feat(rust): support thread safe Arc<dyn Any + Send + Sync> type (#3736)

## Why?



## What does this PR do?



## Related issues

Closes #3732

## AI Contribution Checklist



- [ ] Substantial AI assistance was used in this PR: `yes` / `no`
- [ ] If `yes`, I included a completed [AI Contribution
Checklist](https://github.com/apache/fory/blob/main/AI_POLICY.md#9-contributor-checklist-for-ai-assisted-prs)
in this PR description and the required `AI Usage Disclosure`.
- [ ] If `yes`, my PR description includes the required `ai_review`
summary and screenshot evidence of the final clean AI review results
from both fresh reviewers on the current PR diff or current HEAD after
the latest code changes.



## Does this PR introduce any user-facing change?



- [ ] Does this PR introduce any public API change?
- [ ] Does this PR introduce any binary protocol compatibility change?

## Benchmark

Author: chaokunyang

compiler/extension/fory_options.proto

@@ -179,10 +179,11 @@ message ForyFieldOptions {
   optional bool weak_ref = 4;
 
   // Generate thread-safe Rust pointer carriers for ref fields.
-  // When true, Rust codegen uses Arc/ArcWeak instead of Rc/RcWeak.
+  // Rust codegen uses Arc/ArcWeak by default. Set this to false to generate
+  // Rc/RcWeak for ref fields that must stay single-threaded.
   // This does not change the wire format and does not make the referenced
   // value itself thread-safe.
-  // Default: false
+  // Default: true
   optional bool thread_safe_pointer = 5;
 }
 

compiler/fory_compiler/generators/rust.py

@@ -34,6 +34,7 @@
     ArrayType,
     MapType,
     Schema,
+    thread_safe_pointer_enabled,
 )
 from fory_compiler.ir.types import PrimitiveKind
 
@@ -43,6 +44,7 @@ class RustGenerator(BaseGenerator):
 
     language_name = "rust"
     file_extension = ".rs"
+    RUST_ANY_TYPE = "::std::sync::Arc<dyn ::std::any::Any + Send + Sync>"
 
     # Mapping from FDL primitive types to Rust types
     PRIMITIVE_MAP = {
@@ -62,7 +64,7 @@ class RustGenerator(BaseGenerator):
         PrimitiveKind.STRING: "::std::string::String",
         PrimitiveKind.BYTES: "::std::vec::Vec<u8>",
         PrimitiveKind.DECIMAL: "::fory::Decimal",
-        PrimitiveKind.ANY: "::std::boxed::Box<dyn ::std::any::Any>",
+        PrimitiveKind.ANY: RUST_ANY_TYPE,
     }
 
     FORY_TEMPORAL_MAP = {
@@ -1012,12 +1014,12 @@ def generate_type(
         element_optional: bool = False,
         element_ref: bool = False,
         parent_stack: Optional[List[Message]] = None,
-        pointer_type: str = "::std::rc::Rc",
+        pointer_type: str = "::std::sync::Arc",
     ) -> str:
         """Generate Rust type string."""
         if isinstance(field_type, PrimitiveType):
             if field_type.kind == PrimitiveKind.ANY:
-                return "::std::boxed::Box<dyn ::std::any::Any>"
+                return self.RUST_ANY_TYPE
             base_type = self.primitive_type_name(field_type.kind)
             if nullable:
                 return f"::std::option::Option<{base_type}>"
@@ -1152,7 +1154,7 @@ def get_field_pointer_type(self, field: Field) -> str:
 
     def get_pointer_type(self, ref_options: dict, weak_ref: bool = False) -> str:
         """Determine pointer type for ref tracking based on field options."""
-        if ref_options.get("thread_safe_pointer") is True:
+        if thread_safe_pointer_enabled(ref_options):
             return "::fory::ArcWeak" if weak_ref else "::std::sync::Arc"
         return "::fory::RcWeak" if weak_ref else "::std::rc::Rc"
 

compiler/fory_compiler/ir/ast.py

@@ -22,6 +22,13 @@
 
 from fory_compiler.ir.types import PrimitiveKind
 
+THREAD_SAFE_POINTER_DEFAULT = True
+
+
+def thread_safe_pointer_enabled(ref_options: dict) -> bool:
+    """Return the effective Rust pointer-carrier default for ref options."""
+    return ref_options.get("thread_safe_pointer", THREAD_SAFE_POINTER_DEFAULT) is True
+
 
 @dataclass(frozen=True)
 class SourceLocation:

compiler/fory_compiler/tests/test_generated_code.py

@@ -216,8 +216,8 @@ def test_rust_nested_container_ref_uses_correct_pointer_type():
             }
 
             message Request {
-                list<list<ref(thread_safe=true) Node>> groups = 1;
-                map<string, map<string, ref(thread_safe=true) Node>> nodes = 2;
+                list<list<ref Node>> groups = 1;
+                map<string, map<string, ref Node>> nodes = 2;
             }
             """
         )
@@ -497,7 +497,7 @@ def test_generated_code_map_types_equivalent():
     assert "SharedWeak<MapValue>" in cpp_output
 
 
-def test_rust_generated_ref_pointer_default_and_thread_safe_option():
+def test_rust_generated_ref_pointer_default_and_opt_out():
     schema = parse_fdl(
         dedent(
             """
@@ -509,25 +509,24 @@ def test_rust_generated_ref_pointer_default_and_thread_safe_option():
 
             message Holder {
                 ref Node default_ref = 1;
-                ref(thread_safe=true) Node thread_safe_ref = 2;
+                ref(thread_safe=false) Node rc_ref = 2;
                 ref(weak=true) Node default_weak_ref = 3;
-                ref(weak=true, thread_safe=true) Node thread_safe_weak_ref = 4;
+                ref(weak=true, thread_safe=false) Node rc_weak_ref = 4;
                 list<ref Node> default_ref_list = 5;
-                list<ref(thread_safe=true) Node> thread_safe_ref_list = 6;
+                list<ref(thread_safe=false) Node> rc_ref_list = 6;
             }
             """
         )
     )
     rust_output = render_files(generate_files(schema, RustGenerator))
-    assert "pub default_ref: ::std::rc::Rc<Node>," in rust_output
-    assert "pub thread_safe_ref: ::std::sync::Arc<Node>," in rust_output
-    assert "pub default_weak_ref: ::fory::RcWeak<Node>," in rust_output
-    assert "pub thread_safe_weak_ref: ::fory::ArcWeak<Node>," in rust_output
-    assert "pub default_ref_list: ::std::vec::Vec<::std::rc::Rc<Node>>," in rust_output
+    assert "pub default_ref: ::std::sync::Arc<Node>," in rust_output
+    assert "pub rc_ref: ::std::rc::Rc<Node>," in rust_output
+    assert "pub default_weak_ref: ::fory::ArcWeak<Node>," in rust_output
+    assert "pub rc_weak_ref: ::fory::RcWeak<Node>," in rust_output
     assert (
-        "pub thread_safe_ref_list: ::std::vec::Vec<::std::sync::Arc<Node>>,"
-        in rust_output
+        "pub default_ref_list: ::std::vec::Vec<::std::sync::Arc<Node>>," in rust_output
     )
+    assert "pub rc_ref_list: ::std::vec::Vec<::std::rc::Rc<Node>>," in rust_output
 
 
 def test_generated_code_nested_messages_equivalent():
@@ -779,7 +778,7 @@ def test_generated_code_tree_ref_options_equivalent():
     assert_all_languages_equal(schemas)
 
     rust_output = render_files(generate_files(schemas["fdl"], RustGenerator))
-    assert "RcWeak<TreeNode>" in rust_output
+    assert "ArcWeak<TreeNode>" in rust_output
     assert "#[derive(::fory::ForyStruct, Clone, PartialEq, Eq, Default)]" in rust_output
 
     cpp_output = render_files(generate_files(schemas["fdl"], CppGenerator))
@@ -1153,8 +1152,11 @@ def test_rust_generated_code_uses_absolute_paths():
         "pub labels: ::std::collections::HashMap<::std::string::String, ::std::string::String>,"
         in rust_output
     )
-    assert "pub payload: ::std::boxed::Box<dyn ::std::any::Any>," in rust_output
-    assert "pub parent: ::fory::RcWeak<String>," in rust_output
+    assert (
+        "pub payload: ::std::sync::Arc<dyn ::std::any::Any + Send + Sync>,"
+        in rust_output
+    )
+    assert "pub parent: ::fory::ArcWeak<String>," in rust_output
     assert "pub fn register_types(fory: &mut ::fory::Fory)" in rust_output
     assert "static FORY: ::std::sync::OnceLock<::fory::Fory>" in rust_output
 

compiler/fory_compiler/tests/test_weak_ref.py

@@ -122,7 +122,7 @@ def test_weak_ref_requires_repeated_ref():
     )
 
 
-def test_list_and_map_ref_options_with_thread_safe():
+def test_list_and_map_ref_options_preserve_explicit_opt_out():
     source = """
     message Foo {
         int32 id = 1;
@@ -134,8 +134,8 @@ def test_list_and_map_ref_options_with_thread_safe():
 
     message Holder {
         list<ref Foo> foos = 1;
-        list<ref(weak=true, thread_safe=true) Bar> bars = 2;
-        map<Foo, ref(weak=true, thread_safe=true) Bar> bar_map = 3;
+        list<ref(weak=true, thread_safe=false) Bar> bars = 2;
+        map<Foo, ref(weak=true, thread_safe=false) Bar> bar_map = 3;
     }
     """
     schema = parse_schema(source)
@@ -152,8 +152,8 @@ def test_list_and_map_ref_options_with_thread_safe():
 
     assert bars.element_ref is True
     assert bars.element_ref_options.get("weak_ref") is True
-    assert bars.element_ref_options.get("thread_safe_pointer") is True
+    assert bars.element_ref_options.get("thread_safe_pointer") is False
 
     assert bar_map.field_type.value_ref is True
     assert bar_map.field_type.value_ref_options.get("weak_ref") is True
-    assert bar_map.field_type.value_ref_options.get("thread_safe_pointer") is True
+    assert bar_map.field_type.value_ref_options.get("thread_safe_pointer") is False

docs/compiler/flatbuffers-idl.md

@@ -156,20 +156,20 @@ FlatBuffers metadata attributes use `key:value`. For Fory-specific options, use
 
 ### Supported Field Attributes
 
-| FlatBuffers Attribute           | Effect in Fory                                                                   |
-| ------------------------------- | -------------------------------------------------------------------------------- |
-| `fory_ref:true`                 | Enable reference tracking for the field                                          |
-| `fory_nullable:true`            | Mark field optional/nullable                                                     |
-| `fory_weak_ref:true`            | Enable weak reference semantics and implies `ref`                                |
-| `fory_thread_safe_pointer:true` | For ref fields, select Rust `Arc`/`ArcWeak` instead of the default `Rc`/`RcWeak` |
+| FlatBuffers Attribute            | Effect in Fory                                                                   |
+| -------------------------------- | -------------------------------------------------------------------------------- |
+| `fory_ref:true`                  | Enable reference tracking for the field                                          |
+| `fory_nullable:true`             | Mark field optional/nullable                                                     |
+| `fory_weak_ref:true`             | Enable weak reference semantics and implies `ref`                                |
+| `fory_thread_safe_pointer:false` | For ref fields, select Rust `Rc`/`RcWeak` instead of the default `Arc`/`ArcWeak` |
 
 Semantics:
 
 - `fory_weak_ref:true` implies `ref`.
-- `fory_thread_safe_pointer` defaults to `false`, only takes effect when the field
+- `fory_thread_safe_pointer` defaults to `true`, only takes effect when the field
   is ref-tracked, and does not change the wire format.
-- In Rust codegen, `fory_weak_ref:true` uses `RcWeak` by default and switches to
-  `ArcWeak` only when `fory_thread_safe_pointer:true` is also set.
+- In Rust codegen, `fory_weak_ref:true` uses `ArcWeak` by default and switches to
+  `RcWeak` only when `fory_thread_safe_pointer:false` is set.
 - For list fields, `fory_ref:true` applies to list elements.
 
 Example:
@@ -178,7 +178,7 @@ Example:
 table Node {
   parent: Node (fory_weak_ref: true);
   children: [Node] (fory_ref: true);
-  cached: Node (fory_ref: true, fory_thread_safe_pointer: true);
+  local: Node (fory_ref: true, fory_thread_safe_pointer: false);
 }
 ```
 

docs/compiler/protobuf-idl.md

@@ -232,34 +232,35 @@ message TreeNode {
 
 ### Field-Level Options
 
-| Option                       | Type   | Description                                                                 |
-| ---------------------------- | ------ | --------------------------------------------------------------------------- |
-| `(fory).ref`                 | bool   | Enable reference tracking for this field                                    |
-| `(fory).nullable`            | bool   | Treat field as nullable (`optional`)                                        |
-| `(fory).weak_ref`            | bool   | Generate weak pointer semantics (C++/Rust codegen)                          |
-| `(fory).thread_safe_pointer` | bool   | Use Rust `Arc`/`ArcWeak` for ref fields; default `false` uses `Rc`/`RcWeak` |
-| `(fory).deprecated`          | bool   | Mark field as deprecated                                                    |
-| `(fory).type`                | string | Primitive override for tagged 64-bit integer encoding                       |
+| Option                       | Type   | Description                                                                                          |
+| ---------------------------- | ------ | ---------------------------------------------------------------------------------------------------- |
+| `(fory).ref`                 | bool   | Enable reference tracking for this field                                                             |
+| `(fory).nullable`            | bool   | Treat field as nullable (`optional`)                                                                 |
+| `(fory).weak_ref`            | bool   | Generate weak pointer semantics (C++/Rust codegen)                                                   |
+| `(fory).thread_safe_pointer` | bool   | Rust ref carrier selection; default `true` uses `Arc`/`ArcWeak`, explicit `false` uses `Rc`/`RcWeak` |
+| `(fory).deprecated`          | bool   | Mark field as deprecated                                                                             |
+| `(fory).type`                | string | Primitive override for tagged 64-bit integer encoding                                                |
 
 Reference option behavior:
 
 - `weak_ref = true` implies ref tracking.
 - For `repeated` fields, `(fory).ref = true` applies to list elements.
 - For `map<K, V>` fields, `(fory).ref = true` applies to map values.
 - `weak_ref` and `thread_safe_pointer` are codegen hints for C++/Rust.
-- `thread_safe_pointer` defaults to `false`; it changes only the generated Rust
+- `thread_safe_pointer` defaults to `true`; it changes only the generated Rust
   pointer carrier and does not change the wire format.
-- In Rust codegen, `(fory).weak_ref = true` uses `RcWeak` by default and switches
-  to `ArcWeak` only when `(fory).thread_safe_pointer = true`.
+- In Rust codegen, `(fory).weak_ref = true` uses `ArcWeak` by default and
+  switches to `RcWeak` only when `(fory).thread_safe_pointer = false`.
 
 ### Option Examples by Shape
 
 ```protobuf
 message Graph {
-  Node root = 1 [(fory).ref = true, (fory).thread_safe_pointer = true];
+  Node root = 1 [(fory).ref = true];
   repeated Node nodes = 2 [(fory).ref = true];
   map<string, Node> cache = 3 [(fory).ref = true];
   Node parent = 4 [(fory).weak_ref = true];
+  Node local = 5 [(fory).ref = true, (fory).thread_safe_pointer = false];
 }
 ```