(tvm-ffi) branch main updated: fix: handle empty metadata in get_global_func_metadata (#417)

[junrushao]

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junrushao pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/tvm-ffi.git


The following commit(s) were added to refs/heads/main by this push:
     new 668ce83  fix: handle empty metadata in get_global_func_metadata (#417)
668ce83 is described below

commit 668ce835939ff60a99c7d982266cf4bdc90ca35b
Author: Guan-Ming (Wesley) Chiu <105915352+guan404m...@users.noreply.github.com>
AuthorDate: Tue Jan 27 06:09:27 2026 +0800

    fix: handle empty metadata in get_global_func_metadata (#417)
    
    ## Related Issue
    
    Fixes #208
    
    ## Why
    
    Python-registered global functions without metadata cause
    JSONDecodeError when get_global_func_metadata() is called because the
    FFI returns an empty string which json.loads() cannot parse.
    
    ## How
    
    - Check for empty metadata string before JSON parsing
    - Return empty dict for functions without metadata
    - Add regression test for Python functions without metadata
---
 python/tvm_ffi/registry.py    |  3 ++-
 tests/python/test_metadata.py | 12 +++++++++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/python/tvm_ffi/registry.py b/python/tvm_ffi/registry.py
index 5b484cd..9ea8e2c 100644
--- a/python/tvm_ffi/registry.py
+++ b/python/tvm_ffi/registry.py
@@ -275,7 +275,8 @@ def get_global_func_metadata(name: str) -> dict[str, Any]:
         Register a Python callable as a global FFI function.
 
     """
-    return json.loads(get_global_func("ffi.GetGlobalFuncMetadata")(name) or 
"{}")
+    metadata_json = get_global_func("ffi.GetGlobalFuncMetadata")(name)
+    return json.loads(metadata_json) if metadata_json else {}
 
 
 def init_ffi_api(namespace: str, target_module_name: str | None = None) -> 
None:
diff --git a/tests/python/test_metadata.py b/tests/python/test_metadata.py
index 116afd3..4d91462 100644
--- a/tests/python/test_metadata.py
+++ b/tests/python/test_metadata.py
@@ -17,7 +17,7 @@
 from typing import Any
 
 import pytest
-from tvm_ffi import get_global_func_metadata
+from tvm_ffi import get_global_func_metadata, register_global_func, 
remove_global_func
 from tvm_ffi.core import TypeInfo, TypeSchema, _lookup_type_attr
 from tvm_ffi.testing import _SchemaAllTypes
 
@@ -163,6 +163,16 @@ def test_metadata_global_func() -> None:
     assert metadata["str_attr"] == "hello"
 
 
+def test_metadata_empty_for_python_func() -> None:
+    @register_global_func("test.python_func_no_metadata")
+    def simple_func(x: int) -> int:
+        return x + 1
+
+    metadata = get_global_func_metadata("test.python_func_no_metadata")
+    assert metadata == {}
+    remove_global_func("test.python_func_no_metadata")
+
+
 def test_metadata_field() -> None:
     type_info: TypeInfo = getattr(_SchemaAllTypes, "__tvm_ffi_type_info__")
     for field in type_info.fields: