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2023-12-12 r/7201 fix(tvix/eval): builtins.filter: propagate catchablesAdam Joseph1-2/+5
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 r/7200 feat(tvix/eval): builtins.hashString: add placeholderAdam Joseph1-0/+12
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 r/7199 fix(tvix/eval): builtins.getAttr: propagate catchablesAdam Joseph1-0/+6
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 r/7198 fix(tvix/eval): builtins.elemAt: propagate catchablesAdam Joseph1-0/+6
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 r/7196 fix(tvix/eval): propagate catchables through builtins.splitVersionAdam Joseph1-0/+3
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 r/7195 feat(tvix/eval): builtins.hasContext: placeholder implementationAdam Joseph1-0/+8
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 r/7194 fix(tvix/eval): baseNameOf should not coerce paths into stringsAdam Joseph1-4/+12
... 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 r/7193 fix(tvix/eval): add unimplemented __curPos and builtins.filterSourceAdam Joseph1-0/+17
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 r/7176 feat(tvix/eval): nonrecursive coerce_to_string()Adam Joseph1-6/+21
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 r/7175 feat(tvix/eval): nonrecursive deep_force()Adam Joseph1-3/+3
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 r/7169 fix(tvix/eval): preserve catchables in nix_cmp_ordering(), fix b/338Adam Joseph1-4/+5
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 r/7167 feat(tvix/eval): nonrecursive nix_cmp_ordering(), fixes b/339Adam Joseph1-1/+2
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 r/7166 fix(tvix/eval): never use partial_cmp() (partial fix b/338)Adam Joseph1-1/+1
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
2023-12-05 r/7119 fix(tvix/eval): Return error rather than panicking on bad substringAspen Smith1-1/+1
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>
2023-11-25 r/7065 refactor(tvix/eval): use `or_default` helper in entry APIVincent Ambo1-3/+1
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>
2023-11-05 r/6955 chore(tvix): fix trivial clippy lintsVincent Ambo1-2/+2
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>
2023-11-03 r/6930 refactor(tvix/eval): more efficiently intersect attributesVincent Ambo1-9/+70
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>
2023-09-24 r/6650 fix(tvix/eval): fix b/281 by adding Value::CatchableAdam Joseph3-43/+75
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 r/6649 refactor(tvix/eval): factor CatchableErrorKind out of ErrorKindAdam Joseph1-2/+4
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>
2023-08-24 r/6523 fix(tvix/eval): off-by-one in replaceStringsLinus Heckemann1-1/+1
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>
2023-08-20 r/6503 refactor(tvix/eval): cargo clippy (len() is usize)Florian Klink1-1/+1
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
2023-07-22 r/6439 feat(tvix/store/proto): use Bytes instead of Vec<u8>Florian Klink1-2/+4
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>
2023-07-21 r/6436 refactor(tvix/store): use bytes for node names and symlink targetsFlorian Klink1-1/+2
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
2023-06-22 r/6344 feat(tvix/eval): allow extending builtins outside of tvix_evalEvgeny Zemtsov2-0/+2
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
2023-06-20 r/6336 fix(tvix/eval): only finalise formal arguments if defaultingsterni1-1/+2
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>
2023-06-12 r/6267 fix(tvix/eval): allow negative substring lengthsLinus Heckemann1-6/+5
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]: https://github.com/NixOS/nix/blob/ecae62020b64914d9859a71ce197d03688c6133c/src/libexpr/primops.cc#L3597 [2]: https://github.com/NixOS/nixpkgs/blob/c7c298471676ac1c7789ab3c424fbcebecaa6791/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
2023-05-26 r/6207 fix(tvix): don't call function eagerly in genList, map & mapAttrssterni1-5/+25
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>
2023-05-12 r/6135 fix(tvix/eval): builtins.trace prints to stderrVincent Ambo1-1/+1
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>
2023-03-17 r/6022 fix(tvix/eval): use coerce_to_string in builtins.substringVincent Ambo1-1/+1
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 r/6020 chore(tvix/eval): remove some dead codeVincent Ambo1-31/+0
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
2023-03-13 r/5983 fix(tvix/eval): emit warnings from builtins.import againVincent Ambo1-3/+4
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 r/5979 fix(tvix/eval): implement cppnix JSON-serialisation semanticsVincent Ambo2-31/+4
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 r/5977 fix(tvix/eval): handle toJSON on attribute sets with `outPath`Vincent Ambo1-6/+23
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 r/5976 fix(tvix/eval): handle `__toString` when JSON-serialising attrsetsVincent Ambo1-0/+9
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 r/5969 refactor(tvix/eval): box PathBufVincent Ambo1-3/+3
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 r/5968 chore(tvix/eval): remove `From<SmolStr> for NixString` instanceVincent Ambo1-5/+4
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 r/5966 refactor(tvix/eval): wrap NixList in RcVincent Ambo1-3/+3
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 r/5964 refactor(tvix/eval): flatten call stack of VM using generatorsVincent Ambo2-312/+328
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
2023-03-04 r/5888 refactor(tvix/eval): remove VM argument from suspended native thunksVincent Ambo1-7/+1
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 r/5887 refactor(tvix/eval): insert storeDir "builtin" in eval startupVincent Ambo1-10/+0
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
2023-03-03 r/5870 chore(tvix/eval): fix clippy warningsVincent Ambo1-2/+2
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>
2023-02-13 r/5850 chore(tvix/eval): use writeln for newline stringAaqa Ishtyaq1-2/+2
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>
2023-02-03 r/5828 fix(tvix/eval): ensure all evaluated thunks are correctly memoizedVincent Ambo1-2/+1
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>
2023-02-02 r/5823 fix(tvix/eval): unsafeDiscardStringContext is a no-opVincent Ambo1-4/+2
... 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
2023-01-31 r/5795 fix(tvix/eval): allow builtins.toXML to serialise any functionVincent Ambo1-1/+13
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>
2023-01-25 r/5754 feat(tvix/eval): implement builtins.fromTOMLFlorian Klink1-0/+7
This allows parsing TOML from Tvix. We can enable the eval-okay-fromTOML testcase from nix_tests. It uses the `toml` crate, and the serde integration it brings with it. Change-Id: Ic6f95aacf2aeb890116629b409752deac49dd655 Reviewed-on: https://cl.tvl.fyi/c/depot/+/7920 Autosubmit: flokli <flokli@flokli.de> Reviewed-by: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI
2023-01-20 r/5707 refactor(tvix/eval): directly return builtin tuples from macroVincent Ambo2-16/+3
All invocations of the builtin macro had to previously filter through the `builtin_tuple` function, but it's more sensible to directly return these from the macro. Change-Id: I45600ba84d56c9528d3e92570461c319eea595ce Reviewed-on: https://cl.tvl.fyi/c/depot/+/7825 Tested-by: BuildkiteCI Reviewed-by: flokli <flokli@flokli.de>
2023-01-17 r/5675 refactor(tvix/eval): remove `Box` in new_suspended_nativeVincent Ambo1-2/+2
This is unnecessary, Rc already provides all the boxing we need. Change-Id: I08cf0939c48da43f04c847526c7e5dae5336d528 Reviewed-on: https://cl.tvl.fyi/c/depot/+/7749 Tested-by: BuildkiteCI Reviewed-by: grfn <grfn@gws.fyi> Reviewed-by: sterni <sternenseemann@systemli.org>
2023-01-16 r/5664 feat(tvix/eval): implement builtins.toXMLVincent Ambo2-0/+135
Change-Id: I009efc53a8e98f0650ae660c4decd8216e8a06e7 Reviewed-on: https://cl.tvl.fyi/c/depot/+/7835 Reviewed-by: flokli <flokli@flokli.de> Tested-by: BuildkiteCI
2023-01-12 r/5654 fix(tvix/eval): len_without_is_empty clippy warnAaqa Ishtyaq1-1/+1
This CL addresses clippy warning len_without_is_empty which expects `.is_empty()` method to be present when implementing `.len()` method for an item. Change-Id: I8878db630b9ef5853649a906b764a33299bb5dc8 Signed-off-by: Aaqa Ishtyaq <aaqaishtyaq@gmail.com> Reviewed-on: https://cl.tvl.fyi/c/depot/+/7806 Reviewed-by: flokli <flokli@flokli.de> Tested-by: BuildkiteCI