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treewide: Remove toView() because it leads to segfaults when compiled with newer nixpkgs

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Firstly, this is now available on darwin where the default in llvm 19.
Secondly, this leads to very weird segfaults when building with newer nixpkgs for some reason.
(It's UB after all).

This appears when building with the following:

mesonComponentOverrides = finalAttrs: prevAttrs: {
mesonBuildType = "debugoptimized";
dontStrip = true;
doCheck = false;
separateDebugInfo = false;
preConfigure = (prevAttrs.preConfigure or "") + ''
  case "$mesonBuildType" in
  release|minsize|debugoptimized) appendToVar mesonFlags "-Db_lto=true"  ;;
  *)                              appendToVar mesonFlags "-Db_lto=false" ;;
  esac
'';
};

And with the following nixpkgs input:

nix build ".#nix-cli" -L --override-input nixpkgs "https://releases.nixos.org/nixos/unstable/nixos-25.11pre870157.7df7ff7d8e00/nixexprs.tar.xz"

Stacktrace:

 #0  0x00000000006afdc0 in ?? ()
 #1  0x00007ffff71cebb6 in _Unwind_ForcedUnwind_Phase2 () from /nix/store/41ym1jm1b7j3rhglk82gwg9jml26z1km-gcc-14.3.0-lib/lib/libgcc_s.so.1
 #2  0x00007ffff71cf5b5 in _Unwind_Resume () from /nix/store/41ym1jm1b7j3rhglk82gwg9jml26z1km-gcc-14.3.0-lib/lib/libgcc_s.so.1
 #3  0x00007ffff7eac7d8 in std::basic_ios<char, std::char_traits<char> >::~basic_ios (this=<optimized out>, this=<optimized out>)
     at /nix/store/82kmz7r96navanrc2fgckh2bamiqrgsw-gcc-14.3.0/include/c++/14.3.0/bits/basic_ios.h:286
 #4  std::__cxx11::basic_ostringstream<char, std::char_traits<char>, std::allocator<char> >::basic_ostringstream (this=<optimized out>, this=<optimized out>)
     at /nix/store/82kmz7r96navanrc2fgckh2bamiqrgsw-gcc-14.3.0/include/c++/14.3.0/sstream:806
 #5  nix::SimpleLogger::logEI (this=<optimized out>, ei=...) at ../logging.cc:121
 #6  0x00007ffff7515794 in nix::Logger::logEI (this=0x675450, lvl=nix::lvlError, ei=...) at /nix/store/bkshji3nnxmrmgwa4n2kaxadajkwvn65-nix-util-2.32.0pre-dev/include/nix/util/logging.hh:144
 #7  nix::handleExceptions (programName=..., fun=...) at ../shared.cc:336
 #8  0x000000000047b76b in main (argc=<optimized out>, argv=<optimized out>) at /nix/store/82kmz7r96navanrc2fgckh2bamiqrgsw-gcc-14.3.0/include/c++/14.3.0/bits/new_allocator.h:88
This commit is contained in:
Sergei Zimmerman 2025-10-05 02:30:21 +03:00
parent 35d7719f46
commit dce1a893d0
No known key found for this signature in database
13 changed files with 16 additions and 38 deletions
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5
src/libutil/include/nix/util/strings.hh
View file

@ -12,11 +12,6 @@
namespace nix {
/*
* workaround for unavailable view() method (C++20) of std::ostringstream under MacOS with clang-16
*/
std::string_view toView(const std::ostringstream & os);
/**
* String tokenizer.
*

2
src/libutil/logging.cc
View file

@ -121,7 +121,7 @@ public:
std::ostringstream oss;
showErrorInfo(oss, ei, loggerSettings.showTrace.get());
log(ei.level, toView(oss));
log(ei.level, oss.view());
}
void startActivity(

17
src/libutil/strings.cc
View file

@ -8,23 +8,6 @@
namespace nix {
struct view_stringbuf : public std::stringbuf
{
inline std::string_view toView()
{
auto begin = pbase();
return {begin, begin + pubseekoff(0, std::ios_base::cur, std::ios_base::out)};
}
};
__attribute__((no_sanitize("undefined"))) std::string_view toView(const std::ostringstream & os)
{
/* Downcasting like this is very much undefined behavior, so we disable
UBSAN for this function. */
auto buf = static_cast<view_stringbuf *>(os.rdbuf());
return buf->toView();
}
template std::list<std::string> tokenizeString(std::string_view s, std::string_view separators);
template StringSet tokenizeString(std::string_view s, std::string_view separators);
template std::vector<std::string> tokenizeString(std::string_view s, std::string_view separators);