From 6f09b0ebd152f3bb0e195fa714dbdaa92e560b4c Mon Sep 17 00:00:00 2001
From: Megvii Engine Team <megengine@megvii.com>
Date: Wed, 24 May 2023 13:22:00 +0800
Subject: [PATCH] chore(trace): add more error message for tensor invalid

GitOrigin-RevId: 762334218bb7e52c4be4c8eb66319df6679c4b27
---
 imperative/python/src/tensor.cpp | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/imperative/python/src/tensor.cpp b/imperative/python/src/tensor.cpp
index a93dc43d7..887dbd134 100644
--- a/imperative/python/src/tensor.cpp
+++ b/imperative/python/src/tensor.cpp
@@ -672,7 +672,17 @@ PyObject* TensorWrapper::format() {
 PyObject* TensorWrapper::numpy() {
     auto hv = m_tensor->numpy();
     if (!hv) {
-        PyErr_SetString(PyExc_ValueError, "tensor invalid");
+        if (TransformationManager::get_instance()
+                    .segments[TransformationManager::Segment::Eval]
+                    .size() > 1) {
+            PyErr_SetString(
+                    PyExc_ValueError,
+                    "tensor invalid, can not infer value of this tensor under "
+                    "trace(symbolic=True). You can try to use trace(symbolic=False) to "
+                    "avoid this issue.");
+        } else {
+            PyErr_SetString(PyExc_ValueError, "tensor invalid");
+        }
         return nullptr;
     }
     auto arr = py::reinterpret_steal<py::array>(
-- 
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