Use std::optional/string_view

[cyyever]

Summary

This PR changes callers to use std::optional/string_view.

Test plan

Check whether the system can build.

[pytorch-bot]

🔗 Helpful Links

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[cyyever]

@pytorchbot label "release notes: none"

[rascani]

Thanks for making this change!

Does this remove all uses of torch::executor::optional and executorch::runtime::etensor::optional? If so, then it would probably be good to remove those type aliases to ensure new usages don't get re-introduced.

There are a few clang-format errors coming from lintrunner that need to be cleaned up.

[cyyever]

@rascani I added more cleanup and fixed the linters.

[rascani]

I'm sorry @cyyever, I gave you bad advice. We won't be able to remove the type aliases or header files as they are part of the public API and are subject to the API Life Cycle and Deprecation Policy. We'll need to mark them as deprecated first, and cannot remove them for 2 minor releases.

Here's an example of how the optional aliases would look:

#include <optional>
#include <executorch/runtime/platform/compiler.h>

namespace executorch::runtime::etensor {
template <typename T>
using optional ET_DEPRECATED = std::optional<T>;
using nullopt_t ET_DEPRECATED = std::nullopt_t;
ET_DEPRECATED inline constexpr std::nullopt_t nullopt{std::nullopt};
}  // namespace executorch::runtime::etensor

namespace torch::executor {  // legacy spelling
template <typename T>
using optional ET_DEPRECATED = std::optional<T>;
using nullopt_t ET_DEPRECATED = std::nullopt_t;
ET_DEPRECATED inline constexpr std::nullopt_t nullopt{std::nullopt};
}  // namespace torch::executor

I'll put up a separate PR for adding message support to ET_DEPRECATED, so ideally we could do:

template <typename T>
using optional ET_DEPRECATED("use std::optional; removal in 1.6") = std::optional<T>;

[nil-is-all]

I'm sorry @cyyever, I gave you bad advice. We won't be able to remove the type aliases or header files as they are part of the public API and are subject to the API Life Cycle and Deprecation Policy. We'll need to mark them as deprecated first, and cannot remove them for 2 minor releases.

Here's an example of how the optional aliases would look:

#include <optional>
#include <executorch/runtime/platform/compiler.h>

namespace executorch::runtime::etensor {
template <typename T>
using optional ET_DEPRECATED = std::optional<T>;
using nullopt_t ET_DEPRECATED = std::nullopt_t;
ET_DEPRECATED inline constexpr std::nullopt_t nullopt{std::nullopt};
}  // namespace executorch::runtime::etensor

namespace torch::executor {  // legacy spelling
template <typename T>
using optional ET_DEPRECATED = std::optional<T>;
using nullopt_t ET_DEPRECATED = std::nullopt_t;
ET_DEPRECATED inline constexpr std::nullopt_t nullopt{std::nullopt};
}  // namespace torch::executor

I'll put up a separate PR for adding message support to ET_DEPRECATED, so ideally we could do:

template <typename T>
using optional ET_DEPRECATED("use std::optional; removal in 1.6") = std::optional<T>;

Hi @rascani, in that case do we close this PR for now?

[rascani]

I'm sorry @cyyever, I gave you bad advice. We won't be able to remove the type aliases or header files as they are part of the public API and are subject to the API Life Cycle and Deprecation Policy. We'll need to mark them as deprecated first, and cannot remove them for 2 minor releases.
Here's an example of how the optional aliases would look:

#include <optional>
#include <executorch/runtime/platform/compiler.h>

namespace executorch::runtime::etensor {
template <typename T>
using optional ET_DEPRECATED = std::optional<T>;
using nullopt_t ET_DEPRECATED = std::nullopt_t;
ET_DEPRECATED inline constexpr std::nullopt_t nullopt{std::nullopt};
}  // namespace executorch::runtime::etensor

namespace torch::executor {  // legacy spelling
template <typename T>
using optional ET_DEPRECATED = std::optional<T>;
using nullopt_t ET_DEPRECATED = std::nullopt_t;
ET_DEPRECATED inline constexpr std::nullopt_t nullopt{std::nullopt};
}  // namespace torch::executor

I'll put up a separate PR for adding message support to ET_DEPRECATED, so ideally we could do:

template <typename T>
using optional ET_DEPRECATED("use std::optional; removal in 1.6") = std::optional<T>;

Hi @rascani, in that case do we close this PR for now?

No, not unless any other maintainer objects to deprecating the optional/string_view aliases.

When we add the ET_DEPRECATED macro, we'll start getting compiler warnings on all uses in the executorch codebase. The bulk of this PR is the migration of those uses to the std:: equivalents.

We just need to revert the header file removals and add the ET_DEPRECATED macros.

[cyyever]

@rascani @nil-is-all Restored them and added ET_DEPRECATED

[rascani]

@cyyever - Can you revert the last commit 901df7a? It looks like that clang-format run disagreed with the clang-format that is run by lintrunner (could be different versions or config).