessors/singular_scalar.cc

@@ -52,17 +52,34 @@ class SingularScalar final : public AccessorGenerator {
             {"field", field.desc().name()},
             {"Scalar", PrimitiveRsTypeName(field)},
             {"hazzer_thunk", Thunk(field, "has")},
+            {"getter",
+             [&] {
+               field.Emit({}, R"rs(
+                  pub fn r#$field$(&self) -> $Scalar$ {
+                    unsafe { $getter_thunk$(self.msg) }
+                  }
+                )rs");
+             }},
+            {"getter_opt",
+             [&] {
+               if (!field.desc().is_optional()) return;
+               field.Emit({}, R"rs(
+                  pub fn r#$field$_opt(&self) -> Option<$Scalar$> {
+                    if !unsafe { $hazzer_thunk$(self.msg) } {
+                      return None;
+                    }
+                    Some(unsafe { $getter_thunk$(self.msg) })
+                  }
+                  )rs");
+             }},
             {"getter_thunk", Thunk(field, "get")},
             {"setter_thunk", Thunk(field, "set")},
             {"clearer_thunk", Thunk(field, "clear")},
         },
         R"rs(
-          pub fn r#$field$(&self) -> Option<$Scalar$> {
-            if !unsafe { $hazzer_thunk$(self.msg) } {
-              return None;
-            }
-            Some(unsafe { $getter_thunk$(self.msg) })
-          }
+          $getter$
+          $getter_opt$
+
           pub fn $field$_set(&mut self, val: Option<$Scalar$>) {
             match val {
               Some(val) => unsafe { $setter_thunk$(self.msg, val) },