Prior to this change, Nix would prepend every installable to the PATH
list in order to ensure that installables appeared before the current
PATH from the ambient environment.
With this change, all the installables are still prepended to the PATH,
but in the same order as they appear on the command line. This means
that the first of two packages that expose an executable `hello` would
appear in the PATH first, and thus be executed first.
See the test in the prior commit for a more concrete example.
There's no good reason to deprecate it:
- For consistency reasons it should continue to exist, such that all
primitive types have a corresponding `builtins.is*` primop.
- There's no implementation cost to continuing to have this function
- It costs users time to try to migrate away from it, e.g.
https://github.com/NixOS/nixpkgs/pull/219747 and https://github.com/NixOS/nixpkgs/pull/275548
- Using it can give easier-to-read code like `all isNull list`
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
this also reduces forceValue code size and removes the need for
hideInDiagnostics. coopting thunk forcing like this has the additional
benefit of clarifying how these errors can happen in the first place.
forceValue is extremely hot. interestingly adding likeliness annotations
to the branches does not seem to make a difference.
before:
Time (mean ± σ): 4.224 s ± 0.005 s [User: 3.711 s, System: 0.512 s]
Range (min … max): 4.218 s … 4.234 s 10 runs
after:
Time (mean ± σ): 4.140 s ± 0.009 s [User: 3.647 s, System: 0.492 s]
Range (min … max): 4.130 s … 4.152 s 10 runs
almost all uses of this are interactive, except for deepSeq. deepSeq is
going to be expensive and rare enough to not care much about, and
Value::determinePos should usually be cheap enough to not be too much of
a burden in any case.
~1% parser speedup from not using TLS indirections, less on system eval.
this could have also gone in flex yyextra data, but that's significantly
slower for some reason (albeit still faster than thread locals).
before:
Time (mean ± σ): 4.231 s ± 0.004 s [User: 3.725 s, System: 0.504 s]
Range (min … max): 4.226 s … 4.240 s 10 runs
after:
Time (mean ± σ): 4.224 s ± 0.005 s [User: 3.711 s, System: 0.512 s]
Range (min … max): 4.218 s … 4.234 s 10 runs
~2% speedup on parsing without eval, less (but still significant) on
system eval. having flex generate faster parsers leads to very strange
misparses. maybe re2c is worth investigating.
before:
Time (mean ± σ): 4.260 s ± 0.003 s [User: 3.754 s, System: 0.505 s]
Range (min … max): 4.257 s … 4.266 s 10 runs
after:
Time (mean ± σ): 4.231 s ± 0.004 s [User: 3.725 s, System: 0.504 s]
Range (min … max): 4.226 s … 4.240 s 10 runs
as written the comparisons generate copies, even though it looks as
though they shouldn't.
before:
Time (mean ± σ): 4.396 s ± 0.002 s [User: 3.894 s, System: 0.501 s]
Range (min … max): 4.393 s … 4.399 s 10 runs
after:
Time (mean ± σ): 4.260 s ± 0.003 s [User: 3.754 s, System: 0.505 s]
Range (min … max): 4.257 s … 4.266 s 10 runs
checking for isBlackhole in the forceValue hot path is rather more
expensive than necessary, and with a little bit of trickery we can move
such handling into the isApp case. small performance benefit, but under
some circumstances we've seen 2% improvement as well.
〉 nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
before:
Time (mean ± σ): 4.429 s ± 0.002 s [User: 3.929 s, System: 0.500 s]
Range (min … max): 4.427 s … 4.433 s 10 runs
after:
Time (mean ± σ): 4.396 s ± 0.002 s [User: 3.894 s, System: 0.501 s]
Range (min … max): 4.393 s … 4.399 s 10 runs
resizing a std::string clears the newly added bytes, which is not
necessary here and comes with a ~1.4% slowdown on our test nixos config.
〉 nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
before:
Time (mean ± σ): 4.486 s ± 0.003 s [User: 3.978 s, System: 0.507 s]
Range (min … max): 4.482 s … 4.492 s 10 runs
after:
Time (mean ± σ): 4.429 s ± 0.002 s [User: 3.929 s, System: 0.500 s]
Range (min … max): 4.427 s … 4.433 s 10 runs
This keeps hint messages, source location information, and source code
snippets grouped together, while making stack traces shorter (so that
more stack frames can be viewed on the same terminal).
Before:
error:
… while evaluating the attribute 'body'
at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:4:3:
3|
4| body = x "x";
| ^
5| }
… from call site
at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:4:10:
3|
4| body = x "x";
| ^
5| }
… while calling 'x'
at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:2:7:
1| let {
2| x = arg: assert arg == "y"; 123;
| ^
3|
error: assertion '(arg == "y")' failed
at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:2:12:
1| let {
2| x = arg: assert arg == "y"; 123;
| ^
3|
After:
error:
… while evaluating the attribute 'body'
at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:4:3:
3|
4| body = x "x";
| ^
5| }
… from call site
at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:4:10:
3|
4| body = x "x";
| ^
5| }
… while calling 'x'
at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:2:7:
1| let {
2| x = arg: assert arg == "y"; 123;
| ^
3|
error: assertion '(arg == "y")' failed
at /Users/wiggles/nix/tests/functional/lang/eval-fail-assert.nix:2:12:
1| let {
2| x = arg: assert arg == "y"; 123;
| ^
3|
`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>
I wrote the `configure.ac` wrong, and so we just got no builds
supporting ACLs.
Also, it needs to be more precise because Darwin puts other stuff in
that same header, evidently.
I don't love the way this code looks. There are two larger problems:
- eval, build/scratch, destination stores (#5025) should have different
types to reflect the fact that they are used for different purposes
and those purposes correspond to different operations. It should be
impossible to "use the wrong store" in my cases.
- Since drvs can end up in both the eval and build/scratch store, we
should have some sort of union/layered store (not on the file sytem
level, just conceptual level) that allows accessing both. This would
get rid of the ugly "check both" boilerplate in this PR.
Still, it might be better to land this now / soon after minimal cleanup,
so we have a concrete idea of what problem better abstractions are
supposed to solve.
Below the comment added by this commit is a much longer comment
followed by a trust check, both of which have confused me on at
least two occasions. I figured it out once, forgot it, then had to
ask @Ericson2314 to explain it, at which point I understood it
again. I think this might confuse other people too, or maybe I will
just forget it a third time. So let's add a comment.
Farther down in the function is the following check:
```
if (!(drvType.isCA() || trusted))
throw Error("you are not privileged to build input-addressed derivations");
```
This seems really strange at first. A key property of Nix is that
you can compute the outpath of a derivation using the derivation
(and its references-closure) without trusting anybody!
The missing insight is that at this point in the code the builder
doesn't necessarily have the references-closure of the derivation
being built, and therefore needs to trust that the derivation's
outPath is honest. It's incredibly easy to overlook this, because
the only difference between these two cases is which of these
identically-named functions we used:
- `readDerivation(Source,Store)`
- `Store::readDerivation()`
These functions have different trust models (except in the special
case where the first function is used on the local store). We
should call the reader's attention to this fact.
Co-authored-by: Cole Helbling <cole.e.helbling@outlook.com>
In https://github.com/NixOS/nix/pull/6134#issuecomment-1079199888,
@thuffschmitt proposed exposing `LegacySSHStore` in Nix for
deduplication with Hydra, at least temporarily. I think that is a good
idea.
Note that the diff will look bad unless one ignores whitespace! Also try
this locally:
```shell-session
git diff --ignore-all-space HEAD^:src/libstore/legacy-ssh-store.cc HEAD:src/libstore/legacy-ssh-store.cc
git diff --ignore-all-space HEAD^:src/libstore/legacy-ssh-store.cc HEAD:src/libstore/legacy-ssh-store.hh
```
* document `fetchTree`
* display experimental feature note at the top
we have to enable the new `fetchTree` experimental feature to render it
at all. this was a bug introduced when adding that new feature flag.
Co-authored-by: tomberek <tomberek@users.noreply.github.com>
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
Co-authored-by: Silvan Mosberger <github@infinisil.com>
The code has already been fixed (yay!) so what is left of this commit is
just updating the API docs.
Co-authored-by: Cole Helbling <cole.e.helbling@outlook.com>
According https://en.cppreference.com/w/cpp/io/strstream, it has been
deprecated since C++98! The Clang + Linux build systems to not have it
at all, or at least be hiding it.
We can just use `std::stringstream` instead, I think.
* Print the value in `error: cannot coerce` messages
This extends the `error: cannot coerce a TYPE to a string` message
to print the value that could not be coerced. This helps with debugging
by making it easier to track down where the value is being produced
from, especially in errors with deep or unhelpful stack traces.
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
This is needed for building CA deriations with a src store / dest store
split. In particular it is needed for Hydra.
https://github.com/NixOS/hydra/issues/838 currently puts realizations,
and thus build outputs, in the local store, but it should not.
This includes position information in more places, making debugging
easier.
Before:
```
$ nix-instantiate --show-trace --eval tests/functional/lang/eval-fail-using-set-as-attr-name.nix
error:
… while evaluating an attribute name
at «none»:0: (source not available)
error: value is a set while a string was expected
```
After:
```
error:
… while evaluating an attribute name
at /pwd/lang/eval-fail-using-set-as-attr-name.nix:5:10:
4| in
5| attr.${key}
| ^
6|
error: value is a set while a string was expected
```
In the process, partially undo e89b5bd0bf
in that the ancient < 2.4 version is now supported again by the
serializer again. `LegacySSHStore`, instead of also asserting that the
version is at least 4, just checks that `narHash` is set.
This allows us to better test the serializer in isolation for both
versions (< 4 and >= 4).
AppleDouble files were extracted differently on macOS machines than on other
UNIX's.
Setting `archive_read_set_format_option(this->archive, NULL ,"mac-ext",NULL)`
fixes this problem, since it just ignores the AppleDouble file and treats it as
a normal one.
This was a problem since it caused source archives to be different between macOS
and Linux.
Ref: nixos/nix#9290
* Factor out the default `MultiCommand` behavior
All the `MultiCommand`s had (nearly) the same behavior when called
without a subcommand.
Factor out this behavior into the `NixMultiCommand` class.
* Display the list of available subcommands when none is specified
Whenever a user runs a command that excepts a subcommand, add the list
of available subcommands to the error message.
* Print the multi-command lists as Markdown lists
This takes more screen real estate, but is also much more readable than
a comma-separated list
without knowing a lot of context, it's not clear who "we" are in that
text. I'm also strongly opposed to adding procedural notes into
a reference manual; it just won't age well.
this change leaves a factual description of the experimental feature and
its purpose.
Today, with the tests inside a `tests` intermingled with the
corresponding library's source code, we have a few problems:
- We have to be careful that wildcards don't end up with tests being
built as part of Nix proper, or test headers being installed as part
of Nix proper.
- Tests in libraries but not executables is not right:
- It means each executable runs the previous unit tests again, because
it needs the libraries.
- It doesn't work right on Windows, which doesn't want you to load a
DLL just for the side global variable . It could be made to work
with the dlopen equivalent, but that's gross!
This reorg solves these problems.
There is a remaining problem which is that sibbling headers (like
`hash.hh` the test header vs `hash.hh` the main `libnixutil` header) end
up shadowing each other. This PR doesn't solve that. That is left as
future work for a future PR.
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
