keeping it as a simple data member means it won't be scanned by the GC, so
eventually the GC will collect a cache that is still referenced (resulting in
use-after-free of cache elements).
fixes#5962
If we want to be careful about hitting the stack protector page, we should use `-fstack-check` instead.
Co-authored-by: Eelco Dolstra <edolstra@gmail.com>
This no longer worked correctly because 'path' is uninitialised when
an exception occurs, leading to errors like
… while importing ''
at /nix/store/rrzz5b1pshvzh1437ac9nkl06br81lkv-source/flake.nix:352:13:
So move the adding of the error context into realisePath().
This was removed in 2e199673a5 when
`copyPath` transitioned to use `RealisedPath`. But then in
e9848beca7 we added it back just for
`realisedPath`.
I think it is a good utility function --- one can easily imagine it
becoming optimized in the future, and copying paths *violating* the
closure is a very niche feature.
So if we have `copyPaths` for both sorts of paths, I think we should
have `copyClosure` for both sorts too.
This removes a dynamic stack allocation, making the derivation
unparsing logic robust against overflows when large strings are
added to a derivation.
Overflow behavior depends on the platform and stack configuration.
For instance, x86_64-linux/glibc behaves as (somewhat) expected:
$ (ulimit -s 20000; nix-instantiate tests/lang/eval-okay-big-derivation-attr.nix)
error: stack overflow (possible infinite recursion)
$ (ulimit -s 40000; nix-instantiate tests/lang/eval-okay-big-derivation-attr.nix)
error: expression does not evaluate to a derivation (or a set or list of those)
However, on aarch64-darwin:
$ nix-instantiate big-attr.nix ~
zsh: segmentation fault nix-instantiate big-attr.nix
This indicates a slight flaw in the single stack protection page
approach that is not encountered with normal stack frames.
Unless `--precise` is passed, make `nix why-depends` only show the
dependencies between the store paths, without introspecting them to
find the actual references.
This also makes it ~3x faster
This is needed to get the path of a derivation that might not exist
(e.g. for 'nix store copy-log').
InstallableStorePath::toDerivedPaths() cannot be used for this because
it calls readDerivation(), so it fails if the store doesn't have the
derivation.
