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https://github.com/carbon-language/carbon-lang.git
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Calvin
dcfccd3187
### Context & Motivation The error handling utilities in `//base/error.h` are very useful for writing code with strong safety guarantees. While hardening the `Dump` debug utilities (from review in #4866), I encountered a rough edge with references and pointers. After a [brief Discord discussion in #contributing-help](https://discord.com/channels/655572317891461132/1052653651895779359/1334675462877610038), it was suggested that adding support for references to `ErrorOr` would be a good candidate to move forward. Using a reference type with the `ErrorOr` class (e.g. `ErrorOr<Node&>`) produces two errors: <ol> <li><strong><code>variant can not have a reference type as an alternative</code></strong> <ul><li>From private field: <code>std::variant<Error, T> val_;</code></li></ul> </li> <li><strong><code>'operator->' declared as a pointer to a reference</code></strong> <ul><li>From member function: <code>auto operator->() -> T*</code></li></ul> </li> </ol> ### Changes To support reference types, both errors are resolved: 1. `std::reference_wrapper` is conditionally used for storage when `T` is a reference type 2. type trait aliases like `using ValueT = std::remove_reference_t<T>` are used to produce compatible types for methods like `auto operator->() -> ValueT*`
124 lines
3.1 KiB
C++
124 lines
3.1 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#include "common/error.h"
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#include <gtest/gtest.h>
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#include "common/error_test_helpers.h"
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#include "common/raw_string_ostream.h"
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namespace Carbon {
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namespace {
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using ::Carbon::Testing::IsError;
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using ::Carbon::Testing::IsSuccess;
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using ::testing::Eq;
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TEST(ErrorTest, Error) {
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Error err("test");
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EXPECT_EQ(err.message(), "test");
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}
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TEST(ErrorTest, ErrorEmptyString) {
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ASSERT_DEATH({ Error err(""); }, "CHECK failure at");
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}
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auto IndirectError() -> Error { return Error("test"); }
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TEST(ErrorTest, IndirectError) { EXPECT_EQ(IndirectError().message(), "test"); }
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TEST(ErrorTest, ErrorOr) {
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ErrorOr<int> err(Error("test"));
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EXPECT_THAT(err, IsError("test"));
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}
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TEST(ErrorTest, ErrorOrValue) { EXPECT_TRUE(ErrorOr<int>(0).ok()); }
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auto IndirectErrorOrTest() -> ErrorOr<int> { return Error("test"); }
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TEST(ErrorTest, IndirectErrorOr) { EXPECT_FALSE(IndirectErrorOrTest().ok()); }
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struct Val {
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int val;
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};
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TEST(ErrorTest, ErrorOrArrowOp) {
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ErrorOr<Val> err({1});
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EXPECT_EQ(err->val, 1);
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}
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TEST(ErrorTest, ErrorOrReference) {
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Val val = {1};
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ErrorOr<Val&> maybe_val(val);
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EXPECT_EQ(maybe_val->val, 1);
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}
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auto IndirectErrorOrSuccessTest() -> ErrorOr<Success> { return Success(); }
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TEST(ErrorTest, IndirectErrorOrSuccess) {
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EXPECT_TRUE(IndirectErrorOrSuccessTest().ok());
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}
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TEST(ErrorTest, ReturnIfErrorNoError) {
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auto result = []() -> ErrorOr<Success> {
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CARBON_RETURN_IF_ERROR(ErrorOr<Success>(Success()));
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CARBON_RETURN_IF_ERROR(ErrorOr<Success>(Success()));
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return Success();
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}();
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EXPECT_TRUE(result.ok());
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}
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TEST(ErrorTest, ReturnIfErrorHasError) {
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auto result = []() -> ErrorOr<Success> {
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CARBON_RETURN_IF_ERROR(ErrorOr<Success>(Success()));
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CARBON_RETURN_IF_ERROR(ErrorOr<Success>(Error("error")));
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return Success();
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}();
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EXPECT_THAT(result, IsError("error"));
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}
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TEST(ErrorTest, AssignOrReturnNoError) {
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auto result = []() -> ErrorOr<int> {
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CARBON_ASSIGN_OR_RETURN(int a, ErrorOr<int>(1));
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CARBON_ASSIGN_OR_RETURN(const int b, ErrorOr<int>(2));
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int c = 0;
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CARBON_ASSIGN_OR_RETURN(c, ErrorOr<int>(3));
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return a + b + c;
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}();
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EXPECT_THAT(result, IsSuccess(Eq(6)));
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}
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TEST(ErrorTest, AssignOrReturnHasDirectError) {
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auto result = []() -> ErrorOr<int> {
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CARBON_RETURN_IF_ERROR(ErrorOr<int>(Error("error")));
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return 0;
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}();
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EXPECT_THAT(result, IsError("error"));
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}
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TEST(ErrorTest, AssignOrReturnHasErrorInExpected) {
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auto result = []() -> ErrorOr<int> {
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CARBON_ASSIGN_OR_RETURN(int a, ErrorOr<int>(Error("error")));
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return a;
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}();
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EXPECT_THAT(result, IsError("error"));
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}
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TEST(ErrorTest, ErrorBuilderOperatorImplicitCast) {
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ErrorOr<int> result = ErrorBuilder() << "msg";
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EXPECT_THAT(result, IsError("msg"));
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}
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TEST(ErrorTest, StreamError) {
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Error result = ErrorBuilder("TestFunc") << "msg";
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RawStringOstream result_stream;
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result_stream << result;
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EXPECT_EQ(result_stream.TakeStr(), "TestFunc: msg");
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}
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} // namespace
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} // namespace Carbon
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