Commit cfe66dbec updated `nix upgrade-nix` to use
`ExecutablePath::load().find`, which broke the logic for finding the
profile associated with the nix executable. The error looks something
like:
```
$ sudo -i nix upgrade-nix --debug
found Nix in '"/nix/store/46p1z0w9ad605kky62dr53z4h24k2a5r-nix-2.25.2/bin/nix"'
found profile '/nix/store/46p1z0w9ad605kky62dr53z4h24k2a5r-nix-2.25.2/bin'
error: directory '"/nix/store/46p1z0w9ad605kky62dr53z4h24k2a5r-nix-2.25.2/bin/nix"' does not appear to be part of a Nix profile
```
This seems to happen for two reasons:
1. The original PATH search resulted in a directory, but `find` returns
the path to the executable. Fixed by getting the path's parent.
2. The profile symlink cannot be found because
`ExecutablePath::load().find` canonicalizes the executable path. I
updated find to normalize the path instead, which seems more in line
with how other programs resolve paths. I'm not sure if this affects
other callers though.
I manually tested this on macOS and Linux, and it seemed to fix
upgrading from 2.25.2 to 2.25.3.
Fix a footgun. In my case, I had a couple of build ("output")
directories sitting around.
rm -rf build-*
Was confused for a bit why a meson.build file was missing.
Probably also helps with autocompletion.
I tried meson-build-support first, but I had to add something like
a nix- prefix, in order to make meson happy. They've reserved the
meson- prefix.
Before this change, expressions like:
with import <nixpkgs> {};
runCommand "foo" {} ''
echo '@nix {}' >&$NIX_LOG_FD
''
would result in Lix crashing, because accessing nonexistent fields of
a JSON object throws an exception.
Rather than handling each field individually, we just catch JSON
exceptions wholesale. Since these log messages are an unusual
circumstance, log a warning when this happens.
Fixes#544.
Change-Id: Idc2d8acf6e37046b3ec212f42e29269163dca893
(cherry picked from commit e55cd3beea710db727fd966f265a1b715b7285f3)
This prevents any potential cases of deletion through base pointer and its
non-virtual dtor, which might leak memory. Also gets rid of the warning:
/nix/store/fg7ass3a5m5pgl26qzfdniicbwbgzccy-gcc-13.2.0/include/c++/13.2.0/bits/stl_construct.h:88:2: warning: destructor called on non-final 'nix::flake::Settings' that has virtual functions but non-virtual destructor [-Wdelete-non-abstract-non-virtual-dtor]
88 | __location->~_Tp();
....
../src/libflake-c/nix_api_flake.cc:10:30: note: in instantiation of function template specialization 'nix::make_ref<nix::flake::Settings>' requested here
10 | auto settings = nix::make_ref<nix::flake::Settings>();
This gets rid of unnecessary copies in range-based-for loops and
local variables, when they are used solely as `const &`.
Also added a fixme comment about a suspicious move out of const,
which might not be intended.
Looks like some cruft has been left over from previous refactorings.
This removes dead variables, which should not have side effects in their
constructors. In cases where the variable initialization has a purpose
[[maybe_unused]] is inserted to silence compiler warnings.
This reduces the amount of boilerplate. More importantly, it provides
a place to add compiler flags (such as -O3) without having to add it
to every subproject (and the risk of forgetting to include it).
In these trivial cases the final vector size (or lower bound on the size) is known,
so we can avoid some vector reallocations. This is not very important, but is just
good practice and general hygiene.
This is good practice to avoid pessimisations.
Left comments for the reasoning why ctors should be noexcept.
There are some tricky cases where we intentionally want throwing move ctors/assignments.
But those cases should really be reviewed, since some of those can be replaced
with more idiomatic copy/move-and-swap.
`auto &&` and `T &&` are forwarding references and can be
either lvalue or rvalue references. Moving from universal references
is incorrect and should not be done.
Moving from integral or floating-point values is pointless and just
worsens debug performance.
Naming class member variables the same as constructor arguments is a very
slippery slope because of how member variable names get resolved. Compiler
is not very helpful here and we need static analysis to forbid this kind of
stuff.
The following example illustrates the cause quite well:
```cpp
struct B {
B(int) {}
};
struct A {
A(int b): b([&](){
return b;
static_assert(std::is_same_v<decltype(b), int>);
}()) {
static_assert(std::is_same_v<decltype(b), int>);
}
void member() {
static_assert(std::is_same_v<decltype(b), B>);
}
B b;
};
int main() {
A(1).member();
}
```
From N4861 6.5.1 Unqualified name lookup:
> In all the cases listed in [basic.lookup.unqual], the scopes are searched
> for a declaration in the order listed in each of the respective categories;
> name lookup ends as soon as a declaration is found for the name.
> If no declaration is found, the program is ill-formed.
In the affected code there was a use-after-move for all accesses in the constructor
body, but this UB wasn't triggered.
These types of errors are trivial to catch via clang-tidy's [clang-analyzer-cplusplus.Move].
Unfortunately `StringSource` class is very easy was very easy to misuse
because the ctor took a plain `std::string_view` which has a bad habit
of being implicitly convertible from an rvalue `std::string`. This lead
to unintentional use-after-free bugs.
This patch makes `StringSource` much harder to misuse by disabling the ctor
from a `std::string &&` (but `const std::string &` is ok).
Fix affected tests from libstore-tests.
Reformat those tests with clangd's range formatting since the diff is tiny
and it seems appropriate.
