Fix threading.Thread target misuse in Alpaca paper trading (Issue #1399)

README.md

@@ -75,7 +75,7 @@ Key contributors include:
 
 - [**Hongyang (Bruce) Yang**](https://www.linkedin.com/in/brucehy/) – research and development on financial reinforcement learning frameworks, market environments, and quantitative trading applications
 - [other contributors…]
-  
+
 ## Overview
 
 FinRL has three layers: market environments, agents, and applications.  For a trading task (on the top), an agent (in the middle) interacts with a market environment (at the bottom), making sequential decisions.

finrl/meta/paper_trading/alpaca.py

@@ -177,7 +177,8 @@ def run(self):
                     qty = abs(int(float(position.qty)))
                     respSO = []
                     tSubmitOrder = threading.Thread(
-                        target=self.submitOrder(qty, position.symbol, orderSide, respSO)
+                        target=self.submitOrder,
+                        args=(qty, position.symbol, orderSide, respSO),
                     )
                     tSubmitOrder.start()
                     threads.append(tSubmitOrder)  # record thread for joining later
@@ -239,9 +240,8 @@ def trade(self):
                 qty = abs(int(sell_num_shares))
                 respSO = []
                 tSubmitOrder = threading.Thread(
-                    target=self.submitOrder(
-                        qty, self.stockUniverse[index], "sell", respSO
-                    )
+                    target=self.submitOrder,
+                    args=(qty, self.stockUniverse[index], "sell", respSO),
                 )
                 tSubmitOrder.start()
                 threads.append(tSubmitOrder)  # record thread for joining later
@@ -266,9 +266,8 @@ def trade(self):
                     qty = abs(int(buy_num_shares))
                 respSO = []
                 tSubmitOrder = threading.Thread(
-                    target=self.submitOrder(
-                        qty, self.stockUniverse[index], "buy", respSO
-                    )
+                    target=self.submitOrder,
+                    args=(qty, self.stockUniverse[index], "buy", respSO),
                 )
                 tSubmitOrder.start()
                 threads.append(tSubmitOrder)  # record thread for joining later
@@ -289,7 +288,8 @@ def trade(self):
                 qty = abs(int(float(position.qty)))
                 respSO = []
                 tSubmitOrder = threading.Thread(
-                    target=self.submitOrder(qty, position.symbol, orderSide, respSO)
+                    target=self.submitOrder,
+                    args=(qty, position.symbol, orderSide, respSO),
                 )
                 tSubmitOrder.start()
                 threads.append(tSubmitOrder)  # record thread for joining later

unit_tests/test_alpaca_threading.py

@@ -0,0 +1,52 @@
+from __future__ import annotations
+
+import ast
+from pathlib import Path
+
+ALPACA_PATH = (
+    Path(__file__).resolve().parents[1]
+    / "finrl"
+    / "meta"
+    / "paper_trading"
+    / "alpaca.py"
+)
+
+
+def _thread_calls(tree: ast.AST) -> list[ast.Call]:
+    calls: list[ast.Call] = []
+    for node in ast.walk(tree):
+        if not isinstance(node, ast.Call):
+            continue
+        func = node.func
+        if isinstance(func, ast.Attribute) and func.attr == "Thread":
+            calls.append(node)
+    return calls
+
+
+def _is_submit_order_attr(node: ast.AST) -> bool:
+    return isinstance(node, ast.Attribute) and node.attr == "submitOrder"
+
+
+def test_submit_order_thread_target_is_not_called_immediately() -> None:
+    source = ALPACA_PATH.read_text(encoding="utf-8")
+    tree = ast.parse(source)
+
+    thread_calls = _thread_calls(tree)
+    assert thread_calls, "Expected threading.Thread usage in alpaca.py"
+
+    for call in thread_calls:
+        target_kw = next((kw for kw in call.keywords if kw.arg == "target"), None)
+        if target_kw is None:
+            continue
+
+        target = target_kw.value
+
+        # Regression check: ensure submitOrder is not invoked when creating Thread.
+        if isinstance(target, ast.Call) and _is_submit_order_attr(target.func):
+            raise AssertionError(
+                "submitOrder should be passed as target, not called immediately"
+            )
+
+        if _is_submit_order_attr(target):
+            args_kw = next((kw for kw in call.keywords if kw.arg == "args"), None)
+            assert args_kw is not None, "Thread target submitOrder should pass args=..."