This change is quite verbose, so a little bit of explaining:
1. To correctly format parse errors, errors must be able to return
more than one annotated span (the parser returns a list of errors
for each span).
To accomplish this, the structure of how the `Diagnostic` struct
which formats an error is constructed has changed to delegate the
creation of the `SpanLabel` vector to the kind of error.
2. The rnix structures don't have human-readable output formats by
default, so some verbose methods for formatting them in
human-readable ways have been added in the errors module. We might
want to move these out into a submodule.
3. In many cases, the errors returned by rnix are a bit strange - so
while we format them with all information that is easily available
they may look weird or not necessarily help users. Consider this CL
only a first step in the right direction.
Change-Id: Ie7dd74751af9e7ecb35d751f8b087aae5ae6e2e8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6871
Reviewed-by: sterni <sternenseemann@systemli.org>
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This enables the use of string paths (and, in the future,
derivations), as long as their string values represent an absolute
path.
Change-Id: I4b198efeb70415ed52f58bd1da6fa79a24dad14c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6866
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
This adds an initial working version of builtins.import which
encapsulates the entire functionality of `import` within the builtin
itself, without requiring any changes in the compiler or VM.
The key insight that enables this is that we can simply return a Thunk
from `import` that is constructed from the output of running the
compiler and - ta-da! - no other component needs to know about it.
A couple of notes:
* builtins.import needs to capture variables like the SourceCode
structure. This means it can not currently be constructed the same
way as other builtins and has special handling, which leaks out to
`eval.rs`. I have postponed dealing with that until we have this
working a bit more.
* the `globals` are not yet passed through
* the error representation for the new variants is absolutely not done
yet, we probably want to switch to something that supports
cause-chaining now (like miette)
* there is no mechanism for emitting warnings at runtime; we need to
add that
Change-Id: I3117a7ae3ff2432bf44f5ff05ad35f47faca31d5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6857
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: wpcarro <wpcarro@gmail.com>
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
This type hides away the lower-level handling of most codemap data
structures, especially to library consumers (see corresponding changes
in tvixbolt).
This will help with implement `import` by giving us central control
over how the codemap works.
Change-Id: Ifcea36776879725871b30c518aeb96ab5fda035a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6855
Tested-by: BuildkiteCI
Reviewed-by: wpcarro <wpcarro@gmail.com>
Until we can display a chained representatino of errors in thunks, it
is most useful to forward the error code from the innermost error to
the user.
Change-Id: I8d67254d52313be40387f080e57966c001e0d51c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6854
Reviewed-by: sterni <sternenseemann@systemli.org>
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This sets up the required logic for finding and merging attribute sets
into nested bindings if they exist. This is absolutely not complete
yet and can, at this commit, probably cause undefined runtime
behaviour if nested attributes are specified.
The basic idea is that a new helper function on the `TrackedBindings`
struct is called with each encountered attribute and determines
whether the new entry can be merged into an existing attribute or not.
Right now the only effect this has in practice is that a new error
becomes available if somebody attempts to cause a merge into an
inherited key.
Change-Id: Id010df3605055eb1ad7fa65241055889dd21bab0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6798
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
As we already have a VM passed to the builtins, we can simply execute
the provided closure/lambda in it for each value.
The primary annoyance with this is that we have to clone the upvalues
for each element, but we can try making this cheaper in the
future (it's also a general problem in the VM itself).
Change-Id: I5bcf56d58c509c0eb081e7cf52f6093216451ce4
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6714
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
TL;DR:
- support `builtins.tail`
- define `ErrorKind::TailEmptyList` and canonical error code
- support basic unit tests
Unsure whether or not the error should be a dedicated `ErrorKind`...
Change-Id: Iae90fda1bb21ce7bdb1aaa2aeb2b8c1e6dcb0f05
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6545
Reviewed-by: wpcarro <wpcarro@gmail.com>
Autosubmit: wpcarro <wpcarro@gmail.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Invalid integers (eg integers that're too long) end up as error returns
on the `.value()` returned from the literal in the AST - previously we'd
unwrap this error, causing it to panic the compiler, but now we've got a
nice error variant for it (which just unwraps the underlying
std::num::ParseIntError).
Change-Id: I50c3c5ba89407d86659e20d8991b9658415f39a0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6635
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
This function is necessary for all builtins that expect some form of
path as an argument. It is merely a wrapper around coerce_to_string that
can shortcut if we already have a path. The absolute path check is done
in the same way as in C++ Nix for compatibility, although it should
probably be revised in the long term (think about Windows, for example).
Since coercing to a path is not an operation possible in the language
directly, this function can live in the builtins module as the only
place it is required.
Change-Id: I69ed5455c00d193fea88b8fa83e28907a761cab5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6574
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Implement C++ Nix's `EvalState::coerceToString` minus some of the Path
/ store handling. This is currently only used for `toString` which does
all possible coercions, but we've already prepared the weaker coercion
variant which is e.g. used for builtins that expect string arguments.
`EvalState::coerceToPath` is still missing for builtins that need a
path, but it'll be easy to build on top of this.
Change-Id: I78d15576b18921791d04b6b1e964b951fdef22c6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6571
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This very closely follows the way it's done for warnings, but errors
have a lot more information available in some cases which we do not
surface yet.
Note also that due to requiring the `CodeMap`, this is not yet called
from eval.rs as the way that is threaded through needs to be
refactored, so only the method for reporting these errors as strings
is implemented so far.
Next steps for this will be to add a generic diagnostics module that
reduces some of the boilerplate for this between warnings & errors,
and which will also give us a good point in the future to switch to a
fancier diagnostics crate.
Change-Id: If6bb209f8e7a568d866e516a90335b9b2afbf66d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6534
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI
It is impossible for tvixbolt to recover from panics, so the user
experience of typing an expression using an unsupported feature was
that it would get sad and stop responding to input.
Instead, raise a normal value-level error of a new variant and
continue where possible.
Change-Id: Ibe016c92cacb87b85095c0f83758eddc6468053e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6528
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
As pointed out by sterni in cl/6205, this is actually possible in
syntactically valid expressions like
{ ${12 + 13} = 12; }
Change-Id: Id8a1e3aceb551f288f9050c4eea563eb6572f1a7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6461
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
As pointed out by grfn on cl/6091
Change-Id: I28308577b7cf99dffb4a4fd3cc8783eb9ab4d0d6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6460
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
With this, if an error occurs while forcing a thunk (which is very
likely) it is threaded through to the top by wrapping it in the
ErrorKind::ThunkForce variant.
We could use this to generate "stacktrace-like" error output if we
wanted, or simply jump through and discard everything except the
innermost error.
Change-Id: I3c1c8708c2f73ae062815adf490ce935b1979da8
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6409
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Previously error spans were optional because the information about
code spans was not available at runtime. Now that this information has
been added, the error type will always carry a span.
This change is very invasive all throughout the codebase. This is due
to the fact that many functions that are called *by* the VM expected
to return `EvalResult`, but this no longer works as the span
information is not available to those functions - only to the VM
itself.
To work around this the majority of these functions have been changed
to return `Result<T, ErrorKind>` instead and an accompanying macro in
the VM constructs the "real" error.
Note that this implementatino currently has a bug where errors
occuring within thunks will yield the location at which the thunk was
forced, not the location at which the error occured within the code.
This will be fixed soon, but the commit is large enough as is.
Change-Id: Ib1ecb81a4d09d464a95ea7ea9e589f3bd08d5202
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6408
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Another step towards being able to report accurate errors. The codemap
spans contain strictly more accessible information, as they now retain
information about which input file something came from.
This required some shuffling around in the compiler to thread all the
right information to the right places.
Change-Id: I18ccfb20f07b0c33e1c4f51ca00cd09f7b2d19c6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6404
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
This operation forces the evaluation of a thunk.
There is some potential here for making an implementation that avoids
some copies, but the thunk machinery is tricky to get right so the
first priority is to make sure it is correct by keeping the
implementation simple.
Change-Id: Ib381455b02f42ded717faff63f55afed4c8fb7e3
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6352
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Nix does not allow things like `let a = 1; a = 2; in a`, but doing it
across depths is allowed.
Change-Id: I6a259f8b01a254b433b58c736e245c9c764641b6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6301
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
These do essentially the same, but return different error variants as
upstream Nix considers `throw` to be (sometimes) catchable.
Change-Id: I1a9ea84567d46fb37287dbf3f3f67052f9382cca
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6259
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Nix functions always have a single argument and we do not yet make
efforts to optimise this in Tvix for known multi-argument functions
being directly applied.
For this reason, the call instruction is fairly simple and just calls
out to construct a new call frame.
Note that the logic for terminating the run loop has moved to the top
of the dispatch; this is because the loop run needs to be skipped if
the call frame for the current lambda has just been dropped.
Change-Id: I259bc07e19c1e55cd0a65207fa8105b23052b967
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6249
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI
Instead of exiting the compiler at the first sight of an error,
skip any erroneous nodes and continue compiling, collecting more
errors along the way.
This paves the way for nicer error reporting in which multiple errors
can be reported at once, avoiding situations in which users are
hunting a fault error-by-error and possibly getting distracted by
less useful output.
Change-Id: I80c9a87272e33a31297167ae2eb2706a46adf15a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6236
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
This starts paving the way for nicer, source-code based error
reporting.
Right now the code paths in the VM do not emit annotated errors, as we
do not yet preserve that structure from the compiler. However, error
emitting code paths in the compiler have been amended to include known
nodes.
Change-Id: I1b74410ffd891c40cd913361bd73c4336ec8aa5b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6235
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Since the latest published version of rnix-parser on crates.io, the
crate has undergone major changes which are only available in the git
repository at the moment. This commit updates the compiler to this
newer version of rnix.
Most notably, the entire AST provided by rnix is now wrapped in the
AST type system. As a result of this traversal is much nicer in many
places, especially for things like nested attribute selection.
There are a handful of smaller features missing for full feature
parity with the previous version, especially handling of path
literals, but PRs for these already exist in rnix-parser.
Change-Id: Icde6d393067976549492b7d89c4cc49e5e575fc7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6231
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
This implements `assert`, which evaluates an expression and aborts
evaluation if the value is not `true`.
At this point we should introduce eval-failed-* tests; probably
asserting against some representation of the error enum?
Change-Id: If54c8f616d89b829c1860a4835dde60a2cd70d7a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6230
Reviewed-by: grfn <grfn@gws.fyi>
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
We're confident that we're handling all branches that can reasonably
occur from valid AST, any other cases should be considered a critical
evaluator bug and panic rather than surfacing something that looks
like user error.
Change-Id: If96966eb32b8ff12fcaeb9ea3b0c8fc51b6abd11
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6205
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI
This makes basic `let ... in ...` statements work correctly. It does
not yet account for the call frames pushed into the VM during function
application.
Change-Id: I67155171daf1a43011b96716dd9d1ab04b27db33
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6190
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Nix does not allow dynamic identifiers in let expressions (only in
attribute sets), but there are several different kinds of things it
considers static identifiers.
The functions introduced here put the path components of a let
expression into normalised (string) form, and surface an error about
dynamic keys if one is encountered.
Change-Id: Ia3ebd95c6f3ed3cd33b94e156930d2e9c39b6cbf
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6189
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
There are multiple things that can theoretically fail while resolving
a path, as some of it includes I/O. A new error variant has been added
for this and appropriate errors have been introduced.
Change-Id: Ie222245425207dabbf203166eb5ed1eec0114483
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6184
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Fairly straightforward, handling the optimised representations
manually and otherwise delegating to BTreeMap.
Note that parsing of raw identifiers is not yet implemented.
Encountering an identifier node usually means that there is locals
access going on, so we need a special case for compiling a node in
such a way that an identifier's literal value ends up on the stack.
Change-Id: I13fbab7ac657b17ef3f4c5859fe737c321890c8a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6158
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: grfn <grfn@gws.fyi>
This is accomplished by simply delegating to the Rust implementations
of (Partial)Ord and (Partial)Eq, which are implemented for Value and
underlying wrapper types to behave like they do in Nix.
To ease the implementation overhead, a new comparison operator macro
has been added to the VM module.
Incomparable types will raise a new error variant when a comparison is
attempted, containing both supplied types. This mimics the information
carried in the error thrown by C++ Nix.
Change-Id: Ia19634d69119d40722f3ca672387bc3a80096998
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6143
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
This can construct non-overlapping nested attribute sets (i.e. `{ a.b
= 1; b.c = 2; }`, but not `{ a.b = 1; a.c = 2; }`).
In order to do the latter, it's necessary to gain the ability to
manipulate the in-progress attribute set construction. There's
multiple different options for this ...
Change-Id: If1a762a720b175e8eb4216cbf96a7434d22640fb
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6106
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
