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Auto merge of #8127 - dswij:8090, r=xFrednet
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Fix `enum_variants` FP on prefixes that are not camel-case

closes #8090

Fix FP on `enum_variants` when prefixes are only a substring of a camel-case word. Also adds some util helpers on `str_utils` to help parsing camel-case strings.

This changes how the lint behaves:

1. previously if the Prefix is only a length of 1, it's going to get ignored, i.e. these were previously ignored and now is warned
```rust
enum Foo {
    cFoo,
    cBar,
    cBaz,
}

enum Something {
    CCall,
    CCreate,
    CCryogenize,
}
```

2. non-ascii characters that doesn't have casing will not be split,
```rust
enum NonCaps {
    PrefixXXX,
    PrefixTea,
    PrefixCake,
}
```
will be considered as `PrefixXXX`, `Prefix`, `Prefix`, so this won't lint as opposed to fired previously.

changelog: [`enum_variant_names`] Fix FP when first prefix are only a substring of a camel-case word.

---

 (Edited by `@xFrednet` removed some non ascii characters)
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bors committed Dec 28, 2021
2 parents 526fb6b + b82c9ce commit 56ccd30
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124 changes: 65 additions & 59 deletions clippy_lints/src/enum_variants.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2,8 +2,8 @@

use clippy_utils::diagnostics::{span_lint, span_lint_and_help};
use clippy_utils::source::is_present_in_source;
use clippy_utils::str_utils::{self, count_match_end, count_match_start};
use rustc_hir::{EnumDef, Item, ItemKind};
use clippy_utils::str_utils::{camel_case_split, count_match_end, count_match_start};
use rustc_hir::{EnumDef, Item, ItemKind, Variant};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::source_map::Span;
Expand All @@ -18,6 +18,12 @@ declare_clippy_lint! {
/// 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
/// ```rust
/// enum Cake {
Expand Down Expand Up @@ -120,72 +126,73 @@ impl_lint_pass!(EnumVariantNames => [
MODULE_INCEPTION
]);

fn check_variant(
cx: &LateContext<'_>,
threshold: u64,
def: &EnumDef<'_>,
item_name: &str,
item_name_chars: usize,
span: Span,
) {
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(
cx,
ENUM_VARIANT_NAMES,
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(
cx,
ENUM_VARIANT_NAMES,
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 {
let name = var.ident.name.as_str();
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(
cx,
ENUM_VARIANT_NAMES,
var.span,
"variant name starts with the enum's name",
);
}
if count_match_end(item_name, &name).char_count == item_name_chars {
span_lint(
cx,
ENUM_VARIANT_NAMES,
var.span,
"variant name ends with the enum's name",
);
}
}

let first = &def.variants[0].ident.name.as_str();
let mut pre = &first[..str_utils::camel_case_until(&*first).byte_index];
let mut post = &first[str_utils::camel_case_start(&*first).byte_index..];
let mut pre = camel_case_split(first);
let mut post = pre.clone();
post.reverse();
for var in def.variants {
check_enum_start(cx, item_name, var);
check_enum_end(cx, item_name, var);
let name = var.ident.name.as_str();

let pre_match = count_match_start(pre, &name).byte_count;
pre = &pre[..pre_match];
let pre_camel = str_utils::camel_case_until(pre).byte_index;
pre = &pre[..pre_camel];
while let Some((next, last)) = name[pre.len()..].chars().zip(pre.chars().rev()).next() {
if next.is_numeric() {
return;
}
if next.is_lowercase() {
let last = pre.len() - last.len_utf8();
let last_camel = str_utils::camel_case_until(&pre[..last]);
pre = &pre[..last_camel.byte_index];
} else {
break;
}
}
let variant_split = camel_case_split(&name);

let post_match = count_match_end(post, &name);
let post_end = post.len() - post_match.byte_count;
post = &post[post_end..];
let post_camel = str_utils::camel_case_start(post);
post = &post[post_camel.byte_index..];
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 (pre.is_empty(), post.is_empty()) {
(true, true) => return,
(false, _) => ("pre", pre),
(true, false) => ("post", post),
(false, _) => ("pre", pre.join("")),
(true, false) => {
post.reverse();
("post", post.join(""))
},
};
span_lint_and_help(
cx,
Expand Down Expand Up @@ -233,7 +240,6 @@ impl LateLintPass<'_> for EnumVariantNames {
#[allow(clippy::similar_names)]
fn check_item(&mut self, cx: &LateContext<'_>, item: &Item<'_>) {
let item_name = item.ident.name.as_str();
let item_name_chars = item_name.chars().count();
let item_camel = to_camel_case(&item_name);
if !item.span.from_expansion() && is_present_in_source(cx, item.span) {
if let Some(&(ref mod_name, ref mod_camel)) = self.modules.last() {
Expand Down Expand Up @@ -283,7 +289,7 @@ impl LateLintPass<'_> for EnumVariantNames {
}
if let ItemKind::Enum(ref def, _) = item.kind {
if !(self.avoid_breaking_exported_api && cx.access_levels.is_exported(item.def_id)) {
check_variant(cx, self.threshold, def, &item_name, item_name_chars, item.span);
check_variant(cx, self.threshold, def, &item_name, item.span);
}
}
self.modules.push((item.ident.name, item_camel));
Expand Down
91 changes: 91 additions & 0 deletions clippy_utils/src/str_utils.rs
Original file line number Diff line number Diff line change
Expand Up @@ -68,6 +68,20 @@ pub fn camel_case_until(s: &str) -> StrIndex {
/// ```
#[must_use]
pub fn camel_case_start(s: &str) -> StrIndex {
camel_case_start_from_idx(s, 0)
}

/// Returns `StrIndex` of the last camel-case component of `s[idx..]`.
///
/// ```
/// # use clippy_utils::str_utils::{camel_case_start_from_idx, StrIndex};
/// assert_eq!(camel_case_start_from_idx("AbcDef", 0), StrIndex::new(0, 0));
/// assert_eq!(camel_case_start_from_idx("AbcDef", 1), StrIndex::new(3, 3));
/// assert_eq!(camel_case_start_from_idx("AbcDefGhi", 0), StrIndex::new(0, 0));
/// assert_eq!(camel_case_start_from_idx("AbcDefGhi", 1), StrIndex::new(3, 3));
/// assert_eq!(camel_case_start_from_idx("Abcdefg", 1), StrIndex::new(7, 7));
/// ```
pub fn camel_case_start_from_idx(s: &str, start_idx: usize) -> StrIndex {
let char_count = s.chars().count();
let range = 0..char_count;
let mut iter = range.rev().zip(s.char_indices().rev());
Expand All @@ -78,9 +92,13 @@ pub fn camel_case_start(s: &str) -> StrIndex {
} else {
return StrIndex::new(char_count, s.len());
}

let mut down = true;
let mut last_index = StrIndex::new(char_count, s.len());
for (char_index, (byte_index, c)) in iter {
if byte_index < start_idx {
break;
}
if down {
if c.is_uppercase() {
down = false;
Expand All @@ -98,9 +116,55 @@ pub fn camel_case_start(s: &str) -> StrIndex {
return last_index;
}
}

last_index
}

/// Get the indexes of camel case components of a string `s`
///
/// ```
/// # use clippy_utils::str_utils::{camel_case_indices, StrIndex};
/// assert_eq!(
/// camel_case_indices("AbcDef"),
/// vec![StrIndex::new(0, 0), StrIndex::new(3, 3), StrIndex::new(6, 6)]
/// );
/// assert_eq!(
/// camel_case_indices("abcDef"),
/// vec![StrIndex::new(3, 3), StrIndex::new(6, 6)]
/// );
/// ```
pub fn camel_case_indices(s: &str) -> Vec<StrIndex> {
let mut result = Vec::new();
let mut str_idx = camel_case_start(s);

while str_idx.byte_index < s.len() {
let next_idx = str_idx.byte_index + 1;
result.push(str_idx);
str_idx = camel_case_start_from_idx(s, next_idx);
}
result.push(str_idx);

result
}

/// Split camel case string into a vector of its components
///
/// ```
/// # use clippy_utils::str_utils::{camel_case_split, StrIndex};
/// assert_eq!(camel_case_split("AbcDef"), vec!["Abc", "Def"]);
/// ```
pub fn camel_case_split(s: &str) -> Vec<&str> {
let mut offsets = camel_case_indices(s)
.iter()
.map(|e| e.byte_index)
.collect::<Vec<usize>>();
if offsets[0] != 0 {
offsets.insert(0, 0);
}

offsets.windows(2).map(|w| &s[w[0]..w[1]]).collect()
}

/// Dealing with sting comparison can be complicated, this struct ensures that both the
/// character and byte count are provided for correct indexing.
#[derive(Debug, Default, PartialEq, Eq)]
Expand Down Expand Up @@ -231,4 +295,31 @@ mod test {
fn until_caps() {
assert_eq!(camel_case_until("ABCD"), StrIndex::new(0, 0));
}

#[test]
fn camel_case_start_from_idx_full() {
assert_eq!(camel_case_start_from_idx("AbcDef", 0), StrIndex::new(0, 0));
assert_eq!(camel_case_start_from_idx("AbcDef", 1), StrIndex::new(3, 3));
assert_eq!(camel_case_start_from_idx("AbcDef", 4), StrIndex::new(6, 6));
assert_eq!(camel_case_start_from_idx("AbcDefGhi", 0), StrIndex::new(0, 0));
assert_eq!(camel_case_start_from_idx("AbcDefGhi", 1), StrIndex::new(3, 3));
assert_eq!(camel_case_start_from_idx("Abcdefg", 1), StrIndex::new(7, 7));
}

#[test]
fn camel_case_indices_full() {
assert_eq!(camel_case_indices("Abc\u{f6}\u{f6}DD"), vec![StrIndex::new(7, 9)]);
}

#[test]
fn camel_case_split_full() {
assert_eq!(camel_case_split("A"), vec!["A"]);
assert_eq!(camel_case_split("AbcDef"), vec!["Abc", "Def"]);
assert_eq!(camel_case_split("Abc"), vec!["Abc"]);
assert_eq!(camel_case_split("abcDef"), vec!["abc", "Def"]);
assert_eq!(
camel_case_split("\u{f6}\u{f6}AabABcd"),
vec!["\u{f6}\u{f6}", "Aab", "A", "Bcd"]
);
}
}
6 changes: 6 additions & 0 deletions tests/ui/enum_variants.rs
Original file line number Diff line number Diff line change
Expand Up @@ -145,4 +145,10 @@ enum HIDataRequest {
DeleteUnpubHIData(String),
}

enum North {
Normal,
NoLeft,
NoRight,
}

fn main() {}
38 changes: 25 additions & 13 deletions tests/ui/enum_variants.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,18 @@ LL | cFoo,
|
= note: `-D clippy::enum-variant-names` implied by `-D warnings`

error: all variants have the same prefix: `c`
--> $DIR/enum_variants.rs:14:1
|
LL | / enum Foo {
LL | | cFoo,
LL | | cBar,
LL | | cBaz,
LL | | }
| |_^
|
= help: remove the prefixes and use full paths to the variants instead of glob imports

error: variant name starts with the enum's name
--> $DIR/enum_variants.rs:26:5
|
Expand Down Expand Up @@ -60,25 +72,25 @@ LL | | }
|
= help: remove the prefixes and use full paths to the variants instead of glob imports

error: all variants have the same prefix: `WithOut`
--> $DIR/enum_variants.rs:81:1
error: all variants have the same prefix: `C`
--> $DIR/enum_variants.rs:59:1
|
LL | / enum Seallll {
LL | | WithOutCake,
LL | | WithOutTea,
LL | | WithOut,
LL | / enum Something {
LL | | CCall,
LL | | CCreate,
LL | | CCryogenize,
LL | | }
| |_^
|
= help: remove the prefixes and use full paths to the variants instead of glob imports

error: all variants have the same prefix: `Prefix`
--> $DIR/enum_variants.rs:87:1
error: all variants have the same prefix: `WithOut`
--> $DIR/enum_variants.rs:81:1
|
LL | / enum NonCaps {
LL | | Prefix的,
LL | | PrefixTea,
LL | | PrefixCake,
LL | / enum Seallll {
LL | | WithOutCake,
LL | | WithOutTea,
LL | | WithOut,
LL | | }
| |_^
|
Expand Down Expand Up @@ -108,5 +120,5 @@ LL | | }
|
= help: remove the postfixes and use full paths to the variants instead of glob imports

error: aborting due to 11 previous errors
error: aborting due to 12 previous errors

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