From a7b84d5113707ad467684b76ea2ec636e9a4859f Mon Sep 17 00:00:00 2001
From: Michael Gschwind <mikekg@fb.com>
Date: Thu, 3 Sep 2020 09:55:10 -0700
Subject: [PATCH] Prevent from changing the interface specification once set.

Summary: Prevent from changing the interface specification once set.

fbshipit-source-id: 123600ed4f2bf7148d46c8e3cf6dfe0d34908546
---
 pytext/torchscript/module.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pytext/torchscript/module.py b/pytext/torchscript/module.py
index a431c8d21..bcc98a067 100644
--- a/pytext/torchscript/module.py
+++ b/pytext/torchscript/module.py
@@ -150,6 +150,8 @@ def inference_interface(self, argument_type: str):
         # LANGUAGES = 3
         # DENSE_FEAT = 4
 
+        if (sel.argno != -1):
+            raise RuntimeError("Cannot change argument type.")
         if argument_type == "texts":
             self.argno = TEXTS
         else: