I'm still trying to work out the exact stack invariants for tvix.
We really should add assertions for them; getting the stack messed
up is no fun. This commit adds one simple assertion. It also adds
a missing stack-push (my mistake) in one place, which was uncovered
by the assertion.
Change-Id: I9d8b4bd1702d954e325832c5935b0d7e3eb68422
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10369
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
r/7176 introduced an incorrect assumption was the benefit of the
nonrecursive coercion algorithm, namely that a coercion operation always
returns a non empty string. This allows to detect whether we are
coercing a list or not by checking if the intermediate result is empty
or not. Unfortunately, coercing null and false yields an empty string,
so we need to explicitly track whether we are coercing a list.
Updated the test case to hopefully catch similar bugs in the future. I'm
not a hundred percent certain I have not introduced a new edge case with
this, so it may be interesting to add a prop test case for this to
nix_oracle down the line. At least lists are the only nested data
structures that can be serialized as nested data structures, so the
problem is kind of limited.
Change-Id: Ia41e904356f1c41a9d35e4e65ec02f2fe5a4100e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10418
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Autosubmit: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
The default behavior of string coercion in C++ Nix is to weakly coerce
and import to store if necessary. There is a flag to make it strongly
coerce (coerceMore) and a flag that controls whether path values have
the corresponding file/directory imported into the store before
returning the (store) path as a string (copyToStore). We need to
implement our equivalent to the copyToStore (import_paths) flag for the
benefit of weak coercions that don't import into the store (dirOf,
baseNameOf, readFile, ...) and strong coercions that don't import into
the store (toString).
This makes coerce_to_string as well as CoercionKind weirder and more
versatile, but prevents us from reimplementing parts of the coercion
logic constantly as can be seen in the case of baseNameOf.
Note that it is not possible to test this properly in //tvix/eval tests
due to the lack of an appropriate EvalIO implementation being available.
Tests should be added to //tvix/glue down the line.
Change-Id: I8fb8ab99c7fe08e311d2ba1c36960746bf22f566
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10361
Autosubmit: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Reviewed-by: Adam Joseph <adam@westernsemico.com>
This matches the behavior of C++ Nix more closely where the decision is
made based on the first type based to ExprConcatStrings:
1f93fa2ed2/src/libexpr/eval.cc (L1967-L2025)
Note that this doesn't make a difference in any successful
evaluation (at least to my knowledge), but ensures that our error
messages will match C++ Nix more closely, e.g. in the case of
`1 + "string"`.
Change-Id: I8059930788f9c8d98baf98e3d93d8a060ef961f2
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10360
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: Adam Joseph <adam@westernsemico.com>
This commit fixes out builtins.length so it propagates catchables
like cppnix does.
Change-Id: I7670bec5eee1d4cd3f67a04c9a6808979fb56a8d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10315
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
This commit fixes builtins.filter so it propagates catchables
correctly.
Change-Id: Ib23a383bc5e272e42052205ffd1e94649a0ebc47
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10313
Autosubmit: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
This adds an unimplemented placeholder for builtins.hashString.
Change-Id: Ibc770103acf5dbc3ea7589ab5ca23fe6e07bd91a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10311
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: Adam Joseph <adam@westernsemico.com>
This commit fixes builtins.elemAt so it propagates catchables like
cppnix does.
Change-Id: Ieca5e128da17e78af0b14dae4a28a1ff8796e4f2
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10308
Autosubmit: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
This fixes our implementation of builtins.splitVersion so it
propagates catchables like cppnix does.
Change-Id: Id5d83ea76229f8c8f202aa42353cb609e67de43f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10305
Autosubmit: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Currently this just `throw`s a message explaining that it is not
implemented. This is necessary in order to allow enumerating the
nixpkgs release attrset (afaict only one package uses this builtin).
Change-Id: I45266d46af579ddb5856b192b6be4b481369543c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10302
Autosubmit: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
... since this may import them to the store which changes their
basename.
Fixes b/350.
Change-Id: Iabd08ff4d6a424c66d6d7784d7a96b0c078f0a91
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10298
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: Adam Joseph <adam@westernsemico.com>
This commit adds __curPos (to the global scope, yuck) and
builtins.filterSource. These are not implemented; forcing them will
produce the same result as `throw "message"`.
Unfortunately these two post-2.3 features are used throughout
nixpkgs. Since an unresolved indentifier is a catchable error, this
breaks the entire release eval. With this commit, it simply causes
those broken packages that use these features to appear as they are:
broken.
Change-Id: Ib43dea571f6a9fab4d54869349f80ee4ec5424c2
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10297
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: Adam Joseph <adam@westernsemico.com>
This commit fixes our handling of `throw` within an `assert`
condition.
Fixes: b/340
Change-Id: I40a383639ec266da50a853f16216b1b7868495da
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10318
Autosubmit: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
This commit fixes out `?` operator so it correctly propagates
catchables.
Change-Id: Iebaa153a8492101ee3ddd29893c98730ff331547
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10317
Autosubmit: Adam Joseph <adam@westernsemico.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Previously, using a catchable as either argument of OpAttrsSelect
would result in an unrecoverable error. This commit matches cppnix
behavior by propagating the catchable.
Change-Id: I4877f4068ec2b823225f185290693c101d0b9c9e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10303
Tested-by: BuildkiteCI
Autosubmit: Adam Joseph <adam@westernsemico.com>
Reviewed-by: tazjin <tazjin@tvl.su>
When attempting to call a Value, if it is a Value::Catchable we must
not cause an uncatchable failure. This commit simply reuses the
Value::Catchable as the result of attempting to call it. This is
safe because nix is designed so that nix code cannot distinguish
between different catchable failures -- they all look the same to
the interpreted code.
This fixes b/351.
Change-Id: Ibf763a08753e541843626182ff59fdbf15ea2959
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10300
Autosubmit: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
error[E006]: expected value of type 'bool', but found a 'internal[catchable]'
--> src/tests/tvix_tests/notyetpassing/eval-okay-test-catchables-in-implications.nix:1:43
|
1 | (builtins.tryEval (({ foo ? throw "up" }: foo -> true) { })).success
| ^^^^^^^^^^^
Relates to b/345
Change-Id: Ic331c32ea59bf67ae775f485b444dc6804ca13d5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10289
Tested-by: BuildkiteCI
Autosubmit: Adam Joseph <adam@westernsemico.com>
Reviewed-by: tazjin <tazjin@tvl.su>
This commit adds Opcode::OpJumpIfCatchable, which can be inserted
ahead of most VM operations which expect a boolean on the stack, in
order to handle catchables in branching position properly.
Other than remembering to patch the jump, no other changes should be
required.
This commit also fixes b/343 by emitting this new opcode when
compiling if-then-else. There are probably other places where we
need to do the same thing.
Change-Id: I48de3010014c0bbeba15d34fc0d4800e0bb5a1ef
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10288
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: Adam Joseph <adam@westernsemico.com>
This is a test case for b/343, wherein tvix dies if you try to
branch on an argument whose defaulted value is a catchable.
Change-Id: I891ca825e39ad14dda9f220f06d9591874fcd45d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10287
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
After this commit, the only non-builtins uses of generators are:
- coerce_to_string() uses generators::request_enter_lambda()
- Thunk::force() uses generators::request_enter_lambda()
That's it! Once those two are taken care of, GenCo can become an
implementation detail of `builtins::BuiltinGen`. No more crazy
nonlocal flow control within the interpreter: if you've got a GenCo
floating around in your code it's because you're writing a builtin,
which isn't part of the core interpreter. The interpreter won't
need GenCos to talk to itself anymore.
Technically generators::request_path_import() is also used by
coerce_to_string(), but that's just because the io_handle happens to
be part of the VM. There's no recursion-depth issue there, so the
call doesn't need to go through the generator mechanism
(request_path_import() doesn't call back to the interpreter!)
Change-Id: I83ce5774d49b88fdafdd61160975b4937a435bb0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10256
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: Adam Joseph <adam@westernsemico.com>
This commit implements deep_force() nonrecursively, by maintaining
an explicit stack rather than using the call stack for recursion.
As an added bonus, we don't need to pass around the SharedThunkSet
anymore, and can in fact completely eliminate SharedThunkSet.
Change-Id: I7c4f59f37834d451a28bf6be317eb0a90eac4ee6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10252
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: Adam Joseph <adam@westernsemico.com>
The comment explaining ThunkSet makes it seem like it does the same
think as ThunkRepr::Blackhole. In fact neither one is a substitute
for the other. Let's explain the difference.
Change-Id: I89ceaaa9d3c499edbc7d48f70ca5d11f97666c43
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10250
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: Adam Joseph <adam@westernsemico.com>
LightSpan::Delayed was introduced in commit
bf286a54bc which claimed that "This
reduces the eval time for `builtins.length (builtins.attrNames
(import <nixpkgs> {}))` by *one third*!"
I am unable to reproduce this result. In fact, dropping the
LightSpan::Delayed variant of the enum makes eval of the same
expression slightly faster! I also tried a large evaluation
(pkgsCross...hello) and got similar results: slightly faster,
slightly less memory. See git footers.
I suspect that there was some unrelated horrific inefficiency that
has since been fixed. The avoided computation in `get_span()` is
nothing more than a binary search! If this were in fact a major
performance issue we could simply precompute the mapping from
CodeIdx to Span when the Chunk becomes immutable (i.e. at the end of
the compilation process, when compiler backtracking is no longer a
concern). Since a Span is just 64 bits this is not a space issue,
and since binary search is much simpler than compiling Nix
expressions it isn't a performance issue either.
Technically there is no longer any reason to have LightSpan since it
is now a single-variant enum. However there is no rush to remove
it, since Rust will optimize its representation into the same thing
you'd get if you replaced LightSpan by Span.
Prev-Benchmark: {"nixpkgs-attrnames":{"kbytes":"233824","system":"0.32","user":"2.02"}}
This-Benchmark: {"nixpkgs-attrnames":{"kbytes":"230192","system":"0.29","user":"2.00"}}
Prev-Benchmark: {"pkgsCross.aarch64-multiplatform.hello.outPath":{"kbytes":"458936","system":"0.73","user":"5.36"}}
This-Benchmark: {"pkgsCross.aarch64-multiplatform.hello.outPath":{"kbytes":"451808","system":"0.53","user":"5.10"}}
Change-Id: Ib9e04806850aa1fc4e66e2a042703986440a7b4e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10254
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
This is just a alias for Result<_, io::Error>, but shorter.
Change-Id: I7c22f61b85e3014885a747b5c1e5abd11b0ef17d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10327
Tested-by: BuildkiteCI
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
This commit fixes b/338 by properly propagating catchables through
comparison operations.
Change-Id: I6b0283a40f228ecf9a6398d24c060bdacb1077cf
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10221
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: Adam Joseph <adam@westernsemico.com>
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
