Contradiction between C++ styleguide and cpplint regarding transitive includes

[Geoffrey Viola]

This issue comes from cpplint#218

The Google C++ Style Guide states that

Do not rely on transitive inclusions. This allows people to remove no-longer-needed #include statements from their headers without breaking clients. This also applies to related headers - foo.cc should include bar.h if it uses a symbol from it even if foo.h includes bar.h.

The second part about including the direct dependencies in the source file regardless of the corresponding header, contradicts with cpplint. When cpplint is run on a source file, it counts the includes in its corresponding header file as included.

The policy is that if you #include something in foo.h you don't need to
include it again in foo.cc. Here, we will look at possible includes.

Which rule should be followed?

[Titus Winters]

It's easier for IDEs and other tools to follow the simpler rule in the style guide ("is this symbol provided by a file #included directly in this file?"), so we'd prefer the written rule not the legacy behavior in cpplint.

…

On Sun, Jan 29, 2023 at 11:42 AM Geoffrey Viola ***@***.***> wrote: This issue comes from cpplint#218 <cpplint#218> The Google C++ Style Guide <https://google.github.io/styleguide/cppguide.html#Include_What_You_Use> states that Do not rely on transitive inclusions. This allows people to remove no-longer-needed #include statements from their headers without breaking clients. This also applies to related headers - foo.cc should include bar.h if it uses a symbol from it even if foo.h includes bar.h. The second part about including the direct dependencies in the source file regardless of the corresponding header, contradicts with cpplint. When cpplint <https://github.com/cpplint/cpplint/blob/fa12a0bbdafa15291276ddd2a2dcd2ac7a2ce4cb/cpplint.py#L6127-L6128> is run on a source file, it counts the includes in its corresponding header file as included. The policy is that if you #include something in foo.h you don't need to include it again in foo.cc. Here, we will look at possible includes. Which rule should be followed? — Reply to this email directly, view it on GitHub <#757>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AC7CRX6C42IQPX2WOPDCO53WU2MYVANCNFSM6AAAAAAUKKXV4Q> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

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