Validate that select expression specifies an operand in FlatExprBuilder.

PiperOrigin-RevId: 742358622

Author: jnthntatum

eval/compiler/flat_expr_builder.cc

@@ -840,7 +840,14 @@ class FlatExprVisitor : public cel::AstVisitor {
     }
     if (!ValidateOrError(
             !select_expr.field().empty(),
-            "Invalid expression: select 'field' must not be empty")) {
+            "invalid expression: select 'field' must not be empty")) {
+      return;
+    }
+    if (!ValidateOrError(
+            select_expr.has_operand() &&
+                select_expr.operand().kind_case() !=
+                    cel::ExprKindCase::kUnspecifiedExpr,
+            "invalid expression: select must specify an operand")) {
       return;
     }
 

eval/compiler/flat_expr_builder_test.cc

@@ -467,6 +467,23 @@ TEST(FlatExprBuilderTest, SelectExprUnsetField) {
                        HasSubstr("'field' must not be empty")));
 }
 
+TEST(FlatExprBuilderTest, SelectExprUnsetOperand) {
+  Expr expr;
+  SourceInfo source_info;
+  // An empty ident without the name set should error.
+  google::protobuf::TextFormat::ParseFromString(R"(select_expr{
+    field: 'field'
+    operand { id: 1 }
+    })",
+                                      &expr);
+
+  CelExpressionBuilderFlatImpl builder(NewTestingRuntimeEnv());
+  ASSERT_THAT(RegisterBuiltinFunctions(builder.GetRegistry()), IsOk());
+  EXPECT_THAT(builder.CreateExpression(&expr, &source_info).status(),
+              StatusIs(absl::StatusCode::kInvalidArgument,
+                       HasSubstr("must specify an operand")));
+}
+
 TEST(FlatExprBuilderTest, ComprehensionExprUnsetAccuVar) {
   Expr expr;
   SourceInfo source_info;

eval/eval/BUILD

@@ -203,11 +203,9 @@ cc_library(
         "//common:casting",
         "//common:expr",
         "//common:kind",
-        "//common:native_type",
         "//common:value",
         "//common:value_kind",
         "//eval/internal:errors",
-        "//internal:casts",
         "//internal:number",
         "//internal:status_macros",
         "//runtime/internal:errors",
@@ -312,11 +310,9 @@ cc_library(
         ":evaluator_core",
         ":expression_step_base",
         "//common:expr",
-        "//common:native_type",
         "//common:value",
         "//common:value_kind",
         "//eval/internal:errors",
-        "//internal:casts",
         "//internal:status_macros",
         "//runtime:runtime_options",
         "@com_google_absl//absl/base:nullability",