From 5d4cd1c1918b4f417b9ebb51e5a12b5692bd7384 Mon Sep 17 00:00:00 2001
From: wakonig_k <klaus.wakonig@psi.ch>
Date: Sat, 18 Nov 2023 12:14:17 +0100
Subject: [PATCH] fix: fixed signature serializer for typing.Literal

---
 bec_lib/bec_lib/signature_serializer.py    | 29 ++++++++++++++++------
 bec_lib/tests/test_signature_serializer.py | 25 +++++++++++++++++++
 2 files changed, 47 insertions(+), 7 deletions(-)

diff --git a/bec_lib/bec_lib/signature_serializer.py b/bec_lib/bec_lib/signature_serializer.py
index 6938d161..161b2f5d 100644
--- a/bec_lib/bec_lib/signature_serializer.py
+++ b/bec_lib/bec_lib/signature_serializer.py
@@ -1,9 +1,9 @@
 import builtins
 import inspect
-from typing import Callable, List
+from typing import Any, Callable, List, Literal
 
 
-def dtype_to_str(dtype: type) -> str:
+def serialize_dtype(dtype: type) -> Any:
     """
     Convert a dtype to a string.
 
@@ -13,12 +13,17 @@ def dtype_to_str(dtype: type) -> str:
     Returns:
         str: String representation of the data type
     """
-    return dtype.__name__
+    if hasattr(dtype, "__name__"):
+        return dtype.__name__
+    if hasattr(dtype, "__module__"):
+        if dtype.__module__ == "typing":
+            return {"Literal": dtype.__args__}
+    raise ValueError(f"Unknown dtype {dtype}")
 
 
-def str_to_dtype(dtype: str) -> type:
+def deserialize_dtype(dtype: Any) -> type:
     """
-    Convert a string to a dtype.
+    Convert a serialized dtype to a type.
 
     Args:
         dtype (str): String representation of the data type
@@ -27,7 +32,15 @@ def str_to_dtype(dtype: str) -> type:
         type: Data type
     """
     if dtype == "_empty":
+        # pylint: disable=protected-access
         return inspect._empty
+    if isinstance(dtype, dict):
+        # bodge needed for python 3.8
+        if "Literal" in dtype:
+            literal = Literal["dummy"]
+            literal.__args__ = dtype["Literal"]
+            return literal
+        raise ValueError(f"Unknown dtype {dtype}")
     return builtins.__dict__.get(dtype)
 
 
@@ -47,12 +60,13 @@ def signature_to_dict(func: Callable, include_class_obj=False) -> dict:
     for param_name, param in params.items():
         if not include_class_obj and param_name == "self" or param_name == "cls":
             continue
+        # pylint: disable=protected-access
         out.append(
             {
                 "name": param_name,
                 "kind": param.kind.name,
                 "default": param.default if param.default != inspect._empty else "_empty",
-                "annotation": dtype_to_str(param.annotation),
+                "annotation": serialize_dtype(param.annotation),
             }
         )
     return out
@@ -70,12 +84,13 @@ def dict_to_signature(params: List[dict]) -> inspect.Signature:
     """
     out = []
     for param in params:
+        # pylint: disable=protected-access
         out.append(
             inspect.Parameter(
                 name=param["name"],
                 kind=getattr(inspect.Parameter, param["kind"]),
                 default=param["default"] if param["default"] != "_empty" else inspect._empty,
-                annotation=str_to_dtype(param["annotation"]),
+                annotation=deserialize_dtype(param["annotation"]),
             )
         )
     return inspect.Signature(out)
diff --git a/bec_lib/tests/test_signature_serializer.py b/bec_lib/tests/test_signature_serializer.py
index 86e320be..ebf338a6 100644
--- a/bec_lib/tests/test_signature_serializer.py
+++ b/bec_lib/tests/test_signature_serializer.py
@@ -1,4 +1,5 @@
 import inspect
+import typing
 
 from bec_lib.signature_serializer import dict_to_signature, signature_to_dict
 
@@ -28,3 +29,27 @@ def test_signature_serializer():
 
     sig = dict_to_signature(params)
     assert sig == inspect.signature(test_func)
+
+
+def test_signature_serializer_with_literals():
+    def test_func(a, b: typing.Literal[1, 2, 3] = 1):
+        pass
+
+    params = signature_to_dict(test_func)
+    assert params == [
+        {
+            "name": "a",
+            "kind": "POSITIONAL_OR_KEYWORD",
+            "default": "_empty",
+            "annotation": "_empty",
+        },
+        {
+            "name": "b",
+            "kind": "POSITIONAL_OR_KEYWORD",
+            "default": 1,
+            "annotation": {"Literal": (1, 2, 3)},
+        },
+    ]
+
+    sig = dict_to_signature(params)
+    assert sig == inspect.signature(test_func)