Function for conversion of string to bool

PiperOrigin-RevId: 753731195

Author: CEL Dev Team

conformance/BUILD

@@ -224,9 +224,6 @@ _TESTS_TO_SKIP_MODERN = [
     "string_ext/quote",
     "string_ext/value_errors",
     "string_ext/type_errors",
-
-    # TODO(uncreated-issue/77): Add missing conversion function
-    "conversions/bool",
 ]
 
 _TESTS_TO_SKIP_MODERN_DASHBOARD = [
@@ -286,9 +283,6 @@ _TESTS_TO_SKIP_LEGACY = [
     "proto3/set_null/list_value",
     "proto3/set_null/single_struct",
 
-    # TODO(uncreated-issue/77): Add missing conversion function
-    "conversions/bool",
-
     # cel.@block
     "block_ext/basic/optional_list",
     "block_ext/basic/optional_map",

runtime/standard/type_conversion_functions.cc

@@ -44,8 +44,27 @@ using ::cel::internal::MinTimestamp;
 absl::Status RegisterBoolConversionFunctions(FunctionRegistry& registry,
                                              const RuntimeOptions&) {
   // bool -> bool
-  return UnaryFunctionAdapter<bool, bool>::RegisterGlobalOverload(
-      cel::builtin::kBool, [](bool v) { return v; }, registry);
+  absl::Status status =
+      UnaryFunctionAdapter<bool, bool>::RegisterGlobalOverload(
+          cel::builtin::kBool, [](bool v) { return v; }, registry);
+  CEL_RETURN_IF_ERROR(status);
+
+  // string -> bool
+  return UnaryFunctionAdapter<Value, StringValue>::RegisterGlobalOverload(
+      cel::builtin::kBool,
+      [](const StringValue& v) -> Value {
+        if ((v == "true") || (v == "True") || (v == "TRUE") || (v == "t") ||
+            (v == "1")) {
+          return TrueValue();
+        } else if ((v == "false") || (v == "FALSE") || (v == "False") ||
+                   (v == "f") || (v == "0")) {
+          return FalseValue();
+        } else {
+          return ErrorValue(absl::InvalidArgumentError(
+              "Type conversion error from 'string' to 'bool'"));
+        }
+      },
+      registry);
 }
 
 absl::Status RegisterIntConversionFunctions(FunctionRegistry& registry,

runtime/standard/type_conversion_functions_test.cc

@@ -39,9 +39,11 @@ TEST(RegisterTypeConversionFunctions, RegisterBoolConversionFunctions) {
 
   ASSERT_OK(RegisterTypeConversionFunctions(registry, options));
 
-  EXPECT_THAT(registry.FindStaticOverloads(builtin::kBool, false, {Kind::kAny}),
-              UnorderedElementsAre(
-                  MatchesUnaryDescriptor(builtin::kBool, false, Kind::kBool)));
+  EXPECT_THAT(
+      registry.FindStaticOverloads(builtin::kBool, false, {Kind::kAny}),
+      UnorderedElementsAre(
+          MatchesUnaryDescriptor(builtin::kBool, false, Kind::kBool),
+          MatchesUnaryDescriptor(builtin::kBool, false, Kind::kString)));
 }
 
 TEST(RegisterTypeConversionFunctions, RegisterIntConversionFunctions) {