From 8d89614d8aeb42862ce1fc089bad6862749d3df2 Mon Sep 17 00:00:00 2001
From: Umut <umutsahin@protonmail.com>
Date: Thu, 23 Feb 2023 13:44:50 +0100
Subject: [PATCH] feat: raise error if tracers are tried to be converted to
 bool

---
 concrete/numpy/tracing/tracer.py | 6 ++++++
 tests/tracing/test_tracer.py     | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/concrete/numpy/tracing/tracer.py b/concrete/numpy/tracing/tracer.py
index e3ae9f9de..49abb53b1 100644
--- a/concrete/numpy/tracing/tracer.py
+++ b/concrete/numpy/tracing/tracer.py
@@ -175,6 +175,12 @@ class Tracer:
     def __hash__(self) -> int:
         return id(self)
 
+    def __bool__(self) -> bool:
+        # pylint: disable=invalid-bool-returned
+
+        message = "Branching within circuits is not possible"
+        raise RuntimeError(message)
+
     @staticmethod
     def sanitize(value: Any) -> Any:
         """
diff --git a/tests/tracing/test_tracer.py b/tests/tracing/test_tracer.py
index 95f95990f..773742feb 100644
--- a/tests/tracing/test_tracer.py
+++ b/tests/tracing/test_tracer.py
@@ -45,6 +45,12 @@ from concrete.numpy.values import EncryptedTensor
             "`astype` method must be called with a "
             "numpy type for compilation (e.g., value.astype(np.int64))",
         ),
+        pytest.param(
+            lambda x: x + 1 if x else x + x,
+            {"x": EncryptedTensor(UnsignedInteger(7), shape=())},
+            RuntimeError,
+            "Branching within circuits is not possible",
+        ),
     ],
 )
 def test_tracer_bad_trace(function, parameters, expected_error, expected_message):