Commit graph

205 commits

Author SHA1 Message Date
Adam Joseph
2af8174e2e fix(tvix/eval): builtins.match: propagate catchables
Change-Id: I14c9e625c91369e10d0c00380dca992811ae9059
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10346
Reviewed-by: sterni <sternenseemann@systemli.org>
Autosubmit: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
2023-12-29 21:34:45 +00:00
sterni
7165ebc43b fix(tvix/eval): remove incorrect imports when coercing
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>
2023-12-14 13:15:23 +00:00
Adam Joseph
243a4b5699 fix(tvix/eval): substring: propagate catchables
Change-Id: Ia9b7858c817fbc9c95a3d1c2855b2445f7830e8d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10326
Tested-by: BuildkiteCI
Autosubmit: Adam Joseph <adam@westernsemico.com>
Reviewed-by: tazjin <tazjin@tvl.su>
2023-12-12 17:51:29 +00:00
Adam Joseph
c5f58d4af3 fix(tvix/eval): baseNameOf: propagate catchables
Change-Id: Id8dc772ea8f338dfd243210f4108f79072570c3b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10324
Autosubmit: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
2023-12-12 17:50:56 +00:00
Adam Joseph
2565a21aa9 fix(tvix/eval): builtins.length: propagate catchables
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
2023-12-12 17:49:54 +00:00
Adam Joseph
1ddfed9825 fix(tvix/eval): builtins.filter: propagate catchables
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>
2023-12-12 17:35:39 +00:00
Adam Joseph
25dd1458b9 feat(tvix/eval): builtins.hashString: add placeholder
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>
2023-12-12 17:35:06 +00:00
Adam Joseph
8c8409c0d2 fix(tvix/eval): builtins.getAttr: propagate catchables
Change-Id: I84b6b8f8568d57614a03aff0d6069e0bc27357bf
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10310
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Autosubmit: Adam Joseph <adam@westernsemico.com>
2023-12-12 17:34:34 +00:00
Adam Joseph
afba150036 fix(tvix/eval): builtins.elemAt: propagate catchables
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>
2023-12-12 17:34:02 +00:00
Adam Joseph
29464fc65b fix(tvix/eval): propagate catchables through builtins.splitVersion
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>
2023-12-12 17:21:53 +00:00
Adam Joseph
012b44244b feat(tvix/eval): builtins.hasContext: placeholder implementation
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>
2023-12-12 17:21:53 +00:00
Adam Joseph
531f0c0c42 fix(tvix/eval): baseNameOf should not coerce paths into strings
... 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>
2023-12-12 17:21:21 +00:00
Adam Joseph
8d4aa2c15c fix(tvix/eval): add unimplemented __curPos and builtins.filterSource
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>
2023-12-12 17:20:50 +00:00
Adam Joseph
1ac57b0d1c feat(tvix/eval): nonrecursive coerce_to_string()
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>
2023-12-12 14:54:46 +00:00
Adam Joseph
3701379745 feat(tvix/eval): nonrecursive deep_force()
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>
2023-12-12 14:36:02 +00:00
Adam Joseph
ad566999ca fix(tvix/eval): preserve catchables in nix_cmp_ordering(), fix b/338
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>
2023-12-12 14:26:46 +00:00
Adam Joseph
edbd5055a1 feat(tvix/eval): nonrecursive nix_cmp_ordering(), fixes b/339
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>
2023-12-12 14:26:46 +00:00
Adam Joseph
8a40f75c2d fix(tvix/eval): never use partial_cmp() (partial fix b/338)
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
2023-12-12 14:26:46 +00:00
Aspen Smith
8135a8d38c fix(tvix/eval): Return error rather than panicking on bad substring
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>
2023-12-05 23:12:23 +00:00
Vincent Ambo
e65fa82d74 refactor(tvix/eval): use or_default helper in entry API
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>
2023-11-25 15:48:46 +00:00
Vincent Ambo
b3b1f649d6 chore(tvix): fix trivial clippy lints
Relates to b/321.

Change-Id: I37284f89b186e469eb432e2bbedb37aa125a6ad4
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9961
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
Autosubmit: tazjin <tazjin@tvl.su>
2023-11-05 20:28:37 +00:00
Vincent Ambo
d91fcd4f28 refactor(tvix/eval): more efficiently intersect attributes
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>
2023-11-03 09:24:30 +00:00
Adam Joseph
05f42519b5 fix(tvix/eval): fix b/281 by adding Value::Catchable
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
2023-09-24 21:54:10 +00:00
Adam Joseph
926459ce69 refactor(tvix/eval): factor CatchableErrorKind out of ErrorKind
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>
2023-09-24 21:54:09 +00:00
Linus Heckemann
a3dbb60213 fix(tvix/eval): off-by-one in replaceStrings
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>
2023-08-24 10:07:48 +00:00
Florian Klink
def773d4d5 refactor(tvix/eval): cargo clippy (len() is usize)
Change-Id: I9d931ffcc03c6df7c0392dbc1c9a4ae0e3804213
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9099
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
2023-08-20 21:51:04 +00:00
Florian Klink
432222f098 feat(tvix/store/proto): use Bytes instead of Vec<u8>
Makes use of https://github.com/tokio-rs/prost/pull/341, which makes our
bytes field cheaper to clone.

It's a bit annoying to configure due to
https://github.com/hyperium/tonic/issues/908, but the workaround does
get the job done.

Change-Id: I25714600b041bb5432d3adf5859b151e72b12778
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8975
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: flokli <flokli@flokli.de>
2023-07-22 09:03:02 +00:00
Florian Klink
72e82ffcb1 refactor(tvix/store): use bytes for node names and symlink targets
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
2023-07-21 19:01:49 +00:00
Evgeny Zemtsov
c8fcdca4eb feat(tvix/eval): allow extending builtins outside of tvix_eval
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
2023-06-22 20:19:06 +00:00
sterni
4516cd09c5 fix(tvix/eval): only finalise formal arguments if defaulting
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>
2023-06-20 10:07:44 +00:00
Linus Heckemann
5733274876 fix(tvix/eval): allow negative substring lengths
Nix uses string::substr without checking the sign of the length[1].
The NixOS testing infrastructure relies on this[2], and on the
implicit conversion of that to the maximum possible value for a
size_t.

[1]: ecae62020b/src/libexpr/primops.cc (L3597)
[2]: c7c2984716/nixos/lib/testing/driver.nix (L29)

Change-Id: I6d0caf6830b6bda3fdf44c40c81de6a1befeca7b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8746
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
2023-06-12 08:38:49 +00:00
sterni
3b33c19a9c fix(tvix): don't call function eagerly in genList, map & mapAttrs
mapAttrs, map and genList call Nix functions provided by the caller and
store the result of applying them in a Nix data structure that does not
force all of its contents when forced itself. This means that when such
a builtin application is forced, the Nix function calls performed by the
builtin should not be forced: They may be forced later, but it is also
possible that they will never be forced, e.g. in

    builtins.length (builtins.map (builtins.add 2) [ 1 2 3 ])

it is not necessary to compute a single application of builtins.add.

Since request_call_with immediately performs the function call
requested, Tvix would compute function applications unnecessarily before
this change. Because this was not followed by a request_force, the
impact of this was relatively low in Nix code (most functions return a
new thunk after being applied), but it was enough to cause a lot of
bogus builtins.trace applications when evaluating anything from
`lib.modules`. The newly added test includes many cases where Tvix
previously incorrectly applied a builtin, breaking a working expression.

To fix this we add a new helper to construct a Thunk performing a
function application at runtime from a function and argument given as
`Value`s. This mimics the compiler's compile_apply(), but does itself
not require a compiler, since the necessary Lambda can be constructed
independently.

I also looked into other builtins that call a Nix function to verify
that they don't exhibit such a problem:

- Many builtins immediately use the resulting value in a way that makes
  it necessary to compute all the function calls they do as soon as
  the outer builtin application is forced:

  * all
  * any
  * filter
  * groupBy
  * partition

- concatMap needs to (shallowly) force the returned list for
  concatenation.

- foldl' is strict in the application of `op` (I added a comment that
  makes this explicit).

- genericClosure needs to (shallowly) force the resulting list and some
  keys of the attribute sets inside.

Resolves b/272.

Change-Id: I1fa53f744bcffc035da84c1f97ed25d146830446
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8651
Autosubmit: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
2023-05-26 22:35:39 +00:00
Vincent Ambo
969fbcd6d4 fix(tvix/eval): builtins.trace prints to stderr
Change-Id: Icf577396035474d6977e627058aba5805c61985e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8563
Tested-by: BuildkiteCI
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: flokli <flokli@flokli.de>
2023-05-12 12:50:59 +00:00
Vincent Ambo
b78ae941a4 fix(tvix/eval): use coerce_to_string in builtins.substring
This actually uses coercion under the hood in C++ Nix. See the test
for an example.

Change-Id: Id56b364acf269225b6829d0b600e0222f8b3608d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8322
Reviewed-by: andi <andi@notmuch.email>
Tested-by: BuildkiteCI
2023-03-17 19:17:29 +00:00
Vincent Ambo
b5f5a1595d chore(tvix/eval): remove some dead code
This was commented out and forgotten during the generator refactor, oh
well.

Change-Id: I474b685159a955a846db462da0dd0067af177b04
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8321
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
2023-03-17 11:01:07 +00:00
Vincent Ambo
5d9bfd7735 fix(tvix/eval): emit warnings from builtins.import again
Wires up generator logic to emit warnings that already have spans
attached again.

Change-Id: I9f878cec3b9d4f6f7819e7c71bab7ae70bd3f08b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8224
Tested-by: BuildkiteCI
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
2023-03-13 20:30:59 +00:00
Vincent Ambo
939cebd0f1 fix(tvix/eval): implement cppnix JSON-serialisation semantics
This drops the usage of serde::Serialize, as the trait can not be used
to implement the correct semantics (function colouring!).

Instead, a manual JSON serialisation function is written which
correctly handles toString, outPath and other similar weirdnesses.

Unexpectedly, the eval-okay-tojson test from the C++ Nix test suite
now passes, too.

This fixes an issue where serialising data structures containing
derivations to JSON would fail.

Change-Id: I5c39e3d8356ee93a07eda481410f88610f6dd9f8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8209
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
2023-03-13 20:30:59 +00:00
Vincent Ambo
dfd0066de5 fix(tvix/eval): handle toJSON on attribute sets with outPath
These are serialised as the serialisation of the value of that field.

Change-Id: Ida51708b1f43ce09b0ec835f4e265918aa31dd09
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8205
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
2023-03-13 20:30:59 +00:00
Vincent Ambo
7d339d2762 fix(tvix/eval): handle __toString when JSON-serialising attrsets
These must be serialised to a JSON string of the *result* of coercing
the function application to a string.

Change-Id: Ib7f49ccd950503ddbdbf99643cd59565e26b50da
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8204
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
2023-03-13 20:30:59 +00:00
Vincent Ambo
43d04d9b98 refactor(tvix/eval): box PathBuf
This shaves another 8 bytes off Value. How did that type get so big?!

Change-Id: I65e9b59a1636bd57e3cc4aec5fea16887070b832
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8153
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
2023-03-13 20:30:59 +00:00
Vincent Ambo
52b7a76268 chore(tvix/eval): remove From<SmolStr> for NixString instance
No longer needed, and in some cases caused some extra work.

Change-Id: I64e8e7292573bdc92a9c7a8e470e33f8c526f311
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8152
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
2023-03-13 20:30:59 +00:00
Vincent Ambo
4bbfeaf1cb refactor(tvix/eval): wrap NixList in Rc
The size of a `Vector<Value>` is 64 *bytes*, which is quite large, and
it bloated the entire Value type to this size.

This change adds an indirection for the inner vector through Rc.
Initially I tried to use a Box, but this breaks pointer equality
guarantees for the Vector when it is small enough to be inlined.

This reduces the size of Value from 64 to 32 bytes.

Change-Id: Ic3211e861b1966c78b2c3d536ba291fea92647fd
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8150
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
2023-03-13 20:30:59 +00:00
Vincent Ambo
025c67bf4d refactor(tvix/eval): flatten call stack of VM using generators
Warning: This is probably the biggest refactor in tvix-eval history,
so far.

This replaces all instances of trampolines and recursion during
evaluation of the VM loop with generators. A generator is an
asynchronous function that can be suspended to yield a message (in our
case, vm::generators::GeneratorRequest) and receive a
response (vm::generators::GeneratorResponsee).

The `genawaiter` crate provides an interpreter for generators that can
drive their execution and lets us move control flow between the VM and
suspended generators.

To do this, massive changes have occured basically everywhere in the
code. On a high-level:

1. The VM is now organised around a frame stack. A frame is either a
   call frame (execution of Tvix bytecode) or a generator frame (a
   running or suspended generator).

   The VM has an outer loop that pops a frame off the frame stack, and
   then enters an inner loop either driving the execution of the
   bytecode or the execution of a generator.

   Both types of frames have several branches that can result in the
   frame re-enqueuing itself, and enqueuing some other work (in the
   form of a different frame) on top of itself. The VM will eventually
   resume the frame when everything "above" it has been suspended.

   In this way, the VM's new frame stack takes over much of the work
   that was previously achieved by recursion.

2. All methods previously taking a VM have been refactored into async
   functions that instead emit/receive generator messages for
   communication with the VM.

   Notably, this includes *all* builtins.

This has had some other effects:

- Some test have been removed or commented out, either because they
  tested code that was mostly already dead (nix_eq) or because they
  now require generator scaffolding which we do not have in place for
  tests (yet).

- Because generator functions are technically async (though no async
  IO is involved), we lose the ability to use much of the Rust
  standard library e.g. in builtins. This has led to many algorithms
  being unrolled into iterative versions instead of iterator
  combinations, and things like sorting had to be implemented from scratch.

- Many call sites that previously saw a `Result<..., ErrorKind>`
  bubble up now only see the result value, as the error handling is
  encapsulated within the generator loop.

  This reduces number of places inside of builtin implementations
  where error context can be attached to calls that can fail.
  Currently what we gain in this tradeoff is significantly more
  detailed span information (which we still need to bubble up, this
  commit does not change the error display).

  We'll need to do some analysis later of how useful the errors turn
  out to be and potentially introduce some methods for attaching
  context to a generator frame again.

This change is very difficult to do in stages, as it is very much an
"all or nothing" change that affects huge parts of the codebase. I've
tried to isolate changes that can be isolated into the parent CLs of
this one, but this change is still quite difficult to wrap one's mind
and I'm available to discuss it and explain things to any reviewer.

Fixes: b/238, b/237, b/251 and potentially others.
Change-Id: I39244163ff5bbecd169fe7b274df19262b515699
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8104
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Reviewed-by: Adam Joseph <adam@westernsemico.com>
Tested-by: BuildkiteCI
2023-03-13 20:30:59 +00:00
Vincent Ambo
bfb787a6c5 refactor(tvix/eval): remove VM argument from suspended native thunks
Because they do not use it, and it can not be passed with the coming
generator refactoring.

Change-Id: I0d96f2357a7ee79cd8a0f401583d4286230d4a6b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8146
Tested-by: BuildkiteCI
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
2023-03-04 15:53:36 +00:00
Vincent Ambo
38fd3cb292 refactor(tvix/eval): insert storeDir "builtin" in eval startup
Instead of using a suspended native thunk, calculate and optionally
insert the storeDir builtin when the VM is constructed.

We already have the IO handle available at this point and can just
check whether a storeDir is present, and insert its absolute value as
a builtin.

Change-Id: If966eee6ff26dc888b6e888e7c46170c0c346b05
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8145
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
2023-03-04 15:53:36 +00:00
Vincent Ambo
344c119370 chore(tvix/eval): fix clippy warnings
Change-Id: I4c02f0104c455ac00a3f299c1fbf75cbb08e8972
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8142
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Autosubmit: tazjin <tazjin@tvl.su>
2023-03-03 11:01:52 +00:00
Aaqa Ishtyaq
fc61dff037 chore(tvix/eval): use writeln for newline string
This CL address clippy warning which expects to
use `writeln` instead of `write` for strings with
new line.

Change-Id: Ia72a07502c60cfd489ecf1e3833b9d42d44a8b17
Signed-off-by: Aaqa Ishtyaq <aaqaishtyaq@gmail.com>
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8030
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
2023-02-13 19:45:58 +00:00
Vincent Ambo
3419f63575 fix(tvix/eval): ensure all evaluated thunks are correctly memoized
This fixes a very complicated bug (b/246). Evaluation
progresses *much* further after this, leading to several less
complicated bugs likely being uncovered by this

What was the problem?
=====================

Previously, when evaluating a thunk, we had a code path that looked
like this:

    match *thunk {
        ThunkRepr::Evaluated(Value::Thunk(ref inner_thunk)) => {
            let inner_repr = inner_thunk.0.borrow().clone();
            drop(thunk);
            self.0.replace(inner_repr);
        }
        /* ... */
    }

This code path created a copy of the inner `ThunkRepr` of a nested
thunk, and moved that copy into the `ThunkRepr` of the parent.

The effect of this was that the original `ThunkRepr` (unforced!) lived
on in the original thunk, without the memoization of the subsequent
forcing applying to it.

This had the result that Tvix would repeatedly evaluate these thunks
without ever memoizing them, if they occured repeatedly as shared
inner thunks. Most notably, this would *always* occur when
builtins.import was used.

What's the solution?
====================

I have completely rewritten `Thunk::force_trampoline_self` to make all
flows that can occur in it explicit. I have also removed the outer
loop inside of that function, and resorted to more use of trampolining
instead.

The function is now well-commented and it should be possible to read
it from top-to-bottom and get a general sense of what is going on,
though the trampolining itself (which is implemented in the VM) needs
to be at least partially understood for this.

What's the new problem(s)?
==========================

One new (known) problem is that we have to construct `Error` instances
in all error types here, but we do not have spans available in some
thunk-related situations. Due to b/238 we cannot ask the VM for an
arbitrary span from the callsite leading to the force. This means that
there are now code paths where, under certain conditions, causing an
evaluation error during thunk forcing will panic.

To fix this we will need to investigate and fix b/238, and/or add a
span tracking mechanism to thunks themselves.

What other impacts does this have?
==================================

With this commit, eval of nixpkgs mostly succeeds (things like stdenv
evaluate to the same hashes for us and C++ Nix, meaning we now
construct identical derivations without eval breaking).

Due to this we progress much further into nixpkgs, which lets us
uncover more additional bugs. For example, after this commit we can
quickly see that cl/7949 introduces some kind of behavioural issue and
should not be merged as-is (this was not apparent before).

Additionally, tvix-eval is now seemingly very fast. When doing
performance analysis of a nixpkgs eval, we now mostly see the code
path for shelling out to C++ Nix to add things to the store in there.
We still need those code paths, so we can not (yet) do a performance
analysis beyond that.

Change-Id: I738525bad8bc5ede5d8c737f023b14b8f4160612
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8012
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
2023-02-03 10:47:18 +00:00
Vincent Ambo
503e6810e7 fix(tvix/eval): unsafeDiscardStringContext is a no-op
... not just a TODO.

Most use-cases of unsafeDiscardStringContext are for cases where a
string is processed in some ways and no longer contains a "physical"
reference, but still has its context attached in C++ Nix.

We don't need to do this. This does diverge in behaviour in use-cases
related to build scheduling, but that whole behaviour will be
different in Tvix.

Change-Id: I4056d4c09f62d44d6bd52b791db03fe5556672b5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8016
Reviewed-by: flokli <flokli@flokli.de>
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
2023-02-02 14:30:32 +00:00
Vincent Ambo
ddf6e6cf47 fix(tvix/eval): allow builtins.toXML to serialise any function
This adds a fake argument name to builtins.toXML which allows toXML to
serialise any value instead of panicking on functions. We do still
have to fix the value itself, eventually, though.

Change-Id: I2e330ecddcd80442b4fac5eced64431ac86123ba
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7962
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
2023-01-31 15:31:30 +00:00