refactor: Enable clang-tidy rule to reject anon namespace in header #35895

1. 
   maflcko commented at 9:24 AM on August 5, 2026: member

   This avoids issues like #35737 from passing CI in the first place.

   Also, the rule can help to avoid ODR issues, according to https://clang.llvm.org/extra/clang-tidy/checks/fuchsia/header-anon-namespaces.html

   This follows https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#sf21-dont-use-an-unnamed-anonymous-namespace-in-a-header

2. refactor: Use C++20 std::identity over IntIdentity fafe5042bd
3. refactor: Enable clang-tidy rule to reject anon namespace in header

   The rule is named misc-anonymous-namespace-in-header in clang-tidy-22,
   but use fuchsia-header-anon-namespaces for compat with clang-tidy-21.

   fa5ca877b6
4. DrahtBot renamed this:
   refactor: Enable clang-tidy rule to reject anon namespace in header
   refactor: Enable clang-tidy rule to reject anon namespace in header
   on Aug 5, 2026
5. DrahtBot added the label Refactoring on Aug 5, 2026
6. 
   DrahtBot commented at 9:24 AM on August 5, 2026: contributor

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   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35895.

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7. refactor: Enable misc-definitions-in-headers fa93132d6d
8. hebasto approved
9. 
   hebasto commented at 9:57 AM on August 5, 2026: member

   ACK fa5ca877b60339c858b5045f855ae0256e63b69d.

10. 
    maflcko commented at 10:11 AM on August 5, 2026: member

    Hmm, https://clang.llvm.org/extra/clang-tidy/checks/misc/definitions-in-headers.html has some similar ODR checks, and it is passing, so might as well enable it in a separate commit here.

    <strike>Also, https://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines/interfaces-global-init.html, which should be the last check we care about to enable for globals.</strike>

11. DrahtBot added the label CI failed on Aug 5, 2026
12. maflcko force-pushed on Aug 5, 2026
13. maflcko removed the label CI failed on Aug 5, 2026
14. DrahtBot added the label CI failed on Aug 5, 2026
15. 
    DrahtBot commented at 10:37 AM on August 5, 2026: contributor

    <!--85328a0da195eb286784d51f73fa0af9-->

    🚧 At least one of the CI tasks failed. _{Task tidy: https://github.com/bitcoin/bitcoin/actions/runs/30996402317/job/92274495762} _{LLM reason (✨ experimental): Clang-tidy failed due to cppcoreguidelines-interfaces-global-init errors (warnings-as-errors) from CAPNP-generated *.capnp.c++ files initializing non-local globals using uninitialized variables.}

    <details><summary>Hints</summary>

    Try to run the tests locally, according to the documentation. However, a CI failure may still happen due to a number of reasons, for example:

    • Possibly due to a silent merge conflict (the changes in this pull request being incompatible with the current code in the target branch). If so, make sure to rebase on the latest commit of the target branch.

    • A sanitizer issue, which can only be found by compiling with the sanitizer and running the affected test.

    • An intermittent issue.

    Leave a comment here, if you need help tracking down a confusing failure.

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16. DrahtBot removed the label CI failed on Aug 5, 2026
17. in src/.clang-tidy:11 in fa93132d6d

       7 | @@ -8,8 +8,10 @@ bugprone-use-after-move,
       8 |  bugprone-lambda-function-name,
       9 |  bugprone-unhandled-self-assignment,
      10 |  bugprone-unused-return-value,
      11 | -misc-unused-using-decls,
      12 | +fuchsia-header-anon-namespaces,
    

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    ---

    

    sedited commented at 12:06 PM on August 5, 2026:

    Why is this using an alias: https://clang.llvm.org/extra/clang-tidy/checks/fuchsia/header-anon-namespaces.html ?

    ---

    

    maflcko commented at 12:44 PM on August 5, 2026:

    It is in the commit message, but no strong opinion. Happy to push whatever name the reviewers want.

18. sedited approved
19. 
    sedited commented at 12:49 PM on August 5, 2026: contributor

    ACK fa93132d6da508597205513725ba4663d3a24954

20. DrahtBot requested review from hebasto on Aug 5, 2026
21. fanquake merged this on Aug 5, 2026
22. fanquake closed this on Aug 5, 2026

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23. maflcko deleted the branch on Aug 5, 2026

Contributors

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Review Requested
hebasto