enhance err_msg, test=develop (#23714)

paddle/fluid/imperative/op_base.h

@@ -42,13 +42,25 @@ class OpBase {
 
   ~OpBase() { VLOG(3) << "Destruct Op: " << Type(); }
 
-  const std::string& Type() const { return op_->Type(); }
+  const std::string& Type() const {
+    return op_ ? op_->Type() : UnknownOpType();
+  }
 
   const framework::AttributeMap& Attrs() const { return attrs_; }
 
-  const framework::OpInfo& Info() const { return op_->Info(); }
+  const framework::OpInfo& Info() const {
+    PADDLE_ENFORCE_NOT_NULL(op_, platform::errors::PreconditionNotMet(
+                                     "OpBase::Info() should be called after "
+                                     "OpBase::SetType() is called"));
+    return op_->Info();
+  }
 
-  const framework::OperatorBase& InnerOp() const { return *op_; }
+  const framework::OperatorBase& InnerOp() const {
+    PADDLE_ENFORCE_NOT_NULL(op_, platform::errors::PreconditionNotMet(
+                                     "OpBase::InnerOp() should be called after "
+                                     "OpBase::SetType() is called"));
+    return *op_;
+  }
 
   void ClearBackwardTrace();
 
@@ -63,7 +75,7 @@ class OpBase {
   void SetType(const std::string& type);
 
   void CheckAttrs() {
-    auto& info = op_->Info();
+    auto& info = Info();
     if (info.Checker() != nullptr) {
       info.Checker()->Check(&attrs_, true);
     }
@@ -150,6 +162,12 @@ class OpBase {
                   const framework::AttributeMap& attrs,
                   const platform::Place& place);
 
+ private:
+  static const std::string& UnknownOpType() {
+    static std::string kUnknownOpType{"unknown"};
+    return kUnknownOpType;
+  }
+
  private:
   NameVarMap<VariableWrapper> ins_;
   NameVarMap<VariableWrapper> outs_;

paddle/fluid/imperative/tests/test_layer.cc

@@ -271,6 +271,15 @@ TEST(test_layer, test_dygraph_infershape_context) {
   ASSERT_EQ(have_z, false);
 }
 
+TEST(test_layer, test_inner_op_not_inited) {
+  OpBase op;
+  std::string kUnknown = "unknown";
+  ASSERT_EQ(op.Type(), kUnknown);
+  ASSERT_THROW(op.Info(), platform::EnforceNotMet);
+  ASSERT_THROW(op.InnerOp(), platform::EnforceNotMet);
+  ASSERT_THROW(op.CheckAttrs(), platform::EnforceNotMet);
+}
+
 }  // namespace imperative
 }  // namespace paddle