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Add BTreeMap to the HASHMAP_ENTRY rule

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Fixes #433
This commit is contained in:
mcarton 2016-01-12 20:23:28 +01:00
parent e24730cb84
commit 09129c1b41
5 changed files with 58 additions and 42 deletions
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2
README.md
View File

@ -32,7 +32,6 @@ name
[explicit_iter_loop](https://github.com/Manishearth/rust-clippy/wiki#explicit_iter_loop) | warn | for-looping over `_.iter()` or `_.iter_mut()` when `&_` or `&mut _` would do
[filter_next](https://github.com/Manishearth/rust-clippy/wiki#filter_next) | warn | using `filter(p).next()`, which is more succinctly expressed as `.find(p)`
[float_cmp](https://github.com/Manishearth/rust-clippy/wiki#float_cmp) | warn | using `==` or `!=` on float values (as floating-point operations usually involve rounding errors, it is always better to check for approximate equality within small bounds)
[hashmap_entry](https://github.com/Manishearth/rust-clippy/wiki#hashmap_entry) | warn | use of `contains_key` followed by `insert` on a `HashMap`
[identity_op](https://github.com/Manishearth/rust-clippy/wiki#identity_op) | warn | using identity operations, e.g. `x + 0` or `y / 1`
[ineffective_bit_mask](https://github.com/Manishearth/rust-clippy/wiki#ineffective_bit_mask) | warn | expressions where a bit mask will be rendered useless by a comparison, e.g. `(x | 1) > 2`
[inline_always](https://github.com/Manishearth/rust-clippy/wiki#inline_always) | warn | `#[inline(always)]` is a bad idea in most cases
@ -43,6 +42,7 @@ name
[let_unit_value](https://github.com/Manishearth/rust-clippy/wiki#let_unit_value) | warn | creating a let binding to a value of unit type, which usually can't be used afterwards
[linkedlist](https://github.com/Manishearth/rust-clippy/wiki#linkedlist) | warn | usage of LinkedList, usually a vector is faster, or a more specialized data structure like a VecDeque
[map_clone](https://github.com/Manishearth/rust-clippy/wiki#map_clone) | warn | using `.map(|x| x.clone())` to clone an iterator or option's contents (recommends `.cloned()` instead)
[map_entry](https://github.com/Manishearth/rust-clippy/wiki#map_entry) | warn | use of `contains_key` followed by `insert` on a `HashMap` or `BTreeMap`
[match_bool](https://github.com/Manishearth/rust-clippy/wiki#match_bool) | warn | a match on boolean expression; recommends `if..else` block instead
[match_overlapping_arm](https://github.com/Manishearth/rust-clippy/wiki#match_overlapping_arm) | warn | a match has overlapping arms
[match_ref_pats](https://github.com/Manishearth/rust-clippy/wiki#match_ref_pats) | warn | a match or `if let` has all arms prefixed with `&`; the match expression can be dereferenced instead

67
src/hashmap.rs → src/entry.rs
View File

@ -2,11 +2,12 @@ use rustc::lint::*;
use rustc_front::hir::*;
use syntax::codemap::Span;
use utils::{get_item_name, is_exp_equal, match_type, snippet, span_help_and_lint, walk_ptrs_ty};
use utils::HASHMAP_PATH;
use utils::{BTREEMAP_PATH, HASHMAP_PATH};
/// **What it does:** This lint checks for uses of `contains_key` + `insert` on `HashMap`.
/// **What it does:** This lint checks for uses of `contains_key` + `insert` on `HashMap` or
/// `BTreeMap`.
///
/// **Why is this bad?** Using `HashMap::entry` is more efficient.
/// **Why is this bad?** Using `entry` is more efficient.
///
/// **Known problems:** Some false negatives, eg.:
/// ```
@ -23,9 +24,9 @@ use utils::HASHMAP_PATH;
/// m.entry(k).or_insert(v);
/// ```
declare_lint! {
pub HASHMAP_ENTRY,
pub MAP_ENTRY,
Warn,
"use of `contains_key` followed by `insert` on a `HashMap`"
"use of `contains_key` followed by `insert` on a `HashMap` or `BTreeMap`"
}
#[derive(Copy,Clone)]
@ -33,7 +34,7 @@ pub struct HashMapLint;
impl LintPass for HashMapLint {
fn get_lints(&self) -> LintArray {
lint_array!(HASHMAP_ENTRY)
lint_array!(MAP_ENTRY)
}
}
@ -55,17 +56,25 @@ impl LateLintPass for HashMapLint {
let map = &params[0];
let obj_ty = walk_ptrs_ty(cx.tcx.expr_ty(map));
if match_type(cx, obj_ty, &HASHMAP_PATH) {
let sole_expr = if then.expr.is_some() { 1 } else { 0 } + then.stmts.len() == 1;
let kind = if match_type(cx, obj_ty, &BTREEMAP_PATH) {
"BTreeMap"
}
else if match_type(cx, obj_ty, &HASHMAP_PATH) {
"HashMap"
}
else {
return
};
if let Some(ref then) = then.expr {
check_for_insert(cx, expr.span, map, key, then, sole_expr);
}
let sole_expr = if then.expr.is_some() { 1 } else { 0 } + then.stmts.len() == 1;
for stmt in &then.stmts {
if let StmtSemi(ref stmt, _) = stmt.node {
check_for_insert(cx, expr.span, map, key, stmt, sole_expr);
}
if let Some(ref then) = then.expr {
check_for_insert(cx, expr.span, map, key, then, sole_expr, kind);
}
for stmt in &then.stmts {
if let StmtSemi(ref stmt, _) = stmt.node {
check_for_insert(cx, expr.span, map, key, stmt, sole_expr, kind);
}
}
}
@ -73,7 +82,7 @@ impl LateLintPass for HashMapLint {
}
}
fn check_for_insert(cx: &LateContext, span: Span, map: &Expr, key: &Expr, expr: &Expr, sole_expr: bool) {
fn check_for_insert(cx: &LateContext, span: Span, map: &Expr, key: &Expr, expr: &Expr, sole_expr: bool, kind: &str) {
if_let_chain! {
[
let ExprMethodCall(ref name, _, ref params) = expr.node,
@ -82,21 +91,21 @@ fn check_for_insert(cx: &LateContext, span: Span, map: &Expr, key: &Expr, expr:
get_item_name(cx, map) == get_item_name(cx, &*params[0]),
is_exp_equal(cx, key, &params[1])
], {
if sole_expr {
span_help_and_lint(cx, HASHMAP_ENTRY, span,
"usage of `contains_key` followed by `insert` on `HashMap`",
&format!("Consider using `{}.entry({}).or_insert({})`",
snippet(cx, map.span, ".."),
snippet(cx, params[1].span, ".."),
snippet(cx, params[2].span, "..")));
let help = if sole_expr {
format!("Consider using `{}.entry({}).or_insert({})`",
snippet(cx, map.span, ".."),
snippet(cx, params[1].span, ".."),
snippet(cx, params[2].span, ".."))
}
else {
span_help_and_lint(cx, HASHMAP_ENTRY, span,
"usage of `contains_key` followed by `insert` on `HashMap`",
&format!("Consider using `{}.entry({})`",
snippet(cx, map.span, ".."),
snippet(cx, params[1].span, "..")));
}
format!("Consider using `{}.entry({})`",
snippet(cx, map.span, ".."),
snippet(cx, params[1].span, ".."))
};
span_help_and_lint(cx, MAP_ENTRY, span,
&format!("usage of `contains_key` followed by `insert` on `{}`", kind),
&help);
}
}
}

6
src/lib.rs
View File

@ -71,7 +71,7 @@ pub mod temporary_assignment;
pub mod transmute;
pub mod cyclomatic_complexity;
pub mod escape;
pub mod hashmap;
pub mod entry;
pub mod misc_early;
pub mod array_indexing;
pub mod panic;
@ -113,7 +113,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
reg.register_late_lint_pass(box types::UnitCmp);
reg.register_late_lint_pass(box loops::LoopsPass);
reg.register_late_lint_pass(box lifetimes::LifetimePass);
reg.register_late_lint_pass(box hashmap::HashMapLint);
reg.register_late_lint_pass(box entry::HashMapLint);
reg.register_late_lint_pass(box ranges::StepByZero);
reg.register_late_lint_pass(box types::CastPass);
reg.register_late_lint_pass(box types::TypeComplexityPass);
@ -167,10 +167,10 @@ pub fn plugin_registrar(reg: &mut Registry) {
block_in_if_condition::BLOCK_IN_IF_CONDITION_STMT,
collapsible_if::COLLAPSIBLE_IF,
cyclomatic_complexity::CYCLOMATIC_COMPLEXITY,
entry::MAP_ENTRY,
eq_op::EQ_OP,
escape::BOXED_LOCAL,
eta_reduction::REDUNDANT_CLOSURE,
hashmap::HASHMAP_ENTRY,
identity_op::IDENTITY_OP,
len_zero::LEN_WITHOUT_IS_EMPTY,
len_zero::LEN_ZERO,

15
src/utils.rs
View File

@ -19,17 +19,18 @@ use std::ops::{Deref, DerefMut};
pub type MethodArgs = HirVec<P<Expr>>;
// module DefPaths for certain structs/enums we check for
pub const BEGIN_UNWIND: [&'static str; 3] = ["std", "rt", "begin_unwind"];
pub const BTREEMAP_PATH: [&'static str; 4] = ["collections", "btree", "map", "BTreeMap"];
pub const CLONE_PATH: [&'static str; 2] = ["Clone", "clone"];
pub const COW_PATH: [&'static str; 3] = ["collections", "borrow", "Cow"];
pub const HASHMAP_PATH: [&'static str; 5] = ["std", "collections", "hash", "map", "HashMap"];
pub const LL_PATH: [&'static str; 3] = ["collections", "linked_list", "LinkedList"];
pub const MUTEX_PATH: [&'static str; 4] = ["std", "sync", "mutex", "Mutex"];
pub const OPEN_OPTIONS_PATH: [&'static str; 3] = ["std", "fs", "OpenOptions"];
pub const OPTION_PATH: [&'static str; 3] = ["core", "option", "Option"];
pub const RESULT_PATH: [&'static str; 3] = ["core", "result", "Result"];
pub const STRING_PATH: [&'static str; 3] = ["collections", "string", "String"];
pub const VEC_PATH: [&'static str; 3] = ["collections", "vec", "Vec"];
pub const LL_PATH: [&'static str; 3] = ["collections", "linked_list", "LinkedList"];
pub const HASHMAP_PATH: [&'static str; 5] = ["std", "collections", "hash", "map", "HashMap"];
pub const OPEN_OPTIONS_PATH: [&'static str; 3] = ["std", "fs", "OpenOptions"];
pub const MUTEX_PATH: [&'static str; 4] = ["std", "sync", "mutex", "Mutex"];
pub const CLONE_PATH: [&'static str; 2] = ["Clone", "clone"];
pub const BEGIN_UNWIND: [&'static str; 3] = ["std", "rt", "begin_unwind"];
pub const COW_PATH: [&'static str; 3] = ["collections", "borrow", "Cow"];
/// Produce a nested chain of if-lets and ifs from the patterns:
///

10
tests/compile-fail/hashmap.rs → tests/compile-fail/entry.rs
View File

@ -2,9 +2,9 @@
#![plugin(clippy)]
#![allow(unused)]
#![deny(hashmap_entry)]
#![deny(map_entry)]
use std::collections::HashMap;
use std::collections::{BTreeMap, HashMap};
use std::hash::Hash;
fn foo() {}
@ -33,6 +33,12 @@ fn insert_if_absent3<K: Eq + Hash, V>(m: &mut HashMap<K, V>, k: K, v: V) {
//~^^HELP: Consider using `m.entry(k)`
}
fn insert_in_btreemap<K: Ord, V>(m: &mut BTreeMap<K, V>, k: K, v: V) {
if !m.contains_key(&k) { foo(); m.insert(k, v) } else { None };
//~^ERROR: usage of `contains_key` followed by `insert` on `BTreeMap`
//~^^HELP: Consider using `m.entry(k)`
}
fn insert_other_if_absent<K: Eq + Hash, V>(m: &mut HashMap<K, V>, k: K, o: K, v: V) {
if !m.contains_key(&k) { m.insert(o, v); }
}