ci: add libcpp hardening flags to macOS fuzz job #33462

1. 
   fanquake commented at 2:38 pm on September 23, 2025: member

   Follows up to #33425 (comment).
2. ci: add libcpp hardening flags to macOS fuzz job

   Follows up to
   https://github.com/bitcoin/bitcoin/pull/33425#issuecomment-3323149107.

   c5d8702c3f
3. DrahtBot added the label Tests on Sep 23, 2025
4. 
   DrahtBot commented at 2:38 pm on September 23, 2025: contributor

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/33462.

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5. 
   fanquake commented at 3:11 pm on September 23, 2025: member

   Ah, this probably isn’t doing anything, because we are using the oldest supported Apple Clang here. Will push something else.
6. WIP: use macOS 15 in CI f76eb16cf6
7. fanquake force-pushed on Sep 23, 2025
8. in .github/workflows/ci.yml:149 in f76eb16cf6

   145@@ -146,7 +146,7 @@ jobs:
   146           # doc/release-notes-empty-template.md and providing at least the
   147           # minimum clang version denoted in doc/dependencies.md.
   148           # See: https://developer.apple.com/documentation/xcode-release-notes/xcode-15-release-notes
   149-          sudo xcode-select --switch /Applications/Xcode_15.0.app
   150+          #sudo xcode-select --switch /Applications/Xcode_15.0.app
   

   ---

   ---

   

   maflcko commented at 3:39 pm on September 23, 2025:

   hardening was added in xcode 16: https://developer.apple.com/documentation/xcode-release-notes/xcode-16-release-notes#C++-Standard-Library

    0diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
    1index 52d21ef3ab..a0902e2700 100644
    2--- a/.github/workflows/ci.yml
    3+++ b/.github/workflows/ci.yml
    4@@ -145,8 +145,8 @@ jobs:
    5           # Use the earliest Xcode supported by the version of macOS denoted in
    6           # doc/release-notes-empty-template.md and providing at least the
    7           # minimum clang version denoted in doc/dependencies.md.
    8-          # See: https://developer.apple.com/documentation/xcode-release-notes/xcode-15-release-notes
    9-          sudo xcode-select --switch /Applications/Xcode_15.0.app
   10+          # See: https://developer.apple.com/documentation/xcode-release-notes/xcode-16-release-notes
   11+          sudo xcode-select --switch /Applications/Xcode_16.0.app
   12           clang --version
   13 
   14       - name: Install Homebrew packages
   15diff --git a/doc/release-notes-empty-template.md b/doc/release-notes-empty-template.md
   16index 0e8dc7704e..7f419cbf42 100644
   17--- a/doc/release-notes-empty-template.md
   18+++ b/doc/release-notes-empty-template.md
   19@@ -36,7 +36,7 @@ Compatibility
   20 ==============
   21 
   22 Bitcoin Core is supported and tested on operating systems using the
   23-Linux Kernel 3.17+, macOS 13+, and Windows 10+. Bitcoin
   24+Linux Kernel 3.17+, macOS 14+, and Windows 10+. Bitcoin
   25 Core should also work on most other Unix-like systems but is not as
   26 frequently tested on them. It is not recommended to use Bitcoin Core on
   27 unsupported systems.
   

   and macos 13 is unsupported: https://en.wikipedia.org/wiki/MacOS_Ventura

9. 
   fanquake commented at 6:03 pm on September 23, 2025: member

   Looks like this does pass with the correct Clang (https://github.com/bitcoin/bitcoin/actions/runs/17950891735/job/51049620756#step:3:16):

   0 Apple clang version 17.0.0 (clang-1700.0.13.5)
   1Target: arm64-apple-darwin24.6.0
   2Thread model: posix
   3InstalledDir: /Applications/Xcode_16.4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
   

   with some slowdown. i.e on master:

   0tx_pool_standard: succeeded against 919 files in 22s.
   1utxo_total_supply: succeeded against 831 files in 98s.
   

   in this PR:

   0tx_pool_standard: succeeded against 919 files in 152s.
   1 utxo_total_supply: succeeded against 831 files in 126s.
   

10. 
    maflcko commented at 5:41 pm on September 25, 2025: member

    Concept ACK. The qa-assets repo has a libc++ debug run, so this isn’t required, but it seems fast enough to not hurt.

    Would be nice to push my suggested diff, so that the xcode is hardcoded again.

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