use crate::value::CoercionKind;
use std::path::PathBuf;
use std::rc::Rc;
use std::{fmt::Display, num::ParseIntError};
use codemap::Span;
use codemap_diagnostic::{ColorConfig, Diagnostic, Emitter, Level, SpanLabel, SpanStyle};
use smol_str::SmolStr;
use crate::{SourceCode, Value};
#[derive(Clone, Debug)]
pub enum ErrorKind {
/// These are user-generated errors through builtins.
Throw(String),
Abort(String),
AssertionFailed,
DuplicateAttrsKey {
key: String,
},
/// Attempted to specify an invalid key type (e.g. integer) in a
/// dynamic attribute name.
InvalidAttributeName(Value),
AttributeNotFound {
name: String,
},
/// Attempted to index into a list beyond its boundaries.
IndexOutOfBounds {
index: i64,
},
/// Attempted to call `builtins.tail` on an empty list.
TailEmptyList,
TypeError {
expected: &'static str,
actual: &'static str,
},
Incomparable {
lhs: &'static str,
rhs: &'static str,
},
/// Resolving a user-supplied path literal failed in some way.
PathResolution(String),
/// Dynamic keys are not allowed in some scopes.
DynamicKeyInScope(&'static str),
/// Unknown variable in statically known scope.
UnknownStaticVariable,
/// Unknown variable in dynamic scope (with, rec, ...).
UnknownDynamicVariable(String),
/// User is defining the same variable twice at the same depth.
VariableAlreadyDefined(Span),
/// Attempt to call something that is not callable.
NotCallable(&'static str),
/// Infinite recursion encountered while forcing thunks.
InfiniteRecursion,
ParseErrors(Vec<rnix::parser::ParseError>),
/// An error occured while forcing a thunk, and needs to be
/// chained up.
ThunkForce(Box<Error>),
/// Given type can't be coerced to a string in the respective context
NotCoercibleToString {
from: &'static str,
kind: CoercionKind,
},
/// The given string doesn't represent an absolute path
NotAnAbsolutePath(PathBuf),
/// An error occurred when parsing an integer
ParseIntError(ParseIntError),
/// A negative integer was used as a value representing length.
NegativeLength {
length: i64,
},
// Errors specific to nested attribute sets and merges thereof.
/// Nested attributes can not be merged with an inherited value.
UnmergeableInherit {
name: SmolStr,
},
/// Nested attributes can not be merged with values that are not
/// literal attribute sets.
UnmergeableValue,
/// Tvix failed to read a file from disk for some reason.
ReadFileError {
path: PathBuf,
error: Rc<std::io::Error>,
},
/// Parse errors occured while importing a file.
ImportParseError {
path: PathBuf,
errors: Vec<rnix::parser::ParseError>,
},
/// Compilation errors occured while importing a file.
ImportCompilerError {
path: PathBuf,
errors: Vec<Error>,
},
/// Tvix internal warning for features triggered by users that are
/// not actually implemented yet, and without which eval can not
/// proceed.
NotImplemented(&'static str),
}
impl From<ParseIntError> for ErrorKind {
fn from(e: ParseIntError) -> Self {
Self::ParseIntError(e)
}
}
/// Implementation used if errors occur while forcing thunks (which
/// can potentially be threaded through a few contexts, i.e. nested
/// thunks).
impl From<Error> for ErrorKind {
fn from(e: Error) -> Self {
Self::ThunkForce(Box::new(e))
}
}
#[derive(Clone, Debug)]
pub struct Error {
pub kind: ErrorKind,
pub span: Span,
}
impl Display for Error {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
writeln!(f, "{:?}", self.kind)
}
}
pub type EvalResult<T> = Result<T, Error>;
impl Error {
pub fn fancy_format_str(&self, source: &SourceCode) -> String {
let mut out = vec![];
Emitter::vec(&mut out, Some(&*source.codemap())).emit(&[self.diagnostic()]);
String::from_utf8_lossy(&out).to_string()
}
/// Render a fancy, human-readable output of this error and print
/// it to stderr.
pub fn fancy_format_stderr(&self, source: &SourceCode) {
Emitter::stderr(ColorConfig::Auto, Some(&*source.codemap())).emit(&[self.diagnostic()]);
}
/// Create the optional span label displayed as an annotation on
/// the underlined span of the error.
fn span_label(&self) -> Option<String> {
None
}
/// Create the primary error message displayed to users.
fn message(&self) -> String {
match &self.kind {
ErrorKind::Throw(msg) => format!("error thrown: {}", msg),
ErrorKind::Abort(msg) => format!("evaluation aborted: {}", msg),
ErrorKind::AssertionFailed => "assertion failed".to_string(),
ErrorKind::DuplicateAttrsKey { key } => {
format!("attribute key '{}' already defined", key)
}
ErrorKind::InvalidAttributeName(val) => format!(
"found attribute name '{}' of type '{}', but attribute names must be strings",
val,
val.type_of()
),
ErrorKind::AttributeNotFound { name } => format!(
"attribute with name '{}' could not be found in the set",
name
),
ErrorKind::IndexOutOfBounds { index } => {
format!("list index '{}' is out of bounds", index)
}
ErrorKind::TailEmptyList => "'tail' called on an empty list".to_string(),
ErrorKind::TypeError { expected, actual } => format!(
"expected value of type '{}', but found a '{}'",
expected, actual
),
ErrorKind::Incomparable { lhs, rhs } => {
format!("can not compare a {} with a {}", lhs, rhs)
}
ErrorKind::PathResolution(err) => format!("could not resolve path: {}", err),
ErrorKind::DynamicKeyInScope(scope) => {
format!("dynamically evaluated keys are not allowed in {}", scope)
}
ErrorKind::UnknownStaticVariable => "variable not found".to_string(),
ErrorKind::UnknownDynamicVariable(name) => format!(
r#"variable '{}' could not be found
Note that this occured within a `with`-expression. The problem may be related
to a missing value in the attribute set(s) included via `with`."#,
name
),
ErrorKind::VariableAlreadyDefined(_) => "variable has already been defined".to_string(),
ErrorKind::NotCallable(other_type) => {
format!(
"only functions and builtins can be called, but this is a '{}'",
other_type
)
}
ErrorKind::InfiniteRecursion => "infinite recursion encountered".to_string(),
// TODO(tazjin): these errors should actually end up with
// individual spans etc.
ErrorKind::ParseErrors(errors) => format!("failed to parse Nix code: {:?}", errors),
// TODO(tazjin): trace through the whole chain of thunk
// forcing errors with secondary spans, instead of just
// delegating to the inner error
ErrorKind::ThunkForce(err) => err.message(),
ErrorKind::NotCoercibleToString { kind, from } => {
let kindly = match kind {
CoercionKind::Strong => "strongly",
CoercionKind::Weak => "weakly",
};
let hint = if *from == "set" {
", missing a `__toString` or `outPath` attribute"
} else {
""
};
format!("cannot ({kindly}) coerce {from} to a string{hint}")
}
ErrorKind::NotAnAbsolutePath(given) => {
format!(
"string '{}' does not represent an absolute path",
given.to_string_lossy()
)
}
ErrorKind::ParseIntError(err) => {
format!("invalid integer: {}", err)
}
ErrorKind::NegativeLength { length } => {
format!(
"cannot use a negative integer, {}, for a value representing length",
length
)
}
ErrorKind::UnmergeableInherit { name } => {
format!(
"cannot merge a nested attribute set into the inherited entry '{}'",
name
)
}
ErrorKind::UnmergeableValue => {
"nested attribute sets or keys can only be merged with literal attribute sets"
.into()
}
ErrorKind::ReadFileError { path, error } => {
format!(
"failed to read file '{}': {}",
path.to_string_lossy(),
error
)
}
ErrorKind::ImportParseError { errors, path } => {
format!(
"{} parse errors occured while importing '{}'",
errors.len(),
path.to_string_lossy()
)
}
ErrorKind::ImportCompilerError { errors, path } => {
// TODO: chain display of these errors, though this is
// probably not the right place for that (should
// branch into a more elaborate diagnostic() call
// below).
format!(
"{} errors occured while importing '{}'",
errors.len(),
path.to_string_lossy()
)
}
ErrorKind::NotImplemented(feature) => {
format!("feature not yet implemented in Tvix: {}", feature)
}
}
}
/// Return the unique error code for this variant which can be
/// used to refer users to documentation.
fn code(&self) -> &'static str {
match self.kind {
ErrorKind::Throw(_) => "E001",
ErrorKind::Abort(_) => "E002",
ErrorKind::AssertionFailed => "E003",
ErrorKind::InvalidAttributeName { .. } => "E004",
ErrorKind::AttributeNotFound { .. } => "E005",
ErrorKind::TypeError { .. } => "E006",
ErrorKind::Incomparable { .. } => "E007",
ErrorKind::PathResolution(_) => "E008",
ErrorKind::DynamicKeyInScope(_) => "E009",
ErrorKind::UnknownStaticVariable => "E010",
ErrorKind::UnknownDynamicVariable(_) => "E011",
ErrorKind::VariableAlreadyDefined(_) => "E012",
ErrorKind::NotCallable(_) => "E013",
ErrorKind::InfiniteRecursion => "E014",
ErrorKind::ParseErrors(_) => "E015",
ErrorKind::DuplicateAttrsKey { .. } => "E016",
ErrorKind::NotCoercibleToString { .. } => "E018",
ErrorKind::IndexOutOfBounds { .. } => "E019",
ErrorKind::NotAnAbsolutePath(_) => "E020",
ErrorKind::ParseIntError(_) => "E021",
ErrorKind::NegativeLength { .. } => "E022",
ErrorKind::TailEmptyList { .. } => "E023",
ErrorKind::UnmergeableInherit { .. } => "E024",
ErrorKind::UnmergeableValue => "E025",
ErrorKind::ReadFileError { .. } => "E026",
ErrorKind::ImportParseError { .. } => "E027",
ErrorKind::ImportCompilerError { .. } => "E028",
// Placeholder error while Tvix is under construction.
ErrorKind::NotImplemented(_) => "E999",
// TODO: thunk force errors should yield a chained
// diagnostic, but until then we just forward the error
// code from the inner error.
//
// The error code for thunk forces is E017.
ErrorKind::ThunkForce(ref err) => err.code(),
}
}
fn diagnostic(&self) -> Diagnostic {
let span_label = SpanLabel {
label: self.span_label(),
span: self.span,
style: SpanStyle::Primary,
};
Diagnostic {
level: Level::Error,
message: self.message(),
spans: vec![span_label],
code: Some(self.code().into()),
}
}
}
