depends: patch Qt rounding bugs #32081

1. 
   fanquake commented at 8:14 am on March 17, 2025: member

   When compiled under -O0, this code was causing runtime failures in the 32-bit Clang gui wallet tests. Work around that by importing a commit from upstream: https://github.com/qt/qtbase/commit/8c8b9a4173f4add522ec13de85107deba7c82da0.

   Can be recreated with:

   0make -C depends/ DEBUG=1 CFLAGS="-O0" CXXFLAGS="-O0" HOST=i686-pc-linux-gnu
   1cmake -B build --toolchain /root/ci_scratch/depends/i686-pc-linux-gnu/toolchain.cmake -DCMAKE_BUILD_TYPE=Debug -DCMAKE_C_COMPILER='clang;-m32' -DCMAKE_CXX_COMPILER='clang++;-m32'
   2cmake --build build
   3ctest --test-dir build
   

   Test failure output: https://gist.github.com/fanquake/16535691162170dc313b8f9f80988fa9.

   Split from #29796.

2. 
   DrahtBot commented at 8:14 am on March 17, 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/32081.

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   Type	Reviewers
   ACK	ryanofsky

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   Conflicts

   Reviewers, this pull request conflicts with the following ones:

   • #30997 (build: Switch to Qt 6 by hebasto)

   If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

3. DrahtBot added the label Build system on Mar 17, 2025
4. depends: patch qt rounding bugs

   When compiled under -O0, this code was causing runtime failures in the
   32-bit Clang gui wallet tests. Work around that by importing a commit from upstream:
   https://github.com/qt/qtbase/commit/8c8b9a4173f4add522ec13de85107deba7c82da0.

   9ca76aa421
5. fanquake force-pushed on Mar 20, 2025
6. DrahtBot added the label CI failed on Mar 20, 2025
7. DrahtBot removed the label CI failed on Mar 20, 2025
8. ryanofsky approved
9. 
   ryanofsky commented at 6:35 pm on March 27, 2025: contributor

   Code review ACK 9ca76aa4210d15060fe35eb95da0862af57a8cc9

   Reviewed by comparing https://github.com/qt/qtbase/commit/8c8b9a4173f4add522ec13de85107deba7c82da0.patch and https://github.com/fanquake/bitcoin/raw/refs/heads/fix_qt_32_O0/depends/patches/qt/normalize_round.patch and confirming they are effectively the same patch.

10. 
    maflcko commented at 9:16 pm on March 27, 2025: member

    I guess this won’t be needed after #30997 (assuming that it makes it in for the next release)

Contributors
fanquake DrahtBot ryanofsky maflcko

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