windows: replace deprecated codecvt with fs::u8path #35704

pull kevkevinpal wants to merge 1 commits into bitcoin:master from kevkevinpal:remove-deprecated-codecvt changing 4 files +22 −27

kevkevinpal commented at 9:19 PM on July 12, 2026: contributor

Summary

Remove std::wstring_convert/codecvt (deprecated in C++17, removed in C++26) in favor of fs::u8path().wstring() for UTF-8 to wide conversions.

This should be fine to remove since Bitcoin Core is now on C++20
DrahtBot commented at 9:20 PM on July 12, 2026: contributor


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Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35704.



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Concept ACK hebasto

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Conflicts

Reviewers, this pull request conflicts with the following ones:
- #34995 (iwyu: Fix warnings in src/common and treat them as errors 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.
fanquake commented at 7:54 AM on July 13, 2026: member

cc @hebasto

Type	Reviewers
Concept ACK	hebasto

in src/util/exec.cpp:31 in d8e64c1e85

  26 | @@ -29,16 +27,16 @@ int ExecVp(const char* file, char* const argv[])
  27 |      return execvp(file, argv);
  28 |  #else
  29 |      std::vector<std::wstring> escaped_args;
  30 | -    std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> converter;
  31 |      for (char* const* arg_ptr{argv}; *arg_ptr; ++arg_ptr) {
  32 | -        subprocess::util::quote_argument(converter.from_bytes(*arg_ptr), escaped_args.emplace_back(), false);
  33 | +        subprocess::util::quote_argument(fs::u8path(*arg_ptr).wstring(), escaped_args.emplace_back(), false);

maflcko commented at 8:19 AM on July 13, 2026:

nit: Could use named args here for the bool literal while touching?

kevkevinpal commented at 3:16 PM on July 16, 2026:

Yup, makes sense, and thank you for the review! Updated in abb2983

hebasto commented at 8:26 AM on July 13, 2026: member

Concept ACK.
in src/common/system.cpp:56 in d8e64c1e85
```
  52 | @@ -53,7 +53,7 @@ void runCommand(const std::string& strCommand)
  53 |  #ifndef WIN32
  54 |      int nErr = ::system(strCommand.c_str());
  55 |  #else
  56 | -    int nErr = ::_wsystem(std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>,wchar_t>().from_bytes(strCommand).c_str());
  57 | +    int nErr = ::_wsystem(fs::u8path(strCommand).wstring().c_str());
```
hebasto commented at 3:03 PM on July 14, 2026:

This code was originally added to make runCommand handle UTF-8 command strings. Since #32380, the active code page is guaranteed to be UTF-8, so the narrow ::system() accepts UTF-8 directly and the wide conversion is no longer needed. Therefore, the correct solution here is to revert 23db9546c16c2be264cfc4f695f5738a2f5beeeb

kevkevinpal commented at 3:15 PM on July 16, 2026:

Thank you for the review. This should now be reverted in abb2983
hebasto commented at 3:40 PM on July 14, 2026: member

cc @ryanofsky

windows: replace deprecated codecvt with fs::u8path

Remove std::wstring_convert/codecvt (deprecated in C++17, removed in
C++26) in favor of fs::u8path().wstring() for UTF-8 to wide conversions.

abb29836f5

in src/util/exec.cpp:39 in d8e64c1e85

  37 |      new_argv.reserve(escaped_args.size() + 1);
  38 |      for (const auto& s : escaped_args) new_argv.push_back(s.c_str());
  39 |      new_argv.push_back(nullptr);
  40 | -    return _wexecvp(converter.from_bytes(file).c_str(), new_argv.data());
  41 | +    const std::wstring wfile{fs::u8path(file).wstring()};
  42 | +    return _wexecvp(wfile.c_str(), new_argv.data());

hebasto commented at 4:03 PM on July 14, 2026:

Given #32380, could we use a narrow execvp() here? Perhaps this will require templatizing subprocess::util::quote_argument.

kevkevinpal commented at 3:15 PM on July 16, 2026:

Thank you for the review, this should now be resolved in abb2983

kevkevinpal force-pushed on Jul 16, 2026

Contributors

windows: replace deprecated codecvt with fs::u8path #35704

Summary

Code Coverage & Benchmarks

Reviews

Conflicts