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use std::borrow::Cow;
use std::cell::RefCell;
use std::collections::hash_map::HashMap;
use std::collections::HashSet;
use std::hash::BuildHasher;
use std::num;
use std::rc::Rc;
use std::sync::atomic::AtomicBool;
use std::sync::Arc;
use syn::{Expr, Lit, Meta};
use crate::ast::NestedMeta;
use crate::util::path_to_string;
use crate::{Error, Result};
/// Create an instance from an item in an attribute declaration.
///
/// # Implementing `FromMeta`
/// * Do not take a dependency on the `ident` of the passed-in meta item. The ident will be set by the field name of the containing struct.
/// * Implement only the `from_*` methods that you intend to support. The default implementations will return useful errors.
///
/// # Provided Implementations
/// ## bool
///
/// * Word with no value specified - becomes `true`.
/// * As a boolean literal, e.g. `foo = true`.
/// * As a string literal, e.g. `foo = "true"`.
///
/// ## char
/// * As a char literal, e.g. `foo = '#'`.
/// * As a string literal consisting of a single character, e.g. `foo = "#"`.
///
/// ## String
/// * As a string literal, e.g. `foo = "hello"`.
/// * As a raw string literal, e.g. `foo = r#"hello "world""#`.
///
/// ## Number
/// * As a string literal, e.g. `foo = "-25"`.
/// * As an unquoted positive value, e.g. `foo = 404`. Negative numbers must be in quotation marks.
///
/// ## ()
/// * Word with no value specified, e.g. `foo`. This is best used with `Option`.
/// See `darling::util::Flag` for a more strongly-typed alternative.
///
/// ## Option
/// * Any format produces `Some`.
///
/// ## `Result<T, darling::Error>`
/// * Allows for fallible parsing; will populate the target field with the result of the
/// parse attempt.
pub trait FromMeta: Sized {
fn from_nested_meta(item: &NestedMeta) -> Result<Self> {
(match *item {
NestedMeta::Lit(ref lit) => Self::from_value(lit),
NestedMeta::Meta(ref mi) => Self::from_meta(mi),
})
.map_err(|e| e.with_span(item))
}
/// Create an instance from a `syn::Meta` by dispatching to the format-appropriate
/// trait function. This generally should not be overridden by implementers.
///
/// # Error Spans
/// If this method is overridden and can introduce errors that weren't passed up from
/// other `from_meta` calls, the override must call `with_span` on the error using the
/// `item` to make sure that the emitted diagnostic points to the correct location in
/// source code.
fn from_meta(item: &Meta) -> Result<Self> {
(match *item {
Meta::Path(_) => Self::from_word(),
Meta::List(ref value) => {
Self::from_list(&NestedMeta::parse_meta_list(value.tokens.clone())?[..])
}
Meta::NameValue(ref value) => Self::from_expr(&value.value),
})
.map_err(|e| e.with_span(item))
}
/// When a field is omitted from a parent meta-item, `from_none` is used to attempt
/// recovery before a missing field error is generated.
///
/// **Most types should not override this method.** `darling` already allows field-level
/// missing-field recovery using `#[darling(default)]` and `#[darling(default = "...")]`,
/// and users who add a `String` field to their `FromMeta`-deriving struct would be surprised
/// if they get back `""` instead of a missing field error when that field is omitted.
///
/// The primary use-case for this is `Option<T>` fields gracefully handlling absence without
/// needing `#[darling(default)]`.
fn from_none() -> Option<Self> {
None
}
/// Create an instance from the presence of the word in the attribute with no
/// additional options specified.
fn from_word() -> Result<Self> {
Err(Error::unsupported_format("word"))
}
/// Create an instance from a list of nested meta items.
#[allow(unused_variables)]
fn from_list(items: &[NestedMeta]) -> Result<Self> {
Err(Error::unsupported_format("list"))
}
/// Create an instance from a literal value of either `foo = "bar"` or `foo("bar")`.
/// This dispatches to the appropriate method based on the type of literal encountered,
/// and generally should not be overridden by implementers.
///
/// # Error Spans
/// If this method is overridden, the override must make sure to add `value`'s span
/// information to the returned error by calling `with_span(value)` on the `Error` instance.
fn from_value(value: &Lit) -> Result<Self> {
(match *value {
Lit::Bool(ref b) => Self::from_bool(b.value),
Lit::Str(ref s) => Self::from_string(&s.value()),
Lit::Char(ref ch) => Self::from_char(ch.value()),
_ => Err(Error::unexpected_lit_type(value)),
})
.map_err(|e| e.with_span(value))
}
fn from_expr(expr: &Expr) -> Result<Self> {
match *expr {
Expr::Lit(ref lit) => Self::from_value(&lit.lit),
Expr::Group(ref group) => {
// syn may generate this invisible group delimiter when the input to the darling
// proc macro (specifically, the attributes) are generated by a
// macro_rules! (e.g. propagating a macro_rules!'s expr)
// Since we want to basically ignore these invisible group delimiters,
// we just propagate the call to the inner expression.
Self::from_expr(&group.expr)
}
_ => Err(Error::unexpected_expr_type(expr)),
}
.map_err(|e| e.with_span(expr))
}
/// Create an instance from a char literal in a value position.
#[allow(unused_variables)]
fn from_char(value: char) -> Result<Self> {
Err(Error::unexpected_type("char"))
}
/// Create an instance from a string literal in a value position.
#[allow(unused_variables)]
fn from_string(value: &str) -> Result<Self> {
Err(Error::unexpected_type("string"))
}
/// Create an instance from a bool literal in a value position.
#[allow(unused_variables)]
fn from_bool(value: bool) -> Result<Self> {
Err(Error::unexpected_type("bool"))
}
}
// FromMeta impls for std and syn types.
impl FromMeta for () {
fn from_word() -> Result<Self> {
Ok(())
}
}
impl FromMeta for bool {
fn from_word() -> Result<Self> {
Ok(true)
}
#[allow(clippy::wrong_self_convention)] // false positive
fn from_bool(value: bool) -> Result<Self> {
Ok(value)
}
fn from_string(value: &str) -> Result<Self> {
value.parse().map_err(|_| Error::unknown_value(value))
}
}
impl FromMeta for AtomicBool {
fn from_meta(mi: &Meta) -> Result<Self> {
FromMeta::from_meta(mi)
.map(AtomicBool::new)
.map_err(|e| e.with_span(mi))
}
}
impl FromMeta for char {
#[allow(clippy::wrong_self_convention)] // false positive
fn from_char(value: char) -> Result<Self> {
Ok(value)
}
fn from_string(s: &str) -> Result<Self> {
let mut chars = s.chars();
let char1 = chars.next();
let char2 = chars.next();
if let (Some(char), None) = (char1, char2) {
Ok(char)
} else {
Err(Error::unexpected_type("string"))
}
}
}
impl FromMeta for String {
fn from_string(s: &str) -> Result<Self> {
Ok(s.to_string())
}
}
impl FromMeta for std::path::PathBuf {
fn from_string(s: &str) -> Result<Self> {
Ok(s.into())
}
}
/// Generate an impl of `FromMeta` that will accept strings which parse to numbers or
/// integer literals.
macro_rules! from_meta_num {
($ty:path) => {
impl FromMeta for $ty {
fn from_string(s: &str) -> Result<Self> {
s.parse().map_err(|_| Error::unknown_value(s))
}
fn from_value(value: &Lit) -> Result<Self> {
(match *value {
Lit::Str(ref s) => Self::from_string(&s.value()),
Lit::Int(ref s) => s.base10_parse::<$ty>().map_err(Error::from),
_ => Err(Error::unexpected_lit_type(value)),
})
.map_err(|e| e.with_span(value))
}
}
};
}
from_meta_num!(u8);
from_meta_num!(u16);
from_meta_num!(u32);
from_meta_num!(u64);
from_meta_num!(u128);
from_meta_num!(usize);
from_meta_num!(i8);
from_meta_num!(i16);
from_meta_num!(i32);
from_meta_num!(i64);
from_meta_num!(i128);
from_meta_num!(isize);
from_meta_num!(num::NonZeroU8);
from_meta_num!(num::NonZeroU16);
from_meta_num!(num::NonZeroU32);
from_meta_num!(num::NonZeroU64);
from_meta_num!(num::NonZeroU128);
from_meta_num!(num::NonZeroUsize);
from_meta_num!(num::NonZeroI8);
from_meta_num!(num::NonZeroI16);
from_meta_num!(num::NonZeroI32);
from_meta_num!(num::NonZeroI64);
from_meta_num!(num::NonZeroI128);
from_meta_num!(num::NonZeroIsize);
/// Generate an impl of `FromMeta` that will accept strings which parse to floats or
/// float literals.
macro_rules! from_meta_float {
($ty:ident) => {
impl FromMeta for $ty {
fn from_string(s: &str) -> Result<Self> {
s.parse().map_err(|_| Error::unknown_value(s))
}
fn from_value(value: &Lit) -> Result<Self> {
(match *value {
Lit::Str(ref s) => Self::from_string(&s.value()),
Lit::Float(ref s) => s.base10_parse::<$ty>().map_err(Error::from),
_ => Err(Error::unexpected_lit_type(value)),
})
.map_err(|e| e.with_span(value))
}
}
};
}
from_meta_float!(f32);
from_meta_float!(f64);
/// Parsing support for punctuated. This attempts to preserve span information
/// when available, but also supports parsing strings with the call site as the
/// emitted span.
impl<T: syn::parse::Parse, P: syn::parse::Parse> FromMeta for syn::punctuated::Punctuated<T, P> {
fn from_value(value: &Lit) -> Result<Self> {
if let Lit::Str(ref ident) = *value {
ident
.parse_with(syn::punctuated::Punctuated::parse_terminated)
.map_err(|_| Error::unknown_lit_str_value(ident))
} else {
Err(Error::unexpected_lit_type(value))
}
}
}
/// Support for arbitrary expressions as values in a meta item.
///
/// For backwards-compatibility to versions of `darling` based on `syn` 1,
/// string literals will be "unwrapped" and their contents will be parsed
/// as an expression.
///
/// See [`util::parse_expr`](crate::util::parse_expr) for functions to provide
/// alternate parsing modes for this type.
impl FromMeta for syn::Expr {
fn from_expr(expr: &Expr) -> Result<Self> {
match expr {
Expr::Lit(syn::ExprLit {
lit: lit @ syn::Lit::Str(_),
..
}) => Self::from_value(lit),
Expr::Group(group) => Self::from_expr(&group.expr), // see FromMeta::from_expr
_ => Ok(expr.clone()),
}
}
fn from_string(value: &str) -> Result<Self> {
syn::parse_str(value).map_err(|_| Error::unknown_value(value))
}
fn from_value(value: &::syn::Lit) -> Result<Self> {
if let ::syn::Lit::Str(ref v) = *value {
v.parse::<syn::Expr>()
.map_err(|_| Error::unknown_lit_str_value(v))
} else {
Err(Error::unexpected_lit_type(value))
}
}
}
/// Parser for paths that supports both quote-wrapped and bare values.
impl FromMeta for syn::Path {
fn from_string(value: &str) -> Result<Self> {
syn::parse_str(value).map_err(|_| Error::unknown_value(value))
}
fn from_value(value: &::syn::Lit) -> Result<Self> {
if let ::syn::Lit::Str(ref v) = *value {
v.parse().map_err(|_| Error::unknown_lit_str_value(v))
} else {
Err(Error::unexpected_lit_type(value))
}
}
fn from_expr(expr: &Expr) -> Result<Self> {
match expr {
Expr::Lit(lit) => Self::from_value(&lit.lit),
Expr::Path(path) => Ok(path.path.clone()),
Expr::Group(group) => Self::from_expr(&group.expr), // see FromMeta::from_expr
_ => Err(Error::unexpected_expr_type(expr)),
}
}
}
impl FromMeta for syn::Ident {
fn from_string(value: &str) -> Result<Self> {
syn::parse_str(value).map_err(|_| Error::unknown_value(value))
}
fn from_value(value: &syn::Lit) -> Result<Self> {
if let syn::Lit::Str(ref v) = *value {
v.parse().map_err(|_| Error::unknown_lit_str_value(v))
} else {
Err(Error::unexpected_lit_type(value))
}
}
fn from_expr(expr: &Expr) -> Result<Self> {
match expr {
Expr::Lit(lit) => Self::from_value(&lit.lit),
// All idents are paths, but not all paths are idents -
// the get_ident() method does additional validation to
// make sure the path is actually an ident.
Expr::Path(path) => match path.path.get_ident() {
Some(ident) => Ok(ident.clone()),
None => Err(Error::unexpected_expr_type(expr)),
},
Expr::Group(group) => Self::from_expr(&group.expr), // see FromMeta::from_expr
_ => Err(Error::unexpected_expr_type(expr)),
}
}
}
/// Adapter for various expression types.
///
/// Prior to syn 2.0, darling supported arbitrary expressions as long as they
/// were wrapped in quotation marks. This was helpful for people writing
/// libraries that needed expressions, but it now creates an ambiguity when
/// parsing a meta item.
///
/// To address this, the macro supports both formats; if it cannot parse the
/// item as an expression of the right type and the passed-in expression is
/// a string literal, it will fall back to parsing the string contents.
macro_rules! from_syn_expr_type {
($ty:path, $variant:ident) => {
impl FromMeta for $ty {
fn from_expr(expr: &syn::Expr) -> Result<Self> {
match expr {
syn::Expr::$variant(body) => Ok(body.clone()),
syn::Expr::Lit(expr_lit) => Self::from_value(&expr_lit.lit),
syn::Expr::Group(group) => Self::from_expr(&group.expr), // see FromMeta::from_expr
_ => Err(Error::unexpected_expr_type(expr)),
}
}
fn from_value(value: &::syn::Lit) -> Result<Self> {
if let syn::Lit::Str(body) = &value {
body.parse::<$ty>()
.map_err(|_| Error::unknown_lit_str_value(body))
} else {
Err(Error::unexpected_lit_type(value))
}
}
}
};
}
from_syn_expr_type!(syn::ExprArray, Array);
from_syn_expr_type!(syn::ExprPath, Path);
/// Adapter from `syn::parse::Parse` to `FromMeta` for items that cannot
/// be expressed in a [`syn::MetaNameValue`].
///
/// This cannot be a blanket impl, due to the `syn::Lit` family's need to handle non-string values.
/// Therefore, we use a macro and a lot of impls.
macro_rules! from_syn_parse {
($ty:path) => {
impl FromMeta for $ty {
fn from_string(value: &str) -> Result<Self> {
syn::parse_str(value).map_err(|_| Error::unknown_value(value))
}
fn from_value(value: &::syn::Lit) -> Result<Self> {
if let ::syn::Lit::Str(ref v) = *value {
v.parse::<$ty>()
.map_err(|_| Error::unknown_lit_str_value(v))
} else {
Err(Error::unexpected_lit_type(value))
}
}
}
};
}
from_syn_parse!(syn::Type);
from_syn_parse!(syn::TypeArray);
from_syn_parse!(syn::TypeBareFn);
from_syn_parse!(syn::TypeGroup);
from_syn_parse!(syn::TypeImplTrait);
from_syn_parse!(syn::TypeInfer);
from_syn_parse!(syn::TypeMacro);
from_syn_parse!(syn::TypeNever);
from_syn_parse!(syn::TypeParam);
from_syn_parse!(syn::TypeParen);
from_syn_parse!(syn::TypePath);
from_syn_parse!(syn::TypePtr);
from_syn_parse!(syn::TypeReference);
from_syn_parse!(syn::TypeSlice);
from_syn_parse!(syn::TypeTraitObject);
from_syn_parse!(syn::TypeTuple);
from_syn_parse!(syn::Visibility);
from_syn_parse!(syn::WhereClause);
macro_rules! from_numeric_array {
($ty:ident) => {
/// Parsing an unsigned integer array, i.e. `example = "[1, 2, 3, 4]"`.
impl FromMeta for Vec<$ty> {
fn from_expr(expr: &syn::Expr) -> Result<Self> {
match expr {
syn::Expr::Array(expr_array) => expr_array
.elems
.iter()
.map(|expr| {
let unexpected = || {
Error::custom("Expected array of unsigned integers").with_span(expr)
};
match expr {
Expr::Lit(lit) => $ty::from_value(&lit.lit),
Expr::Group(group) => match &*group.expr {
Expr::Lit(lit) => $ty::from_value(&lit.lit),
_ => Err(unexpected()),
},
_ => Err(unexpected()),
}
})
.collect::<Result<Vec<$ty>>>(),
syn::Expr::Lit(expr_lit) => Self::from_value(&expr_lit.lit),
syn::Expr::Group(group) => Self::from_expr(&group.expr), // see FromMeta::from_expr
_ => Err(Error::unexpected_expr_type(expr)),
}
}
fn from_value(value: &Lit) -> Result<Self> {
let expr_array = syn::ExprArray::from_value(value)?;
Self::from_expr(&syn::Expr::Array(expr_array))
}
}
};
}
from_numeric_array!(u8);
from_numeric_array!(u16);
from_numeric_array!(u32);
from_numeric_array!(u64);
from_numeric_array!(usize);
impl FromMeta for syn::Lit {
fn from_value(value: &Lit) -> Result<Self> {
Ok(value.clone())
}
}
macro_rules! from_meta_lit {
($impl_ty:path, $lit_variant:path) => {
impl FromMeta for $impl_ty {
fn from_value(value: &Lit) -> Result<Self> {
if let $lit_variant(ref value) = *value {
Ok(value.clone())
} else {
Err(Error::unexpected_lit_type(value))
}
}
}
impl FromMeta for Vec<$impl_ty> {
fn from_list(items: &[NestedMeta]) -> Result<Self> {
items
.iter()
.map(<$impl_ty as FromMeta>::from_nested_meta)
.collect()
}
fn from_value(value: &syn::Lit) -> Result<Self> {
let expr_array = syn::ExprArray::from_value(value)?;
Self::from_expr(&syn::Expr::Array(expr_array))
}
fn from_expr(expr: &syn::Expr) -> Result<Self> {
match expr {
syn::Expr::Array(expr_array) => expr_array
.elems
.iter()
.map(<$impl_ty as FromMeta>::from_expr)
.collect::<Result<Vec<_>>>(),
syn::Expr::Lit(expr_lit) => Self::from_value(&expr_lit.lit),
syn::Expr::Group(g) => Self::from_expr(&g.expr),
_ => Err(Error::unexpected_expr_type(expr)),
}
}
}
};
}
from_meta_lit!(syn::LitInt, Lit::Int);
from_meta_lit!(syn::LitFloat, Lit::Float);
from_meta_lit!(syn::LitStr, Lit::Str);
from_meta_lit!(syn::LitByte, Lit::Byte);
from_meta_lit!(syn::LitByteStr, Lit::ByteStr);
from_meta_lit!(syn::LitChar, Lit::Char);
from_meta_lit!(syn::LitBool, Lit::Bool);
from_meta_lit!(proc_macro2::Literal, Lit::Verbatim);
impl FromMeta for syn::Meta {
fn from_meta(value: &syn::Meta) -> Result<Self> {
Ok(value.clone())
}
}
impl FromMeta for Vec<syn::WherePredicate> {
fn from_string(value: &str) -> Result<Self> {
syn::WhereClause::from_string(&format!("where {}", value))
.map(|c| c.predicates.into_iter().collect())
}
fn from_value(value: &Lit) -> Result<Self> {
if let syn::Lit::Str(s) = value {
syn::WhereClause::from_value(&syn::Lit::Str(syn::LitStr::new(
&format!("where {}", s.value()),
value.span(),
)))
.map(|c| c.predicates.into_iter().collect())
} else {
Err(Error::unexpected_lit_type(value))
}
}
}
impl FromMeta for ident_case::RenameRule {
fn from_string(value: &str) -> Result<Self> {
value.parse().map_err(|_| Error::unknown_value(value))
}
}
impl<T: FromMeta> FromMeta for Option<T> {
fn from_none() -> Option<Self> {
Some(None)
}
fn from_meta(item: &Meta) -> Result<Self> {
FromMeta::from_meta(item).map(Some)
}
}
impl<T: FromMeta> FromMeta for Result<T> {
fn from_none() -> Option<Self> {
T::from_none().map(Ok)
}
// `#[darling(flatten)]` forwards directly to this method, so it's
// necessary to declare it to avoid getting an unsupported format
// error if it's invoked directly.
fn from_list(items: &[NestedMeta]) -> Result<Self> {
Ok(FromMeta::from_list(items))
}
fn from_meta(item: &Meta) -> Result<Self> {
Ok(FromMeta::from_meta(item))
}
}
/// Create an impl that forwards to an inner type `T` for parsing.
macro_rules! smart_pointer_t {
($ty:path, $map_fn:path) => {
impl<T: FromMeta> FromMeta for $ty {
fn from_none() -> Option<Self> {
T::from_none().map($map_fn)
}
// `#[darling(flatten)]` forwards directly to this method, so it's
// necessary to declare it to avoid getting an unsupported format
// error if it's invoked directly.
fn from_list(items: &[NestedMeta]) -> Result<Self> {
FromMeta::from_list(items).map($map_fn)
}
fn from_meta(item: &Meta) -> Result<Self> {
FromMeta::from_meta(item).map($map_fn)
}
}
};
}
smart_pointer_t!(Box<T>, Box::new);
smart_pointer_t!(Rc<T>, Rc::new);
smart_pointer_t!(Arc<T>, Arc::new);
smart_pointer_t!(RefCell<T>, RefCell::new);
/// Parses the meta-item, and in case of error preserves a copy of the input for
/// later analysis.
impl<T: FromMeta> FromMeta for ::std::result::Result<T, Meta> {
fn from_meta(item: &Meta) -> Result<Self> {
T::from_meta(item)
.map(Ok)
.or_else(|_| Ok(Err(item.clone())))
}
}
/// Trait to convert from a path into an owned key for a map.
trait KeyFromPath: Sized {
fn from_path(path: &syn::Path) -> Result<Self>;
fn to_display(&self) -> Cow<'_, str>;
}
impl KeyFromPath for String {
fn from_path(path: &syn::Path) -> Result<Self> {
Ok(path_to_string(path))
}
fn to_display(&self) -> Cow<'_, str> {
Cow::Borrowed(self)
}
}
impl KeyFromPath for syn::Path {
fn from_path(path: &syn::Path) -> Result<Self> {
Ok(path.clone())
}
fn to_display(&self) -> Cow<'_, str> {
Cow::Owned(path_to_string(self))
}
}
impl KeyFromPath for syn::Ident {
fn from_path(path: &syn::Path) -> Result<Self> {
if path.segments.len() == 1
&& path.leading_colon.is_none()
&& path.segments[0].arguments.is_empty()
{
Ok(path.segments[0].ident.clone())
} else {
Err(Error::custom("Key must be an identifier").with_span(path))
}
}
fn to_display(&self) -> Cow<'_, str> {
Cow::Owned(self.to_string())
}
}
macro_rules! hash_map {
($key:ty) => {
impl<V: FromMeta, S: BuildHasher + Default> FromMeta for HashMap<$key, V, S> {
fn from_list(nested: &[NestedMeta]) -> Result<Self> {
// Convert the nested meta items into a sequence of (path, value result) result tuples.
// An outer Err means no (key, value) structured could be found, while an Err in the
// second position of the tuple means that value was rejected by FromMeta.
//
// We defer key conversion into $key so that we don't lose span information in the case
// of String keys; we'll need it for good duplicate key errors later.
let pairs = nested
.iter()
.map(|item| -> Result<(&syn::Path, Result<V>)> {
match *item {
NestedMeta::Meta(ref inner) => {
let path = inner.path();
Ok((
path,
FromMeta::from_meta(inner).map_err(|e| e.at_path(&path)),
))
}
NestedMeta::Lit(_) => Err(Error::unsupported_format("expression")),
}
});
let mut errors = Error::accumulator();
// We need to track seen keys separately from the final map, since a seen key with an
// Err value won't go into the final map but should trigger a duplicate field error.
//
// This is a set of $key rather than Path to avoid the possibility that a key type
// parses two paths of different values to the same key value.
let mut seen_keys = HashSet::with_capacity(nested.len());
// The map to return in the Ok case. Its size will always be exactly nested.len(),
// since otherwise ≥1 field had a problem and the entire map is dropped immediately
// when the function returns `Err`.
let mut map = HashMap::with_capacity_and_hasher(nested.len(), Default::default());
for item in pairs {
if let Some((path, value)) = errors.handle(item) {
let key: $key = match KeyFromPath::from_path(path) {
Ok(k) => k,
Err(e) => {
errors.push(e);
// Surface value errors even under invalid keys
errors.handle(value);
continue;
}
};
let already_seen = seen_keys.contains(&key);
if already_seen {
errors.push(Error::duplicate_field(&key.to_display()).with_span(path));
}
match value {
Ok(_) if already_seen => {}
Ok(val) => {
map.insert(key.clone(), val);
}
Err(e) => {
errors.push(e);
}
}
seen_keys.insert(key);
}
}
errors.finish_with(map)
}
}
};
}
// This is done as a macro rather than a blanket impl to avoid breaking backwards compatibility
// with 0.12.x, while still sharing the same impl.
hash_map!(String);
hash_map!(syn::Ident);
hash_map!(syn::Path);
/// Tests for `FromMeta` implementations. Wherever the word `ignore` appears in test input,
/// it should not be considered by the parsing.
#[cfg(test)]
mod tests {
use std::num::{NonZeroU32, NonZeroU64};
use proc_macro2::TokenStream;
use quote::quote;
use syn::parse_quote;
use crate::{Error, FromMeta, Result};
/// parse a string as a syn::Meta instance.
fn pm(tokens: TokenStream) -> ::std::result::Result<syn::Meta, String> {
let attribute: syn::Attribute = parse_quote!(#[#tokens]);
Ok(attribute.meta)
}
#[track_caller]
fn fm<T: FromMeta>(tokens: TokenStream) -> T {
FromMeta::from_meta(&pm(tokens).expect("Tests should pass well-formed input"))
.expect("Tests should pass valid input")
}
#[test]
fn unit_succeeds() {
fm::<()>(quote!(ignore));
}
#[test]
#[allow(clippy::bool_assert_comparison)]
fn bool_succeeds() {
// word format
assert_eq!(fm::<bool>(quote!(ignore)), true);
// bool literal
assert_eq!(fm::<bool>(quote!(ignore = true)), true);
assert_eq!(fm::<bool>(quote!(ignore = false)), false);
// string literals
assert_eq!(fm::<bool>(quote!(ignore = "true")), true);
assert_eq!(fm::<bool>(quote!(ignore = "false")), false);
}
#[test]
fn char_succeeds() {
// char literal
assert_eq!(fm::<char>(quote!(ignore = '😬')), '😬');
// string literal
assert_eq!(fm::<char>(quote!(ignore = "😬")), '😬');
}
#[test]
fn string_succeeds() {
// cooked form
assert_eq!(&fm::<String>(quote!(ignore = "world")), "world");
// raw form
assert_eq!(&fm::<String>(quote!(ignore = r#"world"#)), "world");
}
#[test]
fn pathbuf_succeeds() {
assert_eq!(
fm::<std::path::PathBuf>(quote!(ignore = r#"C:\"#)),
std::path::PathBuf::from(r#"C:\"#)
);
}
#[test]
#[allow(clippy::float_cmp)] // we want exact equality
fn number_succeeds() {
assert_eq!(fm::<u8>(quote!(ignore = "2")), 2u8);
assert_eq!(fm::<i16>(quote!(ignore = "-25")), -25i16);
assert_eq!(fm::<f64>(quote!(ignore = "1.4e10")), 1.4e10);
}
#[should_panic(expected = "UnknownValue(\"0\")")]
#[test]
fn nonzero_number_fails() {
fm::<NonZeroU64>(quote!(ignore = "0"));
}
#[test]
fn nonzero_number_succeeds() {
assert_eq!(
fm::<NonZeroU32>(quote!(ignore = "2")),
NonZeroU32::new(2).unwrap()
);
}
#[test]
fn int_without_quotes() {
assert_eq!(fm::<u8>(quote!(ignore = 2)), 2u8);
assert_eq!(fm::<u16>(quote!(ignore = 255)), 255u16);
assert_eq!(fm::<u32>(quote!(ignore = 5000)), 5000u32);
// Check that we aren't tripped up by incorrect suffixes
assert_eq!(fm::<u32>(quote!(ignore = 5000i32)), 5000u32);
}
#[test]
fn negative_int_without_quotes() {
assert_eq!(fm::<i8>(quote!(ignore = -2)), -2i8);
assert_eq!(fm::<i32>(quote!(ignore = -255)), -255i32);
}
#[test]
#[allow(clippy::float_cmp)] // we want exact equality
fn float_without_quotes() {
assert_eq!(fm::<f32>(quote!(ignore = 2.)), 2.0f32);
assert_eq!(fm::<f32>(quote!(ignore = 2.0)), 2.0f32);
assert_eq!(fm::<f64>(quote!(ignore = 1.4e10)), 1.4e10f64);
}
#[test]
fn too_large_int_produces_error() {
assert!(fm::<Result<u8>>(quote!(ignore = 2000)).is_err());
}
#[test]
fn meta_succeeds() {
use syn::Meta;
assert_eq!(
fm::<Meta>(quote!(hello(world, today))),
pm(quote!(hello(world, today))).unwrap()
);
}
#[test]
fn hash_map_succeeds() {
use std::collections::HashMap;
let comparison = {
let mut c = HashMap::new();
c.insert("hello".to_string(), true);
c.insert("world".to_string(), false);
c.insert("there".to_string(), true);
c
};
assert_eq!(
fm::<HashMap<String, bool>>(quote!(ignore(hello, world = false, there = "true"))),
comparison
);
}
/// Check that a `HashMap` cannot have duplicate keys, and that the generated error
/// is assigned a span to correctly target the diagnostic message.
#[test]
fn hash_map_duplicate() {
use std::collections::HashMap;
let err: Result<HashMap<String, bool>> =
FromMeta::from_meta(&pm(quote!(ignore(hello, hello = false))).unwrap());
let err = err.expect_err("Duplicate keys in HashMap should error");
assert!(err.has_span());
assert_eq!(err.to_string(), Error::duplicate_field("hello").to_string());
}
#[test]
fn hash_map_multiple_errors() {
use std::collections::HashMap;
let err = HashMap::<String, bool>::from_meta(
&pm(quote!(ignore(hello, hello = 3, hello = false))).unwrap(),
)
.expect_err("Duplicates and bad values should error");
assert_eq!(err.len(), 3);
let errors = err.into_iter().collect::<Vec<_>>();
assert!(errors[0].has_span());
assert!(errors[1].has_span());
assert!(errors[2].has_span());
}
#[test]
fn hash_map_ident_succeeds() {
use std::collections::HashMap;
use syn::parse_quote;
let comparison = {
let mut c = HashMap::<syn::Ident, bool>::new();
c.insert(parse_quote!(first), true);
c.insert(parse_quote!(second), false);
c
};
assert_eq!(
fm::<HashMap<syn::Ident, bool>>(quote!(ignore(first, second = false))),
comparison
);
}
#[test]
fn hash_map_ident_rejects_non_idents() {
use std::collections::HashMap;
let err: Result<HashMap<syn::Ident, bool>> =
FromMeta::from_meta(&pm(quote!(ignore(first, the::second))).unwrap());
err.unwrap_err();
}
#[test]
fn hash_map_path_succeeds() {
use std::collections::HashMap;
use syn::parse_quote;
let comparison = {
let mut c = HashMap::<syn::Path, bool>::new();
c.insert(parse_quote!(first), true);
c.insert(parse_quote!(the::second), false);
c
};
assert_eq!(
fm::<HashMap<syn::Path, bool>>(quote!(ignore(first, the::second = false))),
comparison
);
}
/// Tests that fallible parsing will always produce an outer `Ok` (from `fm`),
/// and will accurately preserve the inner contents.
#[test]
fn darling_result_succeeds() {
fm::<Result<()>>(quote!(ignore)).unwrap();
fm::<Result<()>>(quote!(ignore(world))).unwrap_err();
}
/// Test punctuated
#[test]
fn test_punctuated() {
fm::<syn::punctuated::Punctuated<syn::FnArg, syn::token::Comma>>(quote!(
ignore = "a: u8, b: Type"
));
fm::<syn::punctuated::Punctuated<syn::Expr, syn::token::Comma>>(quote!(ignore = "a, b, c"));
}
#[test]
fn test_expr_array() {
fm::<syn::ExprArray>(quote!(ignore = "[0x1, 0x2]"));
fm::<syn::ExprArray>(quote!(ignore = "[\"Hello World\", \"Test Array\"]"));
}
#[test]
fn test_expr() {
fm::<syn::Expr>(quote!(ignore = "x + y"));
fm::<syn::Expr>(quote!(ignore = "an_object.method_call()"));
fm::<syn::Expr>(quote!(ignore = "{ a_statement(); in_a_block }"));
}
#[test]
fn test_expr_without_quotes() {
fm::<syn::Expr>(quote!(ignore = x + y));
fm::<syn::Expr>(quote!(ignore = an_object.method_call()));
fm::<syn::Expr>(quote!(
ignore = {
a_statement();
in_a_block
}
));
}
#[test]
fn test_expr_path() {
fm::<syn::ExprPath>(quote!(ignore = "std::mem::replace"));
fm::<syn::ExprPath>(quote!(ignore = "x"));
fm::<syn::ExprPath>(quote!(ignore = "example::<Test>"));
}
#[test]
fn test_expr_path_without_quotes() {
fm::<syn::ExprPath>(quote!(ignore = std::mem::replace));
fm::<syn::ExprPath>(quote!(ignore = x));
fm::<syn::ExprPath>(quote!(ignore = example::<Test>));
}
#[test]
fn test_path_without_quotes() {
fm::<syn::Path>(quote!(ignore = std::mem::replace));
fm::<syn::Path>(quote!(ignore = x));
fm::<syn::Path>(quote!(ignore = example::<Test>));
}
#[test]
fn test_number_array() {
assert_eq!(fm::<Vec<u8>>(quote!(ignore = [16, 0xff])), vec![0x10, 0xff]);
assert_eq!(
fm::<Vec<u16>>(quote!(ignore = "[32, 0xffff]")),
vec![0x20, 0xffff]
);
assert_eq!(
fm::<Vec<u32>>(quote!(ignore = "[48, 0xffffffff]")),
vec![0x30, 0xffffffff]
);
assert_eq!(
fm::<Vec<u64>>(quote!(ignore = "[64, 0xffffffffffffffff]")),
vec![0x40, 0xffffffffffffffff]
);
assert_eq!(
fm::<Vec<usize>>(quote!(ignore = "[80, 0xffffffff]")),
vec![0x50, 0xffffffff]
);
}
#[test]
fn test_lit_array() {
fm::<Vec<syn::LitStr>>(quote!(ignore = "[\"Hello World\", \"Test Array\"]"));
fm::<Vec<syn::LitStr>>(quote!(ignore = ["Hello World", "Test Array"]));
fm::<Vec<syn::LitChar>>(quote!(ignore = "['a', 'b', 'c']"));
fm::<Vec<syn::LitBool>>(quote!(ignore = "[true]"));
fm::<Vec<syn::LitStr>>(quote!(ignore = "[]"));
fm::<Vec<syn::LitStr>>(quote!(ignore = []));
fm::<Vec<syn::LitBool>>(quote!(ignore = [true, false]));
}
}