New conformance fixes

Removes the string format library in favor of cel-cpp's standard implementation. This causes some tests to be fixed, but it also causes some new failures due to non-standard string formatting behavior in protovalidate. This will be fixed on the next protovalidate release, so we should probably release that and then update this PR with it before merging.

Author: jchadwick-buf

buf/validate/conformance/expected_failures.yaml

@@ -109,6 +109,7 @@ cc_library(
         "@com_github_bufbuild_protovalidate//proto/protovalidate/buf/validate:validate_proto_cc",
         "@com_google_cel_cpp//eval/public:activation",
         "@com_google_cel_cpp//eval/public:builtin_func_registrar",
+        "@com_google_cel_cpp//eval/public:string_extension_func_registrar",
         "@com_google_cel_cpp//eval/public:cel_expr_builder_factory",
         "@com_google_cel_cpp//eval/public:cel_expression",
         "@com_google_cel_cpp//eval/public/containers:field_access",
@@ -132,7 +133,6 @@ cc_library(
     srcs = ["extra_func.cc"],
     hdrs = ["extra_func.h"],
     deps = [
-        ":string_format",
         "//buf/validate/internal/lib:ipv4",
         "//buf/validate/internal/lib:ipv6",
         "//buf/validate/internal/lib:uri",
@@ -144,24 +144,6 @@ cc_library(
     ],
 )
 
-cc_library(
-    name = "string_format",
-    srcs = ["string_format.cc"],
-    hdrs = ["string_format.h"],
-    deps = [
-        "@com_google_cel_cpp//eval/public:cel_value",
-    ],
-)
-
-cc_test(
-    name = "string_format_test",
-    srcs = ["string_format_test.cc"],
-    deps = [
-        ":string_format",
-        "@com_google_googletest//:gtest_main",
-    ],
-)
-
 cc_test(
     name = "extra_func_test",
     srcs = ["extra_func_test.cc"],

buf/validate/internal/BUILD.bazel

@@ -22,6 +22,7 @@
 #include "eval/public/containers/field_access.h"
 #include "eval/public/containers/field_backed_list_impl.h"
 #include "eval/public/containers/field_backed_map_impl.h"
+#include "eval/public/string_extension_func_registrar.h"
 #include "eval/public/structs/cel_proto_wrapper.h"
 #include "google/protobuf/dynamic_message.h"
 #include "google/protobuf/util/message_differencer.h"
@@ -105,6 +106,10 @@ NewConstraintBuilder(google::protobuf::Arena* arena) {
   if (!register_status.ok()) {
     return register_status;
   }
+  register_status = cel::runtime::RegisterStringExtensionFunctions(builder->GetRegistry());
+  if (!register_status.ok()) {
+    return register_status;
+  }
   register_status = RegisterExtraFuncs(*builder->GetRegistry(), arena);
   if (!register_status.ok()) {
     return register_status;

buf/validate/internal/constraints.cc

@@ -22,7 +22,6 @@
 #include "buf/validate/internal/lib/ipv4.h"
 #include "buf/validate/internal/lib/ipv6.h"
 #include "buf/validate/internal/lib/uri.h"
-#include "buf/validate/internal/string_format.h"
 #include "eval/public/cel_function_adapter.h"
 #include "eval/public/cel_value.h"
 #include "eval/public/containers/container_backed_map_impl.h"
@@ -230,7 +229,7 @@ bool IsHostAndPort(const std::string_view str, const bool portRequired) {
 
   const auto splitIdx = str.rfind(':');
   if (str.front() == '[') {
-    const auto end = str.find(']');
+    const auto end = str.rfind(']');
     const auto afterEnd = end + 1;
     if (afterEnd == str.size()) { // no port
       const auto host = str.substr(1, end - 1);
@@ -339,19 +338,6 @@ cel::CelValue isUriRef(google::protobuf::Arena* arena, cel::CelValue::StringHold
 
 absl::Status RegisterExtraFuncs(
     google::api::expr::runtime::CelFunctionRegistry& registry, google::protobuf::Arena* regArena) {
-  auto* formatter = google::protobuf::Arena::Create<StringFormat>(regArena);
-  auto status = cel::FunctionAdapter<cel::CelValue, cel::CelValue::StringHolder, cel::CelValue>::
-      CreateAndRegister(
-          "format",
-          true,
-          [formatter](
-              google::protobuf::Arena* arena,
-              cel::CelValue::StringHolder format,
-              cel::CelValue arg) -> cel::CelValue { return formatter->format(arena, format, arg); },
-          &registry);
-  if (!status.ok()) {
-    return status;
-  }
   auto isNanStatus = cel::FunctionAdapter<cel::CelValue, cel::CelValue>::CreateAndRegister(
       "isNan", true, &isNan, &registry);
   if (!isNanStatus.ok()) {

buf/validate/internal/extra_func.cc

@@ -56,4 +56,5 @@ TEST(ExtraFuncTest, TestIpPrefix) {
   // Additional Tests for IsHostAndPort()
   EXPECT_FALSE(buf::validate::internal::IsHostAndPort("example.com:00", false));
   EXPECT_FALSE(buf::validate::internal::IsHostAndPort("example.com:080", false));
+  EXPECT_TRUE(buf::validate::internal::IsHostAndPort("[::0%00]]", false));
 }