Move Expr to/from proto conversion to common/ast. Similar visibility rules to previous location (all the CEL library components may refer to it, but not CEL users).

Follow up will move the AST conversion code out of extensions.

PiperOrigin-RevId: 736184373

Author: jnthntatum

common/BUILD

@@ -133,9 +133,12 @@ cc_test(
         ":ast_visitor",
         ":expr",
         "//base/ast_internal:ast_impl",
+        "//base/ast_internal:expr",
+        "//common/ast:expr_proto",
         "//extensions/protobuf:ast_converters",
         "//internal:testing",
         "//parser",
+        "@com_google_absl//absl/status:status_matchers",
         "@com_google_cel_spec//proto/cel/expr:syntax_cc_proto",
         "@com_google_protobuf//:protobuf",
     ],

common/ast.h

@@ -30,9 +30,9 @@ class AstImpl;
 // manage lifecycle.
 //
 // Implementations are intentionally opaque to prevent dependencies on the
-// details of the runtime representation. To create an new instance, see the
-// factories in the extensions package (e.g.
-// extensions/protobuf/ast_converters.h).
+// details of the runtime representation. To create a new instance, from a
+// protobuf representation, use the conversion utilities in
+// `extensions/protobuf/ast_converters.h`.
 class Ast {
  public:
   virtual ~Ast() = default;

common/ast/BUILD

@@ -0,0 +1,71 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# Internal AST implementation and utilities
+# These are needed by various parts of the CEL-C++ library, but are not intended for public use at
+# this time.
+package(default_visibility = ["//visibility:public"])
+
+cc_library(
+    name = "constant_proto",
+    srcs = ["constant_proto.cc"],
+    hdrs = ["constant_proto.h"],
+    deps = [
+        "//common:constant",
+        "//internal:proto_time_encoding",
+        "@com_google_absl//absl/base:nullability",
+        "@com_google_absl//absl/functional:overload",
+        "@com_google_absl//absl/status",
+        "@com_google_absl//absl/strings",
+        "@com_google_absl//absl/time",
+        "@com_google_absl//absl/types:variant",
+        "@com_google_cel_spec//proto/cel/expr:syntax_cc_proto",
+        "@com_google_protobuf//:protobuf",
+    ],
+)
+
+cc_library(
+    name = "expr_proto",
+    srcs = ["expr_proto.cc"],
+    hdrs = ["expr_proto.h"],
+    deps = [
+        ":constant_proto",
+        "//common:constant",
+        "//common:expr",
+        "//internal:status_macros",
+        "@com_google_absl//absl/base:core_headers",
+        "@com_google_absl//absl/base:nullability",
+        "@com_google_absl//absl/functional:overload",
+        "@com_google_absl//absl/status",
+        "@com_google_absl//absl/strings",
+        "@com_google_absl//absl/types:variant",
+        "@com_google_cel_spec//proto/cel/expr:syntax_cc_proto",
+        "@com_google_protobuf//:protobuf",
+    ],
+)
+
+cc_test(
+    name = "expr_proto_test",
+    srcs = ["expr_proto_test.cc"],
+    deps = [
+        ":expr_proto",
+        "//common:expr",
+        "//internal:proto_matchers",
+        "//internal:testing",
+        "@com_google_absl//absl/status",
+        "@com_google_absl//absl/status:status_matchers",
+        "@com_google_cel_spec//proto/cel/expr:syntax_cc_proto",
+        "@com_google_protobuf//:protobuf",
+    ],
+)

extensions/protobuf/internal/constant.cc common/ast/constant_proto.ccextensions/protobuf/internal/constant.cc renamed to common/ast/constant_proto.cc

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#include "extensions/protobuf/internal/constant.h"
+#include "common/ast/constant_proto.h"
 
 #include <cstddef>
 #include <cstdint>
@@ -28,7 +28,7 @@
 #include "common/constant.h"
 #include "internal/proto_time_encoding.h"
 
-namespace cel::extensions::protobuf_internal {
+namespace cel::ast_internal {
 
 using ConstantProto = cel::expr::Constant;
 
@@ -120,4 +120,4 @@ absl::Status ConstantFromProto(const ConstantProto& proto, Constant& constant) {
   return absl::OkStatus();
 }
 
-}  // namespace cel::extensions::protobuf_internal
+}  // namespace cel::ast_internal

extensions/protobuf/internal/constant.h common/ast/constant_proto.hextensions/protobuf/internal/constant.h renamed to common/ast/constant_proto.h

@@ -12,15 +12,15 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#ifndef THIRD_PARTY_CEL_CPP_EXTENSIONS_PROTOBUF_INTERNAL_CONSTANT_H_
-#define THIRD_PARTY_CEL_CPP_EXTENSIONS_PROTOBUF_INTERNAL_CONSTANT_H_
+#ifndef THIRD_PARTY_CEL_CPP_COMMON_AST_CONSTANT_PROTO_H_
+#define THIRD_PARTY_CEL_CPP_COMMON_AST_CONSTANT_PROTO_H_
 
 #include "cel/expr/syntax.pb.h"
 #include "absl/base/nullability.h"
 #include "absl/status/status.h"
 #include "common/constant.h"
 
-namespace cel::extensions::protobuf_internal {
+namespace cel::ast_internal {
 
 // `ConstantToProto` converts from native `Constant` to its protocol buffer
 // message equivalent.
@@ -32,6 +32,6 @@ absl::Status ConstantToProto(const Constant& constant,
 absl::Status ConstantFromProto(const cel::expr::Constant& proto,
                                Constant& constant);
 
-}  // namespace cel::extensions::protobuf_internal
+}  // namespace cel::ast_internal
 
-#endif  // THIRD_PARTY_CEL_CPP_EXTENSIONS_PROTOBUF_INTERNAL_CONSTANT_H_
+#endif  // THIRD_PARTY_CEL_CPP_COMMON_AST_CONSTANT_PROTO_H_

extensions/protobuf/internal/ast.cc common/ast/expr_proto.ccextensions/protobuf/internal/ast.cc renamed to common/ast/expr_proto.cc

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#include "extensions/protobuf/internal/ast.h"
+#include "common/ast/expr_proto.h"
 
 #include <algorithm>
 #include <cstddef>
@@ -28,12 +28,12 @@
 #include "absl/status/status.h"
 #include "absl/strings/str_cat.h"
 #include "absl/types/variant.h"
-#include "common/ast.h"
+#include "common/ast/constant_proto.h"
 #include "common/constant.h"
-#include "extensions/protobuf/internal/constant.h"
+#include "common/expr.h"
 #include "internal/status_macros.h"
 
-namespace cel::extensions::protobuf_internal {
+namespace cel::ast_internal {
 
 namespace {
 
@@ -511,4 +511,4 @@ absl::Status ExprFromProto(const cel::expr::Expr& proto, Expr& expr) {
   return state.ExprFromProto(proto, expr);
 }
 
-}  // namespace cel::extensions::protobuf_internal
+}  // namespace cel::ast_internal

extensions/protobuf/internal/ast.h common/ast/expr_proto.hextensions/protobuf/internal/ast.h renamed to common/ast/expr_proto.h

@@ -12,21 +12,21 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#ifndef THIRD_PARTY_CEL_CPP_EXTENSIONS_PROTOBUF_INTERNAL_AST_H_
-#define THIRD_PARTY_CEL_CPP_EXTENSIONS_PROTOBUF_INTERNAL_AST_H_
+#ifndef THIRD_PARTY_CEL_CPP_COMMON_AST_EXPR_PROTO_H_
+#define THIRD_PARTY_CEL_CPP_COMMON_AST_EXPR_PROTO_H_
 
 #include "cel/expr/syntax.pb.h"
 #include "absl/base/nullability.h"
 #include "absl/status/status.h"
 #include "common/expr.h"
 
-namespace cel::extensions::protobuf_internal {
+namespace cel::ast_internal {
 
 absl::Status ExprToProto(const Expr& expr,
                          absl::Nonnull<cel::expr::Expr*> proto);
 
 absl::Status ExprFromProto(const cel::expr::Expr& proto, Expr& expr);
 
-}  // namespace cel::extensions::protobuf_internal
+}  // namespace cel::ast_internal
 
-#endif  // THIRD_PARTY_CEL_CPP_EXTENSIONS_PROTOBUF_INTERNAL_AST_H_
+#endif  // THIRD_PARTY_CEL_CPP_COMMON_AST_EXPR_PROTO_H_

extensions/protobuf/internal/ast_test.cc common/ast/expr_proto_test.ccextensions/protobuf/internal/ast_test.cc renamed to common/ast/expr_proto_test.cc

@@ -12,18 +12,19 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#include "extensions/protobuf/internal/ast.h"
+#include "common/ast/expr_proto.h"
 
 #include <string>
 
 #include "cel/expr/syntax.pb.h"
 #include "absl/status/status.h"
-#include "common/ast.h"
+#include "absl/status/status_matchers.h"
+#include "common/expr.h"
 #include "internal/proto_matchers.h"
 #include "internal/testing.h"
 #include "google/protobuf/text_format.h"
 
-namespace cel::extensions::protobuf_internal {
+namespace cel::ast_internal {
 namespace {
 
 using ::absl_testing::IsOk;
@@ -299,4 +300,4 @@ TEST(ExprFromProto, MapEntryInStruct) {
 }
 
 }  // namespace
-}  // namespace cel::extensions::protobuf_internal
+}  // namespace cel::ast_internal

common/ast_rewrite_test.cc

@@ -19,8 +19,11 @@
 #include <vector>
 
 #include "cel/expr/syntax.pb.h"
+#include "absl/status/status_matchers.h"
 #include "base/ast_internal/ast_impl.h"
+#include "base/ast_internal/expr.h"
 #include "common/ast.h"
+#include "common/ast/expr_proto.h"
 #include "common/ast_visitor.h"
 #include "common/expr.h"
 #include "extensions/protobuf/ast_converters.h"
@@ -32,9 +35,10 @@ namespace cel {
 
 namespace {
 
+using ::absl_testing::IsOk;
 using ::cel::ast_internal::AstImpl;
+using ::cel::ast_internal::ExprFromProto;
 using ::cel::extensions::CreateAstFromParsedExpr;
-using ::cel::extensions::internal::ConvertProtoExprToNative;
 using ::testing::_;
 using ::testing::ElementsAre;
 using ::testing::InSequence;
@@ -543,8 +547,11 @@ TEST(AstRewrite, SelectRewriteExample) {
         ident_expr { name: "com.google.Identifier" }
       )pb",
       &expected_expr);
-  EXPECT_EQ(ast_impl.root_expr(),
-            ConvertProtoExprToNative(expected_expr).value());
+
+  cel::Expr expected_native;
+  ASSERT_THAT(ExprFromProto(expected_expr, expected_native), IsOk());
+
+  EXPECT_EQ(ast_impl.root_expr(), expected_native);
 }
 
 // Rewrites x -> y -> z to demonstrate traversal when a node is rewritten on
@@ -595,8 +602,10 @@ TEST(AstRewrite, PreAndPostVisitExpample) {
         ident_expr { name: "z" }
       )pb",
       &expected_expr);
-  EXPECT_EQ(ast_impl.root_expr(),
-            ConvertProtoExprToNative(expected_expr).value());
+  cel::Expr expected_native;
+  ASSERT_THAT(ExprFromProto(expected_expr, expected_native), IsOk());
+
+  EXPECT_EQ(ast_impl.root_expr(), expected_native);
   EXPECT_THAT(visitor.visited_idents(), ElementsAre("y"));
 }
 

eval/compiler/BUILD

@@ -434,16 +434,19 @@ cc_test(
         "//base:builtins",
         "//base/ast_internal:ast_impl",
         "//base/ast_internal:expr",
+        "//common/ast:expr_proto",
         "//eval/public:builtin_func_registrar",
         "//eval/public:cel_function",
         "//eval/public:cel_function_registry",
         "//extensions/protobuf:ast_converters",
         "//internal:casts",
+        "//internal:proto_matchers",
         "//internal:testing",
         "//runtime:runtime_issue",
         "//runtime:type_registry",
         "//runtime/internal:issue_collector",
         "@com_google_absl//absl/container:flat_hash_map",
+        "@com_google_absl//absl/log:absl_check",
         "@com_google_absl//absl/memory",
         "@com_google_absl//absl/status",
         "@com_google_absl//absl/strings",