Create independent build target for string.format()

`string.format()` pulls in extra dependencies like ICU4C for locale support. Not all users need formatting. If everything is bundled in the strings extensions, all users need to pay for the extra dependency. By putting it in its own build target, users can opt in.

PiperOrigin-RevId: 719338589

Author: CEL Dev Team

extensions/BUILD

@@ -439,22 +439,15 @@ cc_test(
 
 cc_library(
     name = "strings",
-    srcs = [
-        "formatting.cc",
-        "strings.cc",
-    ],
-    hdrs = [
-        "formatting.h",
-        "strings.h",
-    ],
+    srcs = ["strings.cc"],
+    hdrs = ["strings.h"],
     deps = [
         "//checker:type_checker_builder",
         "//checker/internal:builtins_arena",
         "//common:casting",
         "//common:decl",
         "//common:type",
         "//common:value",
-        "//common:value_kind",
         "//eval/public:cel_function_registry",
         "//eval/public:cel_options",
         "//internal:status_macros",
@@ -463,19 +456,12 @@ cc_library(
         "//runtime:function_registry",
         "//runtime:runtime_options",
         "//runtime/internal:errors",
-        "@com_google_absl//absl/base:core_headers",
         "@com_google_absl//absl/base:no_destructor",
-        "@com_google_absl//absl/container:btree",
-        "@com_google_absl//absl/memory",
-        "@com_google_absl//absl/numeric:bits",
         "@com_google_absl//absl/status",
         "@com_google_absl//absl/status:statusor",
         "@com_google_absl//absl/strings",
         "@com_google_absl//absl/strings:cord",
-        "@com_google_absl//absl/strings:str_format",
         "@com_google_absl//absl/strings:string_view",
-        "@com_google_absl//absl/time",
-        "@icu4c",
     ],
 )
 
@@ -593,11 +579,36 @@ cc_test(
     ],
 )
 
+cc_library(
+    name = "formatting",
+    srcs = ["formatting.cc"],
+    hdrs = ["formatting.h"],
+    deps = [
+        "//common:value",
+        "//common:value_kind",
+        "//internal:status_macros",
+        "//runtime:function_adapter",
+        "//runtime:function_registry",
+        "//runtime:runtime_options",
+        "@com_google_absl//absl/base:core_headers",
+        "@com_google_absl//absl/container:btree",
+        "@com_google_absl//absl/memory",
+        "@com_google_absl//absl/numeric:bits",
+        "@com_google_absl//absl/status",
+        "@com_google_absl//absl/status:statusor",
+        "@com_google_absl//absl/strings",
+        "@com_google_absl//absl/strings:str_format",
+        "@com_google_absl//absl/strings:string_view",
+        "@com_google_absl//absl/time",
+        "@icu4c",
+    ],
+)
+
 cc_test(
     name = "formatting_test",
     srcs = ["formatting_test.cc"],
     deps = [
-        ":strings",
+        ":formatting",
         "//common:allocator",
         "//common:value",
         "//extensions/protobuf:runtime_adapter",

extensions/formatting.cc

@@ -582,8 +582,6 @@ absl::StatusOr<Value> Format(ValueManager& value_manager,
 
 }  // namespace
 
-namespace strings_internal {
-
 absl::Status RegisterStringFormattingFunctions(FunctionRegistry& registry,
                                                const RuntimeOptions& options) {
   auto locale = icu::Locale::createCanonical(options.locale.c_str());
@@ -603,5 +601,4 @@ absl::Status RegisterStringFormattingFunctions(FunctionRegistry& registry,
   return absl::OkStatus();
 }
 
-}  // namespace strings_internal
 }  // namespace cel::extensions

extensions/formatting.h

@@ -19,12 +19,12 @@
 #include "runtime/function_registry.h"
 #include "runtime/runtime_options.h"
 
-namespace cel::extensions::strings_internal {
+namespace cel::extensions {
 
 // Register extension functions for string formatting.
 absl::Status RegisterStringFormattingFunctions(FunctionRegistry& registry,
                                                const RuntimeOptions& options);
 
-}  // namespace cel::extensions::strings_internal
+}  // namespace cel::extensions
 
 #endif  // THIRD_PARTY_CEL_CPP_EXTENSIONS_FORMATTING_H_

extensions/formatting_test.cc

@@ -89,8 +89,7 @@ TEST_P(StringFormatTest, TestStringFormatting) {
                        CreateStandardRuntimeBuilder(
                            internal::GetTestingDescriptorPool(), options));
   auto registration_status =
-      strings_internal::RegisterStringFormattingFunctions(
-          builder.function_registry(), options);
+      RegisterStringFormattingFunctions(builder.function_registry(), options);
   if (test_case.error.has_value() && !registration_status.ok()) {
     EXPECT_THAT(registration_status.message(), HasSubstr(*test_case.error));
     return;

extensions/strings.cc

@@ -36,7 +36,6 @@
 #include "common/value_manager.h"
 #include "eval/public/cel_function_registry.h"
 #include "eval/public/cel_options.h"
-#include "extensions/formatting.h"
 #include "internal/status_macros.h"
 #include "internal/utf8.h"
 #include "runtime/function_adapter.h"
@@ -432,8 +431,6 @@ absl::Status RegisterStringsFunctions(FunctionRegistry& registry,
           int64_t>::CreateDescriptor("replace", /*receiver_style=*/true),
       VariadicFunctionAdapter<absl::StatusOr<Value>, StringValue, StringValue,
                               StringValue, int64_t>::WrapFunction(Replace2)));
-  CEL_RETURN_IF_ERROR(
-      strings_internal::RegisterStringFormattingFunctions(registry, options));
   return absl::OkStatus();
 }
 

extensions/strings_test.cc

@@ -228,29 +228,6 @@ TEST(Strings, UpperAscii) {
   EXPECT_TRUE(result.GetBool().NativeValue());
 }
 
-TEST(Strings, Format) {
-  google::protobuf::Arena arena;
-  const auto options = RuntimeOptions{};
-  ASSERT_OK_AND_ASSIGN(auto builder,
-                       CreateStandardRuntimeBuilder(
-                           internal::GetTestingDescriptorPool(), options));
-  EXPECT_THAT(RegisterStringsFunctions(builder.function_registry(), options),
-              IsOk());
-
-  ASSERT_OK_AND_ASSIGN(auto runtime, std::move(builder).Build());
-
-  ASSERT_OK_AND_ASSIGN(ParsedExpr expr, Parse("'abc %d'.format([2]) == 'abc 2'",
-                                              "<input>", ParserOptions{}));
-
-  ASSERT_OK_AND_ASSIGN(std::unique_ptr<Program> program,
-                       ProtobufRuntimeAdapter::CreateProgram(*runtime, expr));
-
-  Activation activation;
-  ASSERT_OK_AND_ASSIGN(Value result, program->Evaluate(&arena, activation));
-  ASSERT_TRUE(result.Is<BoolValue>());
-  EXPECT_TRUE(result.GetBool().NativeValue());
-}
-
 TEST(StringsCheckerLibrary, SmokeTest) {
   google::protobuf::Arena arena;
   ASSERT_OK_AND_ASSIGN(