add new lint tabs in doc comments

This commit is contained in:
Florian Rohm 2019-11-15 16:18:08 +01:00
parent b4f1769734
commit f8f7800b18
4 changed files with 315 additions and 0 deletions

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use crate::utils::span_lint_and_sugg;
use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
use rustc::{declare_lint_pass, declare_tool_lint};
use rustc_errors::Applicability;
use std::convert::TryFrom;
use syntax::ast;
use syntax::source_map::{BytePos, Span};
declare_clippy_lint! {
/// **What it does:** Checks doc comments for usage of tab characters.
///
/// **Why is this bad?** The rust style-guide promotes spaces instead of tabs for indentation.
/// To keep a consistent view on the source, also doc comments should not have tabs.
/// Also, explaining ascii-diagrams containing tabs can get displayed incorrectly when the
/// display settings of the author and reader differ.
///
/// **Known problems:** None.
///
/// **Example:**
/// ```rust
/// ///
/// /// Struct to hold two strings:
/// /// - first one
/// /// - second one
/// pub struct DoubleString {
/// ///
/// /// - First String:
/// /// - needs to be inside here
/// first_string: String,
/// ///
/// /// - Second String:
/// /// - needs to be inside here
/// second_string: String,
///}
/// ```
///
/// Will be converted to:
/// ```rust
/// ///
/// /// Struct to hold two strings:
/// /// - first one
/// /// - second one
/// pub struct DoubleString {
/// ///
/// /// - First String:
/// /// - needs to be inside here
/// first_string: String,
/// ///
/// /// - Second String:
/// /// - needs to be inside here
/// second_string: String,
///}
/// ```
pub TABS_IN_DOC_COMMENTS,
style,
"using tabs in doc comments is not recommended"
}
declare_lint_pass!(TabsInDocComments => [TABS_IN_DOC_COMMENTS]);
impl TabsInDocComments {
fn warn_if_tabs_in_doc(cx: &EarlyContext<'_>, attr: &ast::Attribute) {
if let ast::AttrKind::DocComment(comment) = attr.kind {
let comment = comment.as_str();
for (lo, hi) in get_chunks_of_tabs(&comment) {
let new_span = Span::new(
attr.span.lo() + BytePos(lo),
attr.span.lo() + BytePos(hi),
attr.span.ctxt(),
);
span_lint_and_sugg(
cx,
TABS_IN_DOC_COMMENTS,
new_span,
"using tabs in doc comments is not recommended",
"consider using four spaces per tab",
" ".repeat((hi - lo) as usize),
Applicability::MaybeIncorrect,
);
}
}
}
}
impl EarlyLintPass for TabsInDocComments {
fn check_attribute(&mut self, cx: &EarlyContext<'_>, attribute: &ast::Attribute) {
Self::warn_if_tabs_in_doc(cx, &attribute);
}
}
///
/// scans the string for groups of tabs and returns the start(inclusive) and end positions
/// (exclusive) of all groups
/// e.g. "sd\tasd\t\taa" will be converted to [(2, 3), (6, 8)] as
/// 012 3456 7 89
/// ^-^ ^---^
fn get_chunks_of_tabs(the_str: &str) -> Vec<(u32, u32)> {
let line_length_way_to_long = "doc comment longer than 2^32 chars";
let mut spans: Vec<(u32, u32)> = vec![];
let mut current_start: u32 = 0;
// tracker to decide if the last group of tabs is not closed by a non-tab character
let mut is_active = false;
let chars_array: Vec<_> = the_str.chars().collect();
if chars_array == vec!['\t'] {
return vec![(0, 1)];
}
for (index, arr) in chars_array.windows(2).enumerate() {
let index = u32::try_from(index).expect(line_length_way_to_long);
match arr {
['\t', '\t'] => {
// either string starts with double tab, then we have to set it active,
// otherwise is_active is true anyway
is_active = true;
},
[_, '\t'] => {
// as ['\t', '\t'] is excluded, this has to be a start of a tab group,
// set indices accordingly
is_active = true;
current_start = index + 1;
},
['\t', _] => {
// this now has to be an end of the group, hence we have to push a new tuple
is_active = false;
spans.push((current_start, index + 1));
},
_ => {},
}
}
// only possible when tabs are at the end, insert last group
if is_active {
spans.push((
current_start,
u32::try_from(the_str.chars().count()).expect(line_length_way_to_long),
));
}
spans
}
#[cfg(test)]
mod tests_for_get_chunks_of_tabs {
use super::get_chunks_of_tabs;
#[test]
fn test_empty_string() {
let res = get_chunks_of_tabs("");
assert_eq!(res, vec![]);
}
#[test]
fn test_simple() {
let res = get_chunks_of_tabs("sd\t\t\taa");
assert_eq!(res, vec![(2, 5)]);
}
#[test]
fn test_only_t() {
let res = get_chunks_of_tabs("\t\t");
assert_eq!(res, vec![(0, 2)]);
}
#[test]
fn test_only_one_t() {
let res = get_chunks_of_tabs("\t");
assert_eq!(res, vec![(0, 1)]);
}
#[test]
fn test_double() {
let res = get_chunks_of_tabs("sd\tasd\t\taa");
assert_eq!(res, vec![(2, 3), (6, 8)]);
}
#[test]
fn test_start() {
let res = get_chunks_of_tabs("\t\taa");
assert_eq!(res, vec![(0, 2)]);
}
#[test]
fn test_end() {
let res = get_chunks_of_tabs("aa\t\t");
assert_eq!(res, vec![(2, 4)]);
}
#[test]
fn test_start_single() {
let res = get_chunks_of_tabs("\taa");
assert_eq!(res, vec![(0, 1)]);
}
#[test]
fn test_end_single() {
let res = get_chunks_of_tabs("aa\t");
assert_eq!(res, vec![(2, 3)]);
}
#[test]
fn test_no_tabs() {
let res = get_chunks_of_tabs("dsfs");
assert_eq!(res, vec![]);
}
}

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// run-rustfix
#![warn(clippy::tabs_in_doc_comments)]
#[allow(dead_code)]
///
/// Struct to hold two strings:
/// - first one
/// - second one
pub struct DoubleString {
///
/// - First String:
/// - needs to be inside here
first_string: String,
///
/// - Second String:
/// - needs to be inside here
second_string: String,
}
/// This is main
fn main() {}

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// run-rustfix
#![warn(clippy::tabs_in_doc_comments)]
#[allow(dead_code)]
///
/// Struct to hold two strings:
/// - first one
/// - second one
pub struct DoubleString {
///
/// - First String:
/// - needs to be inside here
first_string: String,
///
/// - Second String:
/// - needs to be inside here
second_string: String,
}
/// This is main
fn main() {}

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error: using tabs in doc comments is not recommended
--> $DIR/tabs_in_doc_comments.rs:12:9
|
LL | /// - First String:
| ^^^^ help: consider using four spaces per tab
|
= note: `-D clippy::tabs-in-doc-comments` implied by `-D warnings`
error: using tabs in doc comments is not recommended
--> $DIR/tabs_in_doc_comments.rs:13:9
|
LL | /// - needs to be inside here
| ^^^^^^^^ help: consider using four spaces per tab
error: using tabs in doc comments is not recommended
--> $DIR/tabs_in_doc_comments.rs:16:9
|
LL | /// - Second String:
| ^^^^ help: consider using four spaces per tab
error: using tabs in doc comments is not recommended
--> $DIR/tabs_in_doc_comments.rs:17:9
|
LL | /// - needs to be inside here
| ^^^^^^^^ help: consider using four spaces per tab
error: using tabs in doc comments is not recommended
--> $DIR/tabs_in_doc_comments.rs:8:5
|
LL | /// - first one
| ^^^^ help: consider using four spaces per tab
error: using tabs in doc comments is not recommended
--> $DIR/tabs_in_doc_comments.rs:8:13
|
LL | /// - first one
| ^^^^^^^^ help: consider using four spaces per tab
error: using tabs in doc comments is not recommended
--> $DIR/tabs_in_doc_comments.rs:9:5
|
LL | /// - second one
| ^^^^ help: consider using four spaces per tab
error: using tabs in doc comments is not recommended
--> $DIR/tabs_in_doc_comments.rs:9:14
|
LL | /// - second one
| ^^^^ help: consider using four spaces per tab
error: aborting due to 8 previous errors