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[read_line_without_trim]: catch string eq checks

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This commit is contained in:
y21 2023-07-10 19:21:03 +02:00
parent b09fb8ab3b
commit cfddd91c91
1 changed files with 62 additions and 31 deletions
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93
clippy_lints/src/methods/read_line_without_trim.rs
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@ -5,9 +5,10 @@ use clippy_utils::source::snippet;
use clippy_utils::ty::is_type_diagnostic_item;
use clippy_utils::visitors::for_each_local_use_after_expr;
use clippy_utils::{get_parent_expr, match_def_path};
use rustc_ast::LitKind;
use rustc_errors::Applicability;
use rustc_hir::def::Res;
use rustc_hir::{Expr, ExprKind, QPath};
use rustc_hir::{BinOpKind, Expr, ExprKind, QPath};
use rustc_lint::LateContext;
use rustc_middle::ty::{self, Ty};
use rustc_span::sym;
@ -30,37 +31,67 @@ pub fn check(cx: &LateContext<'_>, call: &Expr<'_>, recv: &Expr<'_>, arg: &Expr<
// now let's check if the first use of the string passed to `::read_line()` is
// parsed into a type that will always fail if it has a trailing newline.
for_each_local_use_after_expr(cx, local_id, call.hir_id, |expr| {
if let Some(parent) = get_parent_expr(cx, expr)
&& let ExprKind::MethodCall(segment, .., span) = parent.kind
&& segment.ident.name == sym!(parse)
&& let parse_result_ty = cx.typeck_results().expr_ty(parent)
&& is_type_diagnostic_item(cx, parse_result_ty, sym::Result)
&& let ty::Adt(_, args) = parse_result_ty.kind()
&& let Some(ok_ty) = args[0].as_type()
&& parse_fails_on_trailing_newline(ok_ty)
{
let local_snippet = snippet(cx, expr.span, "<expr>");
span_lint_and_then(
cx,
READ_LINE_WITHOUT_TRIM,
span,
"calling `.parse()` without trimming the trailing newline character",
|diag| {
diag.span_note(
call.span,
"call to `.read_line()` here, \
which leaves a trailing newline character in the buffer, \
which in turn will cause `.parse()` to fail",
);
if let Some(parent) = get_parent_expr(cx, expr) {
if let ExprKind::MethodCall(segment, .., span) = parent.kind
&& segment.ident.name == sym!(parse)
&& let parse_result_ty = cx.typeck_results().expr_ty(parent)
&& is_type_diagnostic_item(cx, parse_result_ty, sym::Result)
&& let ty::Adt(_, substs) = parse_result_ty.kind()
&& let Some(ok_ty) = substs[0].as_type()
&& parse_fails_on_trailing_newline(ok_ty)
{
let local_snippet: std::borrow::Cow<'_, str> = snippet(cx, expr.span, "<expr>");
span_lint_and_then(
cx,
READ_LINE_WITHOUT_TRIM,
span,
"calling `.parse()` without trimming the trailing newline character",
|diag| {
diag.span_note(
call.span,
"call to `.read_line()` here, \
which leaves a trailing newline character in the buffer, \
which in turn will cause `.parse()` to fail",
);
diag.span_suggestion(
expr.span,
"try",
format!("{local_snippet}.trim_end()"),
Applicability::MachineApplicable,
);
},
);
diag.span_suggestion(
expr.span,
"try",
format!("{local_snippet}.trim_end()"),
Applicability::MachineApplicable,
);
},
);
} else if let ExprKind::Binary(binop, _, right) = parent.kind
&& let BinOpKind::Eq = binop.node
&& let ExprKind::Lit(lit) = right.kind
&& let LitKind::Str(sym, _) = lit.node
&& !sym.as_str().ends_with('\n')
{
span_lint_and_then(
cx,
READ_LINE_WITHOUT_TRIM,
parent.span,
"comparing a string literal without trimming the trailing newline character",
|diag| {
let local_snippet = snippet(cx, expr.span, "<expr>");
diag.span_note(
call.span,
"call to `.read_line()` here, \
which leaves a trailing newline character in the buffer, \
which in turn will cause the comparison to always fail",
);
diag.span_suggestion(
expr.span,
"try",
format!("{local_snippet}.trim_end()"),
Applicability::MachineApplicable,
);
},
);
}
}
// only consider the first use to prevent this scenario: