Since lib{expr,store,util}-test-support subprojects define nix_api_* helpers
for testing nix c bindings, they need to publicly depend on -c counterparts.
This makes their headers self-sufficient and does not rely on the -tests to add
necessary dependencies.
Get rid of this fixme. This does not appear to be used anywhere in
the nix codebase itself. Not sure why the comment mentioned C++20 erase
member function with predicate, but iterator-based algorithms are also fine.
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.
* doc: Clarify that nix-shell still uses shell from host environment
* doc: Fix NIX_BUILD_SHELL description
* doc: Add anchor and link to NIX_BUILD_SHELL
* doc: Add example of default shell trickiness
Co-authored-by: Valentin Gagarin <valentin@gagarin.work>
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).
Fixes
nix: ../src/libexpr/primops/fetchTree.cc:37: void nix::emitTreeAttrs(EvalState&, const StorePath&, const fetchers::Input&, Value&, bool, bool): Assertion `narHash' failed.
on a lock file with an input that doesn't have a narHash. This can
happen when using a lock file created by the lazy-trees branch.
Cherry-picked from lazy-trees.
When diagnosing infinite recursion references to nullptr `Env` can be formed.
This happens only with `ExprBlackHole` is evaluated, which always leads to
`InfiniteRecursionError`.
UBSAN log for one such case:
```
../src/libexpr/eval-inline.hh:94:31: runtime error: reference binding to null pointer of type 'Env'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../src/libexpr/eval-inline.hh:94:31 in
```
First the motivation: I recently faced a bug that I assume is coming
from the topoSortPaths function where the GC was trying to delete a
path having some alive referrers. I resolved this by manually deleting
the faulty path referrers using nix-store --query --referrers. I sadly
did not manage to reproduce this bug.
This bug alone is not a big deal. However, this bug is
triggering a cascading failure: invalidatePathChecked is throwing a
PathInUse exception. This exception is not catched and fails the whole GC
run. From there, the machine (a builder machine) was unable to GC its
Nix store, which led to an almost full disk with no way to
automatically delete the dead Nix paths.
Instead, I think we should log the error for the specific store path
we're trying to delete, specifying we can't delete this path because
it still has referrers. Once we're done with logging that, the GC run
should continue to delete the dead store paths it can delete.
This is the first part of rewriteDerivation() factored out into its
own method. It's not used anywhere else at the moment, but it's useful
on lazy-trees for rewriting virtual paths.
