[PATCH] D142123: [clang-tidy] Add check to suggest use of #pragma once

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added a comment.

In D142123#4066564 <https://reviews.llvm.org/D142123#4066564>, @KyleFromKitware wrote:

> In terms of a "generic check", there is already the `HeaderGuardCheck`, but that has to be extended to be specific to the project's naming convention. And I don't think there can be a generic check that converts `#pragma once` to a header guard - when it adds the header guard, what does it name it? It has to know the project's naming convention.

It doesn't have to -- for example, we can name the guard based on the path to the header. e.g., `foo/include/bar/baz.h` could use `FOO_INCLUDE_BAR_BAZ_H` as the header guard.

> If we want a check that replaces `#pragma once` with a header guard, our best bet would be modifying `HeaderGuardCheck` to do this, since it already does most of the needed work. However, such functionality is orthogonal to my proposal here.

It's orthogonal except for the design concerns. Basically, I don't think we should have one check for "go to header guards" and another check for "go to pragma once" -- IMO we should have one check to do either approach. @njames93 is correct that a common use case for clang-tidy is "enable all checks" so having two checks that do opposite things gets awkward in practice.


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https://reviews.llvm.org/D142123