Commit 05f42519b5 fixed b/281 by
establishing a hygiene regimen to partition *catchable* errors
(i.e. those which tryEval can detect) from all other errors, like
internal VM failures or I/O errors (which Nix must not be allowed to
detect, since these errors are fundamentally impure).
Unfotunately there are still cases where tvix assumes that anything
other than Value::Bool means it should panic!(). I found another
one, and added a test case for it in:
eval_okay_src_tests_tvix_tests_eval_okay_compare_ordering_catchable_nix
Not yet passing.
Change-Id: I69c62ed9ea5c8f81870e8de5c5fe12dcde849763
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10220
Autosubmit: Adam Joseph <adam@westernsemico.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This commit rewrites Value::nix_cmp_ordering() into an equivalent
nonrecursive form. Except for calls to Thunk::force(), the new form
no longer uses generators, and is async only because of the fact
that it calls Thunk::force().
I originally believed that this commit would make evaluation faster.
In fact it is slightly slower. I believe this is due to the added
vec![] allocation. I am investigating.
Prev-Nixpkgs-Benchmark: {"attrpath":"pkgsCross.aarch64-multiplatform.hello.outPath","peak-kbytes":"460048","system-seconds":"0.68","user-seconds":"5.73"}
This-Nixpkgs-Benchmark: {"attrpath":"pkgsCross.aarch64-multiplatform.hello.outPath","peak-kbytes":"460224","system-seconds":"0.67","user-seconds":"5.84"}
Change-Id: Ic627bc220d9c5aa3c5e68b9b8bf199837cd55af5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10212
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: Adam Joseph <adam@westernsemico.com>
This is part of a fix for b/338.
We should never use PartialOrd::partial_cmp().
All Nix types except floats are obviously totally-ordered. In
addition, it turns out that because Nix treats division by zero
rather than producing a NaN, and because it does not support
"negative zero", even floats are in fact totally ordered in Nix.
Therefore, every call to PartialOrd::partial_cmp() in tvix is an
error. We have to *implement* this function, but we should never
call it on built-in types.
Moreover, nix_cmp_ordering() currently returns an Option<Ordering>.
I'm not sure what was going on there, since it's impossible for it
to return None. This commit fixes it to return simply Ordering
rather than Option<Ordering>.
Change-Id: If5c084164cf19cfb38c5a15554c0422faa5f895d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10218
Autosubmit: Adam Joseph <adam@westernsemico.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This commit rewrites Value::nix_eq() into an equivalent. Except for
calls to Thunk::force(), the new form no longer uses generators, and
is async only because of the fact that it calls Thunk::force().
I believed that the nonrecursive form would be faster. It is, in
fact, slightly slower. I believe this is due to the vec![]
allocation; I am investigating.
Prev-Nixpkgs-Benchmark: {"attrpath":"pkgsCross.aarch64-multiplatform.hello.outPath","peak-kbytes":"459068","system-seconds":"0.71","user-seconds":"5.39"}
This-Nixpkgs-Benchmark: {"attrpath":"pkgsCross.aarch64-multiplatform.hello.outPath","peak-kbytes":"460048","system-seconds":"0.68","user-seconds":"5.73"}
Change-Id: I10f4868891e4b7475df13f0cbc41ec78dd985dd8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10118
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: Adam Joseph <adam@westernsemico.com>
This commit rewrites Thunk::force() so that it is not (directly)
self-recursive. It maintains a Vec of all the
previously-encountered thunks which point to the one it is currently
forcing, rather than recursively calling itself.
Benefits:
- Short term:
This commit saves the cost of a round-trip through the generator
machinery for the generators::request_force() which is removed by
this commit.
- Medium term:
Once a similar transformation has been applied to nix_cmp(),
nix_add(), nix_eq(), and coerce_to_string(), those four functions,
along with Thunk::force(), will make non-tail calls only to each
other. They can then be merged into a single tail-recursive
function which does not use the generator machinery at all:
enum Task { Cmp, Add, Eq, CoerceToString, Force};
fn Value::walk(task:Task, v1:Value, v2:Value) {
// ...
- Long term:
The long-term goal here is to use generators **only for builtins**
and [Marionette]-style remote control of the VM. In other words:
use `async` for things that actually involve concurrency. Calls
from the VM to builtins can then be blocking calls, because even
cppnix will overflow the stack if you make a MAX_STACK_DEPTH-deep
recursive call which passes through a builtin at every stack frame
(e.g. `{ func = builtins.sort (a: b: ... func ...) ...}`).
This way the inner "tight loop" of the interpreter doesn't pay the
costs of `async` and generators. These costs manifest in terms
of: performance, complex nonlocal control flow, and language
impediments (async Rust is a restricted subset of real Rust, and
is missing things like traits).
[Marionette]: https://firefox-source-docs.mozilla.org/testing/marionette/Intro.html
Change-Id: I6179b8abb2ea0492180fcb347f37595a14665777
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10039
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
If builtins.substring is invoked with (byte!!) offsets that aren't at
codepoint boundaries, return an error rather than panicking. This is
still incorrect (see b/337) but pushes the incorrectness forward a step.
Change-Id: I5a4261f2ff250874cd36489ef598dcf886669d04
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10199
Tested-by: BuildkiteCI
Autosubmit: grfn <grfn@gws.fyi>
Reviewed-by: sterni <sternenseemann@systemli.org>
This fixes a future clippy lint.
Change-Id: Ic830e94ef23595580c1037f10878c76bbb546dd9
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10110
Tested-by: BuildkiteCI
Reviewed-by: Adam Joseph <adam@westernsemico.com>
This commit adds Thunk::unwrap_or_clone(), which uses
Rc::try_unwrap() to avoid cloning the Value out of a an Rc which has
only one strong reference.
Change-Id: Icacefe0c823dcddf046d90c0c5cd5ed59fe976d4
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10037
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
Uses the standard library IntoIterator trait for the construction of
our iterators. Clippy complains about duplicating this.
While doing this, I opted to rename the `IntoIter` type into something
that is more useful to users, in case somebody ends up working with
these manually.
This fixes a clippy lint, and is related to b/321.
Change-Id: I851fde0d7b8b38d182343a0fd6d9f8dd2a33ee11
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9963
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
Autosubmit: tazjin <tazjin@tvl.su>
Delays allocation (through cloning) of the values to be compared
until *after* the keys have been compared.
Change-Id: I7d68c27d7a0fbcdcc387db7c092bce50ca4b94ea
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9900
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Similar to `into_iter_sorted`, add a marker function for call sites
that want *borrowed* sorted iteration.
Change-Id: I7c6f14e1ac43fdb14b861b3da183eb5d12bba139
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9899
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
builtins.intersectAttrs is used a _lot_ in nixpkgs eval, for whatever
reason. We previously had a very inefficient implementation that would
allocate for each comparison. It stuck out like a sore thumb in perf
analysis.
This moves to a custom algorithm with two iterators, one for the left
and one for the right side, advancing them along the (borrowed) map
keys until a match is found and allocation is required.
I've not made any effort to reduce the verbosity of this code, I don't
think it's worth it.
On my machine this reduces the mean runtime of evaluating
`nixpkgs.emacs.outPath` by ~8%.
Change-Id: Ie506d82cb8d5f45909628f771a6b73e0eca16b27
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9898
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
This commit adds a test case for b/281.
Change-Id: I8dfbfc0ff636184d7882530d8aefb329a3af9e5c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9288
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: Adam Joseph <adam@westernsemico.com>
Reviewed-by: flokli <flokli@flokli.de>
This commit makes catchable errors a variant of Value.
The main downside of this approach is that we lose the ability to
use Rust's `?` syntax for propagating catchable errors.
Change-Id: Ibe89438d8a70dcec29e016df692b5bf88a5cad13
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9289
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
This commit creates a separate enum for "catchable" errors (the kind
that `builtins.tryEval` can detect).
Change-Id: Ie81d1112526d852255d9842f67045f88eab192af
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9287
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: Adam Joseph <adam@westernsemico.com>
There's some more left, but they've been renamed/refactored out of
sight.
Change-Id: I41579dedc74342b4c5f8cb39d2995b5b0c90b0f4
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9372
Tested-by: BuildkiteCI
Reviewed-by: Connor Brewster <cbrewster@hey.com>
Autosubmit: flokli <flokli@flokli.de>
In cppnix 2.17, commit b72bc4a972fe568744d98b89d63adcd504cb586c, the
libexpr pretty-printing routine was fixed so that it would no longer
pretty-print attrsets with keywords in their attrnames incorrectly.
This commit implements the corresponding fix for tvix, fixes our
tests to work with cppnix>=2.17 oracles, and expands our test cases
to cover all the keywords.
Change-Id: I4b51389cd3a9c44babc8ab2a84b383b7b0b116ca
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9283
Autosubmit: Adam Joseph <adam@westernsemico.com>
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
replaceStrings would previously fail to replace the last character
in a string.
Change-Id: I43a7c960945350b2e7a5b731b7fdb617723eb38f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9151
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
This passes a unit value to the function.
Change-Id: I4df3ad8fb0f35c0f110cee3349971ae28ce2878c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9101
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
builtins.div ought to truncate towards zero so that
-(builtins.div a b) == builtins.div (-a) b
-(builtins.div a b) == builtins.div a (-b)
Change-Id: I8b7c08cd7f4fa8a1363c786d42c8d484f6cd133d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9006
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Some paths might use names that are not valid UTF-8. We should be able
to represent them.
We don't actually need to touch the PathInfo structures, as they need to
represent StorePaths, which come with their own harder restrictions,
which can't encode non-UTF8 data.
While this doesn't change any of the wire format of the gRPC messages,
it does however change the interface of tvix_eval::EvalIO - its
read_dir() method does now return a list of Vec<u8>, rather than
SmolStr. Maybe this should be OsString instead?
Change-Id: I821016d9a58ec441ee081b0b9f01c9240723af0b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8974
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
This explicitly documents behavior of C++ Nix that goes against the
intuition you'd gather from this document: that e.g. a simple select
from an attribute set causes a value to no longer be pointer equal to
its former self.
The point of documenting this is that we can show in a to be written
section on the use of pointer equality in nixpkgs that pointer equality
is only needed in a limited sense for evaluating it (C++ Nix's exterior
pointer equality). Tvix's pointer equality is far more powerful since
value identity preserving operations also preserve pointer equality,
generally speaking (this is because we implement interior pointer
equality in my made up terminology). This should eventually also be
documented.
Change-Id: I6ce7ef2d67b012f5ebc92f9e81bba33fb9dce7d0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8856
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
This fixes a subtle issue which would occasionally lead to a crash (e.g.
when evaluating (pkgs.systemd.outPath with --trace-runtime): With each
character in the string that has a multi byte representation in UTF-8,
the actual byte position and what tvix thought it was would get out of
sync. This could either lead to
* Tvix swallowing characters or jumbling characters if multi byte
characters would cause the tracked index to become out of sync with
the byte position before the first character to be escaped, or
* Tvix crashing if (in the same situation) the out of sync index would
be within a UTF-8 byte sequence.
Luckily, std's `char_indices()` iterator implements exactly what
`nix_escape_char()`'s original author had in mind with
`.chars().enumerate()`. Using `i + 1` for continuing is safe, since all
characters that need (in fact, can) to be escaped in Nix are represented
as a single byte in UTF-8.
Change-Id: I1c836f70cde3d72db1c644e9112852f0d824715e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8952
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>
The change allows applications that use tvix_serde for parsing
nix-based configuration to extend the language with domain-specific
set of features.
Change-Id: Ia86612308a167c456ecf03e93fe0fbae55b876a6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8848
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
I've noticed this behavior when writing the admittedly cursed test case
included in this CL. Alternatively we could use some sort of machinery
using `builtins.trace`, but I don't think we capture stderr anywhere.
I've elected to put this into the eval cache itself while C++ Nix does
it in builtins.import already, namely via `realisePath`. We don't have
an equivalent for this yet, since we don't support any kind of IfD, but
we could revise that later. In any case, it seems good to encapsulate
`ImportCache` in this way, as it'll also allow using file hashes as
identifiers, for example.
C++ Nix also does our equivalent of canon_path in `builtins.import`
which we still don't, but I suspect it hardly makes a difference.
Change-Id: I05004737ca2458a4c67359d9e7d9a2f2154a0a0f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8839
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
When dealing with a formal argument in a function argument pattern that
has a default expression, there are two different things that can happen
at runtime: Either we select its value from the passed attribute
successfully or we need to use the default expression. Both of these may
be thunks and both of these may need finalisers. However, in the former
case this is taken care of elsewhere, the value will always be finalised
already if necessary. In the latter case we may need to finalise the
thunk resulting from the default expression. However, the thunk
corresponding to the expression may never end up in the local's stack
slot. Since finalisation goes by stack slot (and not constants), we need
to prevent a case where we don't fall back to the default expression,
but finalise anyways.
Previously, we worked around this by making `OpFinalise` ignore
non-thunks. Since finalisation of already evaluated thunks still
crashed, the faulty compilation of function pattern arguments could
still cause a crash.
As a new approach, we reinstate the old behavior of `OpFinalise` to
crash whenever encountering something that is either not a thunk or
doesn't need finalisation. This can also help catching (similar)
miscompilations in the future. To then prevent the crash, we need to
track whether we have fallen back or not at runtime. This is done using
an additional phantom on the stack that holds a new `FinaliseRequest`
value. When it comes to finalisation we check this value and
conditionally execute `OpFinalise` based on its value.
Resolves b/261 and b/265 (partially).
Change-Id: Ic04fb80ec671a2ba11fa645090769c335fb7f58b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8705
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>
Adds new tests for foldl', intersectAttrs as well as fills in missing
.exp files.
New test cases we don't pass:
- fromTOML timestamp capabilities
- path antiquotation
- replaceStrings is lazier on C++ Nix master
The C++ Nix revision used is 7066d21a0ddb421967980094222c4bc1f5a0f45a.
Change-Id: Ic619c96e2d41e6c5ea6fa93f9402b12e564af3c5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8778
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
genericClosure has very limited support for pointer equality: It relies
on comparison (not equality!) in C++ Nix, so as soon as C++ Nix supports
comparing lists (langVersion >= 6) we can rely on pointer equality for
key.
Since Tvix uses equality, not comparison for the insert, our behavior is
currently different, as documented by the notyetpassing tests.
Change-Id: Ifcd741ed4fc3ccc3825f7038875d56a9918b786a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8720
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
