the default int64_t max was still overflowing for me, when this was dumped as json (noticed during building the manual).
So making 0, the default and define it as "no warnings" fixes the situtation.
Also it's much more human-readable in documentation.
This is because with the split packages of the Meson build, we simply
have no idea what directory the binaries will be installed in when we
build the library.
In the process of doing so, consolidate and make more sophisticated the
logic to cope with a few corner cases (e.g. `NIX_BIN_DIR` exists, but no
binaries are inside it).
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
This also bans various sneaking of negative numbers from the language
into unsuspecting builtins as was exposed while auditing the
consequences of changing the Nix language integer type to a newtype.
It's unlikely that this change comprehensively ensures correctness when
passing integers out of the Nix language and we should probably add a
checked-narrowing function or something similar, but that's out of scope
for the immediate change.
During the development of this I found a few fun facts about the
language:
- You could overflow integers by converting from unsigned JSON values.
- You could overflow unsigned integers by converting negative numbers
into them when going into Nix config, into fetchTree, and into flake
inputs.
The flake inputs and Nix config cannot actually be tested properly
since they both ban thunks, however, we put in checks anyway because
it's possible these could somehow be used to do such shenanigans some
other way.
Note that Lix has banned Nix language integer overflows since the very
first public beta, but threw a SIGILL about them because we run with
-fsanitize=signed-overflow -fsanitize-undefined-trap-on-error in
production builds. Since the Nix language uses signed integers, overflow
was simply undefined behaviour, and since we defined that to trap, it
did.
Trapping on it was a bad UX, but we didn't even entirely notice
that we had done this at all until it was reported as a bug a couple of
months later (which is, to be fair, that flag working as intended), and
it's got enough production time that, aside from code that is IMHO buggy
(and which is, in any case, not in nixpkgs) such as
https://git.lix.systems/lix-project/lix/issues/445, we don't think
anyone doing anything reasonable actually depends on wrapping overflow.
Even for weird use cases such as doing funny bit crimes, it doesn't make
sense IMO to have wrapping behaviour, since two's complement arithmetic
overflow behaviour is so *aggressively* not what you want for *any* kind
of mathematics/algorithms. The Nix language exists for package
management, a domain where bit crimes are already only dubiously in
scope to begin with, and it makes a lot more sense for that domain for
the integers to never lose precision, either by throwing errors if they
would, or by being arbitrary-precision.
Fixes: https://github.com/NixOS/nix/issues/10968
Original-CL: https://gerrit.lix.systems/c/lix/+/1596
Change-Id: I51f253840c4af2ea5422b8a420aa5fafbf8fae75
* 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.
They are not actually part of the store layer, but instead part of the
Nix executable infra (libraries don't need plugins, executables do).
This is part of a larger project of moving all of our legacy settings
infra to libmain, and having the underlying libraries just have plain
configuration structs detached from any settings infra / UI layer.
Progress on #5638
In addition:
- Take the opportunity to add a bunch more missing hyperlinks, too.
- Remove some glossary entries that are now subsumed by dedicated pages.
We used to not be able to do this without breaking link fragments, but
now we can, so pick up where we left off.
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
This is useful for diagnosing whether an evaluation is copying large
paths to the store. Example:
$ nix build .#packages.x86_64-linux.default --large-path-warning-threshold 1000000
warning: copied large path '/home/eelco/Dev/nix-master/' to the store (6271792 bytes)
warning: copied large path '«github:NixOS/nixpkgs/b550fe4b4776908ac2a861124307045f8e717c8e?narHash=sha256-7kkJQd4rZ%2BvFrzWu8sTRtta5D1kBG0LSRYAfhtmMlSo%3D»/' to the store (155263768 bytes)
warning: copied large path '«github:libgit2/libgit2/45fd9ed7ae1a9b74b957ef4f337bc3c8b3df01b5?narHash=sha256-oX4Z3S9WtJlwvj0uH9HlYcWv%2Bx1hqp8mhXl7HsLu2f0%3D»/' to the store (22175416 bytes)
warning: copied large path '/nix/store/z985088mcd6w23qwdlirsinnyzayagki-source' to the store (5885872 bytes)
At this point many features are stripped out, but this works:
- Can run libnix{util,store,expr} unit tests
- Can run some Nix commands
Co-Authored-By volth <volth@volth.com>
Co-Authored-By Brian McKenna <brian@brianmckenna.org>
"hash type" -> "hash algorithm" in all comments, documentation, and
messages.
ht -> ha, [Hh]ashType -> [HhashAlgo] for all local variables and
function arguments. No API change is made.
Continuation of 5334c9c792 and 837b889c41.
* reword description of the `cores` setting
- be precise about the `builder` executable
- clearly distinguish between `builder` and job parallelism
- clarify the role of `mkDerivation` in the example
- remove prose for the default, it's shown programmatically
- mention relation to `max-jobs`
- move all reference documentation to the `builders` configuration setting
- reword documentation on machine specification, add examples
- disable showing the default value, as it rendered as `@/dummy/machines`, which is wrong
- highlight the examples
- link to the configuration docs for distributed builds
- builder -> build machine
Co-authored-by: Janik H <janik@aq0.de>
Good to document these formats separately from commands that happen to
use them.
Eventually I would like this and `builtins.derivation` to refer to a
store section on derivations that is authoritative, but that doesn't yet
exist, and will take some time to make. So I think we're just best off
merging this now as is.
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
`eval-system` option overrides just the value of `builtins.currentSystem`.
This is more useful than overriding `system` since you can build these
derivations on remote builders which can work on the given system.
Co-authored-by: John Ericson <John.Ericson@Obsidian.Systems>
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
- remove prose for the default value, which is shown programmatically
- add note on how this relates to `cores`
- add link to mentioned derivation attribute
This makes for more useful manual table of contents, that displays the
information at a glance.
The `nix help-stores` command is kept as-is, even though it will show up
in the manual with the same information as these pages due to the way it
is written as a "`--help`-style" command. Deciding what to do with that
command is left for a later PR.
This change also lists all store types at the top of the respective overview page.
Co-authored-by: John Ericson <John.Ericson@Obsidian.Systems
All OS and IO operations should be moved out, leaving only some misc
portable pure functions.
This is useful to avoid copious CPP when doing things like Windows and
Emscripten ports.
Newly exposed functions to break cycles:
- `restoreSignals`
- `updateWindowSize`
Add a new experimental `impure-env` setting that is a key-value list of
environment variables to inject into FOD derivations that specify the
corresponding `impureEnvVars`.
This allows clients to make use of this feature (without having to change the
environment of the daemon itself) and might eventually deprecate the current
behaviour (pick whatever is in the environment of the daemon) as it's more
principled and might prevent information leakage.
