fix(id_generation): unique ID fallback for unpickleable invocations

tests/unit/mazepa/test_id_generation.py

@@ -219,3 +219,12 @@ def test_persistence_across_sessions() -> None:
         result = pool.map(_gen_id_calls, range(2))
 
     assert result[0] == result[1]
+
+
+def test_unpickleable_fn(mocker) -> None:
+    # See https://github.com/uqfoundation/dill/issues/147 and possibly
+    # https://github.com/uqfoundation/dill/issues/56
+
+    unpickleable_fn = mocker.MagicMock()
+    # gen_id will return a random UUID in case of pickle errors
+    assert gen_id(unpickleable_fn, [], {}) != gen_id(unpickleable_fn, [], {})

zetta_utils/mazepa/id_generation.py

@@ -42,15 +42,20 @@ def generate_invocation_id(
     prefix: Optional[str] = None,
 ):
     x = xxhash.xxh128()
-    x.update(
-        dill.dumps(
-            (fn, args, kwargs),
-            protocol=dill.DEFAULT_PROTOCOL,
-            byref=False,
-            recurse=True,
-            fmode=dill.FILE_FMODE,
+    try:
+        x.update(
+            dill.dumps(
+                (fn, args, kwargs),
+                protocol=dill.DEFAULT_PROTOCOL,
+                byref=False,
+                recurse=True,
+                fmode=dill.FILE_FMODE,
+            )
         )
-    )
+    except dill.PicklingError as e:
+        logger.warning(f"Failed to pickle {fn} with args {args} and kwargs {kwargs}: {e}")
+        x.update(str(uuid.uuid4()))
+
     if prefix is not None:
         return f"{prefix}-{x.hexdigest()}"
     else: