tvl-depot/tvix/eval/src/warnings.rs
Vincent Ambo e86acd3212 feat(tvix/eval): implement legacy let syntax
... and emit a warning if anyone decides to use.

Change-Id: Iaa6fe9fa932340e6d0fa9f357155e78823702576
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6611
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-16 18:13:26 +00:00

116 lines
3.9 KiB
Rust

//! Implements warnings that are emitted in cases where code passed to
//! Tvix exhibits problems that the user could address.
use codemap::CodeMap;
use codemap_diagnostic::{ColorConfig, Diagnostic, Emitter, Level, SpanLabel, SpanStyle};
#[derive(Debug)]
pub enum WarningKind {
DeprecatedLiteralURL,
UselessInherit,
UnusedBinding,
ShadowedGlobal(&'static str),
DeprecatedLegacyLet,
/// Tvix internal warning for features triggered by users that are
/// not actually implemented yet, but do not cause runtime failures.
NotImplemented(&'static str),
}
#[derive(Debug)]
pub struct EvalWarning {
pub kind: WarningKind,
pub span: codemap::Span,
}
impl EvalWarning {
/// Render a fancy, human-readable output of this warning and
/// return it as a String. Note that this version of the output
/// does not include any colours or font styles.
pub fn fancy_format_str(&self, codemap: &CodeMap) -> String {
let mut out = vec![];
Emitter::vec(&mut out, Some(codemap)).emit(&[self.diagnostic(codemap)]);
String::from_utf8_lossy(&out).to_string()
}
/// Render a fancy, human-readable output of this warning and
/// print it to stderr. If rendered in a terminal that supports
/// colours and font styles, the output will include those.
pub fn fancy_format_stderr(&self, codemap: &CodeMap) {
Emitter::stderr(ColorConfig::Auto, Some(codemap)).emit(&[self.diagnostic(codemap)]);
}
/// Create the optional span label displayed as an annotation on
/// the underlined span of the warning.
fn span_label(&self) -> Option<String> {
match self.kind {
WarningKind::UnusedBinding | WarningKind::ShadowedGlobal(_) => {
Some("variable declared here".into())
}
_ => None,
}
}
/// Create the primary warning message displayed to users for a
/// warning.
fn message(&self, codemap: &CodeMap) -> String {
match self.kind {
WarningKind::DeprecatedLiteralURL => {
"URL literal syntax is deprecated, use a quoted string instead".to_string()
}
WarningKind::UselessInherit => {
"inherited variable already exists with the same value".to_string()
}
WarningKind::UnusedBinding => {
let file = codemap.find_file(self.span.low());
format!(
"variable '{}' is declared, but never used:",
file.source_slice(self.span)
)
}
WarningKind::ShadowedGlobal(name) => {
format!("declared variable '{}' shadows a built-in global!", name)
}
WarningKind::DeprecatedLegacyLet => {
"legacy `let` syntax used, please rewrite this as `let .. in ...`".to_string()
}
WarningKind::NotImplemented(what) => {
format!("feature not yet implemented in tvix: {}", what)
}
}
}
/// Return the unique warning code for this variant which can be
/// used to refer users to documentation.
fn code(&self) -> &'static str {
match self.kind {
WarningKind::DeprecatedLiteralURL => "W001",
WarningKind::UselessInherit => "W002",
WarningKind::UnusedBinding => "W003",
WarningKind::ShadowedGlobal(_) => "W004",
WarningKind::DeprecatedLegacyLet => "W005",
WarningKind::NotImplemented(_) => "W999",
}
}
fn diagnostic(&self, codemap: &CodeMap) -> Diagnostic {
let span_label = SpanLabel {
label: self.span_label(),
span: self.span,
style: SpanStyle::Primary,
};
Diagnostic {
level: Level::Warning,
message: self.message(codemap),
spans: vec![span_label],
code: Some(self.code().into()),
}
}
}