This was done originally because std::smatch does not accept `const char
*` as iterators. However, this was because we should have been using
std::cmatch instead.
(cherry picked from commit 12a5838d11)
Found by looking for interesting asan reports from the test suite.
What happened here is that name got overwritten, but it was what
actually held the backing memory for the thing it got overwritten by,
which was a by-reference value coming out of std::regex.
Due to absurd reasons I cannot seem to use a string_view iterator here,
so I just copy the string with a longer lifetime instead. idk lol
==3796364==ERROR: AddressSanitizer: heap-use-after-free on address 0x503000014c61 at pc 0x74843523bf1d bp 0x7ffc68351330 sp 0x7ffc68350af0
READ of size 3 at 0x503000014c61 thread T0
0 0x74843523bf1c in __asan_memcpy (/nix/store/mzhqknx2mc94jdz4n320hn1lml86398y-clang-wrapper-17.0.6/resource-root/lib/linux/libclang_rt.asan-x86_64.so+0x159f1c)
1 0x6403cf6cbff4 in std::char_traits<char>::copy(char*, char const*, unsigned long) /nix/store/14c6s4xzhy14i2b05s00rjns2j93gzz4-gcc-13.2.0/include/c++/13.2.0/bits/char_traits.h:445:33
<...>
7 0x6403cf6cbff4 in std::__cxx11::sub_match<__gnu_cxx::__normal_iterator<char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>>>::str() const /nix/store/14c6s4xzhy14i2b05s00rjns2j93gzz4-gcc-13.2.0/include/c++/13.2.0/bits/regex.h:966:6
8 0x6403cf6cbff4 in std::__cxx11::sub_match<__gnu_cxx::__normal_iterator<char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>>>::operator std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>() const /nix/store/14c6s4xzhy14i2b05s00rjns2j93gzz4-gcc-13.2.0/include/c++/13.2.0/bits/regex.h:955:16
9 0x6403cf6cbff4 in nix::getClosureInfo[abi:cxx11](nix::ref<nix::Store>, nix::StorePath const&) /home/jade/lix/lix2/build/src/nix/diff-closures.cc:37:26
10 0x6403cf6cd70c in nix::printClosureDiff(nix::ref<nix::Store>, nix::StorePath const&, nix::StorePath const&, std::basic_string_view<char, std::char_traits<char>>) /home/jade/lix/lix2/build/src/nix/diff-closures.cc:54:25
11 0x6403cf873331 in CmdProfileDiffClosures::run(nix::ref<nix::Store>) /home/jade/lix/lix2/build/src/nix/profile.cc:479:17
<...>
0x503000014c61 is located 17 bytes inside of 21-byte region [0x503000014c50,0x503000014c65)
freed by thread T0 here:
0 0x748435250470 in operator delete(void*) (/nix/store/mzhqknx2mc94jdz4n320hn1lml86398y-clang-wrapper-17.0.6/resource-root/lib/linux/libclang_rt.asan-x86_64.so+0x16e470)
<...>
6 0x6403cf6cbda2 in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>::~basic_string() /nix/store/14c6s4xzhy14i2b05s00rjns2j93gzz4-gcc-13.2.0/include/c++/13.2.0/bits/basic_string.h:792:9
7 0x6403cf6cbda2 in nix::getClosureInfo[abi:cxx11](nix::ref<nix::Store>, nix::StorePath const&) /home/jade/lix/lix2/build/src/nix/diff-closures.cc:36:13
8 0x6403cf6cd70c in nix::printClosureDiff(nix::ref<nix::Store>, nix::StorePath const&, nix::StorePath const&, std::basic_string_view<char, std::char_traits<char>>) /home/jade/lix/lix2/build/src/nix/diff-closures.cc:54:25
<...>
previously allocated by thread T0 here:
0 0x74843524fa38 in operator new(unsigned long) (/nix/store/mzhqknx2mc94jdz4n320hn1lml86398y-clang-wrapper-17.0.6/resource-root/lib/linux/libclang_rt.asan-x86_64.so+0x16da38)
<...>
9 0x6403cf6cb68c in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>::basic_string<std::basic_string_view<char, std::char_traits<char>>, void>(std::basic_string_view<char, std::char_traits<char>> const&, std::allocator<char> const&) /nix/store/14c6s4xzhy14i2b05s00rjns2j93gzz4-gcc-13.2.0/include/c++/13.2.0/bits/basic_string.h:784:4
10 0x6403cf6cb68c in nix::getClosureInfo[abi:cxx11](nix::ref<nix::Store>, nix::StorePath const&) /home/jade/lix/lix2/build/src/nix/diff-closures.cc:33:21
11 0x6403cf6cd70c in nix::printClosureDiff(nix::ref<nix::Store>, nix::StorePath const&, nix::StorePath const&, std::basic_string_view<char, std::char_traits<char>>) /home/jade/lix/lix2/build/src/nix/diff-closures.cc:54:25
12 0x6403cf873331 in CmdProfileDiffClosures::run(nix::ref<nix::Store>) /home/jade/lix/lix2/build/src/nix/profile.cc:479:17
<...>
(cherry-picked from b9b1bbd22f)
We should use a metric that weighs the related issues.
Counterbalancing time doesn't make much sense to me.
If it's around for longer, the fix will be relevant to more people.
* manual: Contributing -> Development, Hacking -> Building
what's currently called "hacking" are really instructions for setting up
a development environment and compiling from source. we have
a contribution guide in the repo (which rightly focuses on GitHub
workflows), and the material in the manual is more about working
on the code itself.
since we'd otherwise have three headings that amount to "Building Nix",
this change also moves the "classic Nix" instructions to the top.
we may want to reorganise this in the future, and bring
contributor-oriented information closer to the code, but for now let's
stick to more accurate names to ease navigation.
Meson uses a venerable GNU convention described in
https://www.gnu.org/software/automake/manual/html_node/Scripts_002dbased-Testsuites.html
in which:
> When no test protocol is in use, an exit status of 0 from a test
> script will denote a success, an exit status of 77 a skipped test, an
> exit status of 99 a hard error, and any other exit status will denote
> a failure.
77 is thus what we want, not 99.
* fix NIX_PATH overriding
- test restricted evaluation
- test precedence for setting the search path
Co-authored-by: Robert Hensing <robert@roberthensing.nl>
Co-authored-by: John Ericson <git@JohnEricson.me>
We are piping curl downloads into `unpackTarfileToSink()`, but the
latter is typically slower than the former if you're on a fast
connection. So the download could appear unnecessarily slow. (There is
even a risk that if the Git import is *really* slow for whatever
reason, the TCP connection could time out.)
So let's make the download buffer bigger by default - 64 MiB is big
enough for the Nixpkgs tarball. Perhaps in the future, we could have
an unlimited buffer that spills data to disk beyond a certain
threshold, but that's probably overkill.
