rust/clippy_lints/src/item_name_repetitions.rs

454 lines
15 KiB
Rust

use clippy_config::Conf;
use clippy_utils::diagnostics::{span_lint, span_lint_and_help, span_lint_hir};
use clippy_utils::is_bool;
use clippy_utils::macros::span_is_local;
use clippy_utils::source::is_present_in_source;
use clippy_utils::str_utils::{camel_case_split, count_match_end, count_match_start, to_camel_case, to_snake_case};
use rustc_data_structures::fx::FxHashSet;
use rustc_hir::{EnumDef, FieldDef, Item, ItemKind, OwnerId, Variant, VariantData};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::impl_lint_pass;
use rustc_span::symbol::Symbol;
use rustc_span::Span;
declare_clippy_lint! {
/// ### What it does
/// Detects enumeration variants that are prefixed or suffixed
/// by the same characters.
///
/// ### Why is this bad?
/// Enumeration variant names should specify their variant,
/// not repeat the enumeration name.
///
/// ### Limitations
/// Characters with no casing will be considered when comparing prefixes/suffixes
/// This applies to numbers and non-ascii characters without casing
/// e.g. `Foo1` and `Foo2` is considered to have different prefixes
/// (the prefixes are `Foo1` and `Foo2` respectively), as also `Bar螃`, `Bar蟹`
///
/// ### Example
/// ```no_run
/// enum Cake {
/// BlackForestCake,
/// HummingbirdCake,
/// BattenbergCake,
/// }
/// ```
/// Use instead:
/// ```no_run
/// enum Cake {
/// BlackForest,
/// Hummingbird,
/// Battenberg,
/// }
/// ```
#[clippy::version = "pre 1.29.0"]
pub ENUM_VARIANT_NAMES,
style,
"enums where all variants share a prefix/postfix"
}
declare_clippy_lint! {
/// ### What it does
/// Detects type names that are prefixed or suffixed by the
/// containing module's name.
///
/// ### Why is this bad?
/// It requires the user to type the module name twice.
///
/// ### Example
/// ```no_run
/// mod cake {
/// struct BlackForestCake;
/// }
/// ```
///
/// Use instead:
/// ```no_run
/// mod cake {
/// struct BlackForest;
/// }
/// ```
#[clippy::version = "1.33.0"]
pub MODULE_NAME_REPETITIONS,
pedantic,
"type names prefixed/postfixed with their containing module's name"
}
declare_clippy_lint! {
/// ### What it does
/// Checks for modules that have the same name as their
/// parent module
///
/// ### Why is this bad?
/// A typical beginner mistake is to have `mod foo;` and
/// again `mod foo { ..
/// }` in `foo.rs`.
/// The expectation is that items inside the inner `mod foo { .. }` are then
/// available
/// through `foo::x`, but they are only available through
/// `foo::foo::x`.
/// If this is done on purpose, it would be better to choose a more
/// representative module name.
///
/// ### Example
/// ```ignore
/// // lib.rs
/// mod foo;
/// // foo.rs
/// mod foo {
/// ...
/// }
/// ```
#[clippy::version = "pre 1.29.0"]
pub MODULE_INCEPTION,
style,
"modules that have the same name as their parent module"
}
declare_clippy_lint! {
/// ### What it does
/// Detects struct fields that are prefixed or suffixed
/// by the same characters or the name of the struct itself.
///
/// ### Why is this bad?
/// Information common to all struct fields is better represented in the struct name.
///
/// ### Limitations
/// Characters with no casing will be considered when comparing prefixes/suffixes
/// This applies to numbers and non-ascii characters without casing
/// e.g. `foo1` and `foo2` is considered to have different prefixes
/// (the prefixes are `foo1` and `foo2` respectively), as also `bar螃`, `bar蟹`
///
/// ### Example
/// ```no_run
/// struct Cake {
/// cake_sugar: u8,
/// cake_flour: u8,
/// cake_eggs: u8
/// }
/// ```
/// Use instead:
/// ```no_run
/// struct Cake {
/// sugar: u8,
/// flour: u8,
/// eggs: u8
/// }
/// ```
#[clippy::version = "1.75.0"]
pub STRUCT_FIELD_NAMES,
pedantic,
"structs where all fields share a prefix/postfix or contain the name of the struct"
}
pub struct ItemNameRepetitions {
modules: Vec<(Symbol, String, OwnerId)>,
enum_threshold: u64,
struct_threshold: u64,
avoid_breaking_exported_api: bool,
allow_private_module_inception: bool,
allowed_prefixes: FxHashSet<String>,
}
impl ItemNameRepetitions {
pub fn new(conf: &'static Conf) -> Self {
Self {
modules: Vec::new(),
enum_threshold: conf.enum_variant_name_threshold,
struct_threshold: conf.struct_field_name_threshold,
avoid_breaking_exported_api: conf.avoid_breaking_exported_api,
allow_private_module_inception: conf.allow_private_module_inception,
allowed_prefixes: conf.allowed_prefixes.iter().map(|s| to_camel_case(s)).collect(),
}
}
fn is_allowed_prefix(&self, prefix: &str) -> bool {
self.allowed_prefixes.contains(prefix)
}
}
impl_lint_pass!(ItemNameRepetitions => [
ENUM_VARIANT_NAMES,
STRUCT_FIELD_NAMES,
MODULE_NAME_REPETITIONS,
MODULE_INCEPTION
]);
#[must_use]
fn have_no_extra_prefix(prefixes: &[&str]) -> bool {
prefixes.iter().all(|p| p == &"" || p == &"_")
}
fn check_fields(cx: &LateContext<'_>, threshold: u64, item: &Item<'_>, fields: &[FieldDef<'_>]) {
if (fields.len() as u64) < threshold {
return;
}
check_struct_name_repetition(cx, item, fields);
// if the SyntaxContext of the identifiers of the fields and struct differ dont lint them.
// this prevents linting in macros in which the location of the field identifier names differ
if !fields.iter().all(|field| item.ident.span.eq_ctxt(field.ident.span)) {
return;
}
let mut pre: Vec<&str> = match fields.first() {
Some(first_field) => first_field.ident.name.as_str().split('_').collect(),
None => return,
};
let mut post = pre.clone();
post.reverse();
for field in fields {
let field_split: Vec<&str> = field.ident.name.as_str().split('_').collect();
if field_split.len() == 1 {
return;
}
pre = pre
.into_iter()
.zip(field_split.iter())
.take_while(|(a, b)| &a == b)
.map(|e| e.0)
.collect();
post = post
.into_iter()
.zip(field_split.iter().rev())
.take_while(|(a, b)| &a == b)
.map(|e| e.0)
.collect();
}
let prefix = pre.join("_");
post.reverse();
let postfix = match post.last() {
Some(&"") => post.join("_") + "_",
Some(_) | None => post.join("_"),
};
if fields.len() > 1 {
let (what, value) = match (
prefix.is_empty() || prefix.chars().all(|c| c == '_'),
postfix.is_empty(),
) {
(true, true) => return,
(false, _) => ("pre", prefix),
(true, false) => ("post", postfix),
};
if fields.iter().all(|field| is_bool(field.ty)) {
// If all fields are booleans, we don't want to emit this lint.
return;
}
span_lint_and_help(
cx,
STRUCT_FIELD_NAMES,
item.span,
format!("all fields have the same {what}fix: `{value}`"),
None,
format!("remove the {what}fixes"),
);
}
}
fn check_struct_name_repetition(cx: &LateContext<'_>, item: &Item<'_>, fields: &[FieldDef<'_>]) {
let snake_name = to_snake_case(item.ident.name.as_str());
let item_name_words: Vec<&str> = snake_name.split('_').collect();
for field in fields {
if field.ident.span.eq_ctxt(item.ident.span) {
//consider linting only if the field identifier has the same SyntaxContext as the item(struct)
let field_words: Vec<&str> = field.ident.name.as_str().split('_').collect();
if field_words.len() >= item_name_words.len() {
// if the field name is shorter than the struct name it cannot contain it
if field_words.iter().zip(item_name_words.iter()).all(|(a, b)| a == b) {
span_lint_hir(
cx,
STRUCT_FIELD_NAMES,
field.hir_id,
field.span,
"field name starts with the struct's name",
);
}
if field_words.len() > item_name_words.len() {
// lint only if the end is not covered by the start
if field_words
.iter()
.rev()
.zip(item_name_words.iter().rev())
.all(|(a, b)| a == b)
{
span_lint_hir(
cx,
STRUCT_FIELD_NAMES,
field.hir_id,
field.span,
"field name ends with the struct's name",
);
}
}
}
}
}
}
fn check_enum_start(cx: &LateContext<'_>, item_name: &str, variant: &Variant<'_>) {
let name = variant.ident.name.as_str();
let item_name_chars = item_name.chars().count();
if count_match_start(item_name, name).char_count == item_name_chars
&& name.chars().nth(item_name_chars).map_or(false, |c| !c.is_lowercase())
&& name.chars().nth(item_name_chars + 1).map_or(false, |c| !c.is_numeric())
{
span_lint_hir(
cx,
ENUM_VARIANT_NAMES,
variant.hir_id,
variant.span,
"variant name starts with the enum's name",
);
}
}
fn check_enum_end(cx: &LateContext<'_>, item_name: &str, variant: &Variant<'_>) {
let name = variant.ident.name.as_str();
let item_name_chars = item_name.chars().count();
if count_match_end(item_name, name).char_count == item_name_chars {
span_lint_hir(
cx,
ENUM_VARIANT_NAMES,
variant.hir_id,
variant.span,
"variant name ends with the enum's name",
);
}
}
fn check_variant(cx: &LateContext<'_>, threshold: u64, def: &EnumDef<'_>, item_name: &str, span: Span) {
if (def.variants.len() as u64) < threshold {
return;
}
for var in def.variants {
check_enum_start(cx, item_name, var);
check_enum_end(cx, item_name, var);
}
let first = match def.variants.first() {
Some(variant) => variant.ident.name.as_str(),
None => return,
};
let mut pre = camel_case_split(first);
let mut post = pre.clone();
post.reverse();
for var in def.variants {
let name = var.ident.name.as_str();
let variant_split = camel_case_split(name);
if variant_split.len() == 1 {
return;
}
pre = pre
.iter()
.zip(variant_split.iter())
.take_while(|(a, b)| a == b)
.map(|e| *e.0)
.collect();
post = post
.iter()
.zip(variant_split.iter().rev())
.take_while(|(a, b)| a == b)
.map(|e| *e.0)
.collect();
}
let (what, value) = match (have_no_extra_prefix(&pre), post.is_empty()) {
(true, true) => return,
(false, _) => ("pre", pre.join("")),
(true, false) => {
post.reverse();
("post", post.join(""))
},
};
span_lint_and_help(
cx,
ENUM_VARIANT_NAMES,
span,
format!("all variants have the same {what}fix: `{value}`"),
None,
format!(
"remove the {what}fixes and use full paths to \
the variants instead of glob imports"
),
);
}
impl LateLintPass<'_> for ItemNameRepetitions {
fn check_item_post(&mut self, _cx: &LateContext<'_>, _item: &Item<'_>) {
let last = self.modules.pop();
assert!(last.is_some());
}
fn check_item(&mut self, cx: &LateContext<'_>, item: &Item<'_>) {
let item_name = item.ident.name.as_str();
let item_camel = to_camel_case(item_name);
if !item.span.from_expansion() && is_present_in_source(cx, item.span) {
if let [.., (mod_name, mod_camel, owner_id)] = &*self.modules {
// constants don't have surrounding modules
if !mod_camel.is_empty() {
if mod_name == &item.ident.name
&& let ItemKind::Mod(..) = item.kind
&& (!self.allow_private_module_inception || cx.tcx.visibility(owner_id.def_id).is_public())
{
span_lint(
cx,
MODULE_INCEPTION,
item.span,
"module has the same name as its containing module",
);
}
// The `module_name_repetitions` lint should only trigger if the item has the module in its
// name. Having the same name is accepted.
if cx.tcx.visibility(item.owner_id).is_public() && item_camel.len() > mod_camel.len() {
let matching = count_match_start(mod_camel, &item_camel);
let rmatching = count_match_end(mod_camel, &item_camel);
let nchars = mod_camel.chars().count();
let is_word_beginning = |c: char| c == '_' || c.is_uppercase() || c.is_numeric();
if matching.char_count == nchars {
match item_camel.chars().nth(nchars) {
Some(c) if is_word_beginning(c) => span_lint(
cx,
MODULE_NAME_REPETITIONS,
item.ident.span,
"item name starts with its containing module's name",
),
_ => (),
}
}
if rmatching.char_count == nchars
&& !self.is_allowed_prefix(&item_camel[..item_camel.len() - rmatching.byte_count])
{
span_lint(
cx,
MODULE_NAME_REPETITIONS,
item.ident.span,
"item name ends with its containing module's name",
);
}
}
}
}
}
if !(self.avoid_breaking_exported_api && cx.effective_visibilities.is_exported(item.owner_id.def_id))
&& span_is_local(item.span)
{
match item.kind {
ItemKind::Enum(def, _) => check_variant(cx, self.enum_threshold, &def, item_name, item.span),
ItemKind::Struct(VariantData::Struct { fields, .. }, _) => {
check_fields(cx, self.struct_threshold, item, fields);
},
_ => (),
}
}
self.modules.push((item.ident.name, item_camel, item.owner_id));
}
}