Before this change, stdout was closed after the pager exits. This is
fine for non-interactive commands where we want to exit right after
the pager exits anyways, but for interactive things (e.g. nix repl)
this breaks the output after we quit the pager.
Keep the initial stdout fd as part of RunPager, and restore it in
RunPager::~RunPager using dup2.
This avoids an ambiguity where the `StorePathWithOutputs { drvPath, {}
}` could mean "build `brvPath`" or "substitute `drvPath`" depending on
context.
It also brings the internals closer in line to the new CLI, by
generalizing the `Buildable` type is used there and makes that
distinction already.
In doing so, relegate `StorePathWithOutputs` to being a type just for
backwards compatibility (CLI and RPC).
Most functions now take a StorePath argument rather than a Path (which
is just an alias for std::string). The StorePath constructor ensures
that the path is syntactically correct (i.e. it looks like
<store-dir>/<base32-hash>-<name>). Similarly, functions like
buildPaths() now take a StorePathWithOutputs, rather than abusing Path
by adding a '!<outputs>' suffix.
Note that the StorePath type is implemented in Rust. This involves
some hackery to allow Rust values to be used directly in C++, via a
helper type whose destructor calls the Rust type's drop()
function. The main issue is the dynamic nature of C++ move semantics:
after we have moved a Rust value, we should not call the drop function
on the original value. So when we move a value, we set the original
value to bitwise zero, and the destructor only calls drop() if the
value is not bitwise zero. This should be sufficient for most types.
Also lots of minor cleanups to the C++ API to make it more modern
(e.g. using std::optional and std::string_view in some places).
Also, move a few free-standing functions into StoreAPI and Derivation.
Also, introduce a non-nullable smart pointer, ref<T>, which is just a
wrapper around std::shared_ptr ensuring that the pointer is never
null. (For reference-counted values, this is better than passing a
"T&", because the latter doesn't maintain the refcount. Usually, the
caller will have a shared_ptr keeping the value alive, but that's not
always the case, e.g., when passing a reference to a std::thread via
std::bind.)
This flag causes paths that do not have a known substitute to be
quietly ignored. This is mostly useful for Charon, allowing it to
speed up deployment by letting a machine use substitutes for all
substitutable paths, instead of uploading them. The latter is
frequently faster, e.g. if the target machine has a fast Internet
connection while the source machine is on a slow ADSL line.
I.e. do what git does. I'm too lazy to keep the builtin help text up
to date :-)
Also add ‘--help’ to various commands that lacked it
(e.g. nix-collect-garbage).
Output names are now appended to resulting GC symlinks, e.g. by
nix-build. For backwards compatibility, if the output is named "out",
nothing is appended. E.g. doing "nix-build -A foo" on a derivation
that produces outputs "out", "bin" and "dev" will produce symlinks
"./result", "./result-bin" and "./result-dev", respectively.
By moving the destructor object to libstore.so, it's also run when
download-using-manifests and nix-prefetch-url exit. This prevents
them from cluttering /nix/var/nix/temproots with stale files.
the contents of any of the given store paths have been modified.
E.g.
$ nix-store --verify-path $(nix-store -qR /var/run/current-system)
path `/nix/store/m2smyiwbxidlprfxfz4rjlvz2c3mg58y-etc' was modified! expected hash `fc87e271c5fdf179b47939b08ad13440493805584b35e3014109d04d8436e7b8', got `20f1a47281b3c0cbe299ce47ad5ca7340b20ab34246426915fce0ee9116483aa'
All paths are checked; the exit code is 1 if any path has been
modified, 0 otherwise.
This should also fix:
nix-instantiate: ./../boost/shared_ptr.hpp:254: T* boost::shared_ptr<T>::operator->() const [with T = nix::StoreAPI]: Assertion `px != 0' failed.
which was caused by hashDerivationModulo() calling the ‘store’
object (during store upgrades) before openStore() assigned it.
bytes have been freed, `--max-links' to stop when the Nix store
directory has fewer than N hard links (the latter being important
for very large Nix stores on filesystems with a 32000 subdirectories
limit).
via the Unix domain socket in /nix/var/nix/daemon.socket. The
server forks a worker process per connection.
* readString(): use the heap, not the stack.
* Some protocol fixes.
