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feat(linter): implement configuration and checking loops for eslint/no_constant_condition #10949

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Merged
camc314 merged 4 commits into from
May 13, 2025
Merged

feat(linter): implement configuration and checking loops for eslint/no_constant_condition #10949

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47af887
check loops and implement configuration correctly
ulrichstark May 11, 2025
081a3f0
reduce diff
ulrichstark May 12, 2025
be56e36
simplify check
ulrichstark May 12, 2025
9232262
update rule docs
ulrichstark May 12, 2025
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217 changes: 149 additions & 68 deletions crates/oxc_linter/src/rules/eslint/no_constant_condition.rs
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Original file line number Diff line number Diff line change
@@ -1,7 +1,8 @@
use oxc_ast::AstKind;
use oxc_ast::{AstKind, ast::Expression};
use oxc_diagnostics::OxcDiagnostic;
use oxc_macros::declare_oxc_lint;
use oxc_span::{GetSpan, Span};
use serde_json::Value;

use crate::{AstNode, ast_util::IsConstant, context::LintContext, rule::Rule};

Expand All @@ -11,9 +12,38 @@ fn no_constant_condition_diagnostic(span: Span) -> OxcDiagnostic {
.with_label(span)
}

#[derive(Debug, Default, Clone, PartialEq)]
enum CheckLoops {
All,
#[default]
AllExceptWhileTrue,
None,
}

impl CheckLoops {
fn from(value: &Value) -> Option<Self> {
match value {
Value::String(str) => match str.as_str() {
"all" => Some(Self::All),
"allExceptWhileTrue" => Some(Self::AllExceptWhileTrue),
"none" => Some(Self::None),
_ => None,
},
Value::Bool(bool) => {
if *bool {
Some(Self::All)
} else {
Some(Self::None)
}
}
_ => None,
}
}
}

#[derive(Debug, Default, Clone)]
pub struct NoConstantCondition {
_check_loops: bool,
check_loops: CheckLoops,
}

declare_oxc_lint!(
Expand All @@ -31,73 +61,108 @@ declare_oxc_lint!(
/// - `if`, `for`, `while`, or `do...while` statement
/// - `?`: ternary expression
///
///
/// ### Example
/// ### Examples
///
/// Examples of **incorrect** code for this rule:
/// ```js
/// if (false) {
/// doSomethingUnfinished();
/// doSomethingUnfinished();
/// }
///
/// if (new Boolean(x)) {
/// doSomethingAlways();
/// doSomethingAlways();
/// }
/// if (x ||= true) {
/// doSomethingAlways();
/// doSomethingAlways();
/// }
///
/// do {
/// doSomethingForever();
/// doSomethingForever();
/// } while (x = -1);
/// ```
///
/// Examples of **correct** code for this rule:
/// ```js
/// if (x === 0) {
/// doSomething();
/// doSomething();
/// }
///
/// while (typeof x === "undefined") {
/// doSomething();
/// doSomething();
/// }
/// ```
///
/// ### Options
///
/// #### checkLoops
///
/// `{ type: "all" | "allExceptWhileTrue" | "none" | boolean, default: "allExceptWhileTrue" }`
///
/// - `"all"` or `true` disallows constant expressions in loops
/// - `"allExceptWhileTrue"` disallows constant expressions in loops except while loops with expression `true`
/// - `"none"` or `false` allows constant expressions in loops
NoConstantCondition,
eslint,
correctness
);

impl Rule for NoConstantCondition {
fn from_configuration(value: serde_json::Value) -> Self {
fn from_configuration(value: Value) -> Self {
let obj = value.get(0);

Self {
_check_loops: obj
check_loops: obj
.and_then(|v| v.get("checkLoops"))
.and_then(serde_json::Value::as_bool)
.and_then(CheckLoops::from)
.unwrap_or_default(),
}
}

fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
match node.kind() {
AstKind::IfStatement(if_stmt) => {
if if_stmt.test.is_constant(true, ctx) {
ctx.diagnostic(no_constant_condition_diagnostic(if_stmt.test.span()));
}
AstKind::IfStatement(if_stmt) => check(ctx, &if_stmt.test),
AstKind::ConditionalExpression(condition_expr) => check(ctx, &condition_expr.test),
AstKind::WhileStatement(while_stmt) => self.check_loop(ctx, &while_stmt.test, true),
AstKind::DoWhileStatement(do_while_stmt) => {
self.check_loop(ctx, &do_while_stmt.test, false);
}
AstKind::ConditionalExpression(condition_expr) => {
if condition_expr.test.is_constant(true, ctx) {
ctx.diagnostic(no_constant_condition_diagnostic(condition_expr.test.span()));
}
AstKind::ForStatement(for_stmt) => {
let Some(test) = &for_stmt.test else {
return;
};

self.check_loop(ctx, test, false);
}
_ => {}
}
}
}

impl NoConstantCondition {
fn check_loop<'a>(&self, ctx: &LintContext<'a>, test: &'a Expression<'_>, is_while: bool) {
match self.check_loops {
CheckLoops::None => return,
CheckLoops::AllExceptWhileTrue if is_while => match test {
Expression::BooleanLiteral(bool) if bool.value => return,
_ => {}
},
_ => {}
}

check(ctx, test);
}
}

fn check<'a>(ctx: &LintContext<'a>, test: &'a Expression<'_>) {
if test.is_constant(true, ctx) {
ctx.diagnostic(no_constant_condition_diagnostic(test.span()));
}
}

#[test]
fn test() {
use serde_json::json;

use crate::tester::Tester;

let pass = vec![
Expand Down Expand Up @@ -220,28 +285,36 @@ fn test() {
// ("const undefined = 'lol'; if (undefined) {}", None),
// ("function foo(Boolean) { if (Boolean(1)) {} }", None),
// ("const Boolean = () => {}; if (Boolean(1)) {}", None),
// "if (Boolean()) {}",
// "if (undefined) {}",
// ("if (Boolean()) {}", None),
// ("if (undefined) {}", None),
("q > 0 ? 1 : 2;", None),
("`${a}` === a ? 1 : 2", None),
("`foo${a}` === a ? 1 : 2", None),
("tag`a` === a ? 1 : 2", None),
("tag`${a}` === a ? 1 : 2", None),
//TODO
// ("while(~!a);", None),
// ("while(a = b);", None),
// ("while(`${a}`);", None),
// ("for(;x < 10;);", None),
// ("for(;;);", None),
// ("for(;`${a}`;);", None),
// ("do{ }while(x)", None),
// ("while(x += 3) {}", None),
// ("while(tag`a`) {}", None),
// ("while(tag`${a}`) {}", None),
// ("while(`\\\n${a}`) {}", None),
// ("while(true);", Some(json!([{"checkLoops":false}]))),
// ("for(;true;);", Some(json!([{"checkLoops":false}]))),
// ("do{}while(true)", Some(json!([{"checkLoops":false}]))),
("while(~!a);", None),
("while(a = b);", None),
("while(`${a}`);", None),
("for(;x < 10;);", None),
("for(;;);", None),
("for(;`${a}`;);", None),
("do{ }while(x)", None),
("while(x += 3) {}", None),
("while(tag`a`) {}", None),
("while(tag`${a}`) {}", None),
("while(`\\\n${a}`) {}", None),
("while(true);", Some(json!([{ "checkLoops": false }]))),
("for(;true;);", Some(json!([{ "checkLoops": false }]))),
("do{}while(true)", Some(json!([{ "checkLoops": "none" }]))),
("while(true);", Some(json!([{ "checkLoops": "none" }]))),
("for(;true;);", Some(json!([{ "checkLoops": "none" }]))),
("do{ }while(x);", Some(json!([{ "checkLoops": "all" }]))),
("while(true);", Some(json!([{ "checkLoops": "allExceptWhileTrue" }]))),
("while(true);", None),
("while(a == b);", Some(json!([{ "checkLoops": "all" }]))),
("for (let x = 0; x <= 10; x++) {};", Some(json!([{ "checkLoops": "all" }]))),
("do{}while(true)", Some(json!([{ "checkLoops": false }]))),
// TODO
// ("function* foo(){while(true){yield 'foo';}}", None),
// ("function* foo(){for(;true;){yield 'foo';}}", None),
// ("function* foo(){do{yield 'foo';}while(true)}", None),
Expand All @@ -254,7 +327,6 @@ fn test() {
];

let fail = vec![
("if(-2);", None),
("if(-2);", None),
("if(true);", None),
("if(1);", None),
Expand Down Expand Up @@ -306,11 +378,13 @@ fn test() {
("if((a &&= null) && b);", None),
("if(false || (a &&= false));", None),
("if((a &&= false) || false);", None),
("while(x = 1);", None),
("if(typeof x){}", None),
("if(typeof 'abc' === 'string'){}", None),
("if(a = typeof b){}", None),
("if(a, typeof b){}", None),
("if(typeof 'a' == 'string' || typeof 'b' == 'string'){}", None),
("while(typeof x){}", None),
("if(1 || void x);", None),
("if(void x);", None),
("if(y = void x);", None),
Expand Down Expand Up @@ -370,39 +444,46 @@ fn test() {
("`` ? 1 : 2;", None),
("`foo` ? 1 : 2;", None),
("`foo${bar}` ? 1 : 2;", None),
("for(;true;);", None),
("for(;``;);", None),
("for(;`foo`;);", None),
("for(;`foo${bar}`;);", None),
("do{}while(true)", None),
("do{}while('1')", None),
("do{}while(0)", None),
("do{}while(t = -2)", None),
("do{}while(``)", None),
("do{}while(`foo`)", None),
("do{}while(`foo${bar}`)", None),
("while([]);", None),
("while(~!0);", None),
("while(x = 1);", Some(json!([{ "checkLoops": "all" }]))),
("while(function(){});", None),
("while(true);", Some(json!([{ "checkLoops": "all" }]))),
("while(1);", None),
("while(() => {});", None),
("while(`foo`);", None),
("while(``);", None),
("while(`${'foo'}`);", None),
("while(`${'foo' + 'bar'}`);", None),
("do{ }while(x = 1)", Some(json!([{ "checkLoops": "all" }]))),
("for (;true;) {};", Some(json!([{ "checkLoops": "all" }]))),
// TODO
// ("for(;true;);", None),
// ("for(;``;);", None),
// ("for(;`foo`;);", None),
// ("for(;`foo${bar}`;);", None),
// ("do{}while(true)", None),
// ("do{}while('1')", None),
// ("do{}while(0)", None),
// ("do{}while(t = -2)", None),
// ("do{}while(``)", None),
// ("do{}while(`foo`)", None),
// ("do{}while(`foo${bar}`)", None),
// ("while([]);", None),
// ("while(~!0);", None),
// ("while(x = 1);", None),
// ("while(function(){});", None),
// ("while(true);", None),
// ("while(1);", None),
// ("while(() => {});", None),
// ("while(`foo`);", None),
// ("while(``);", None),
// ("while(`${'foo'}`);", None),
// ("while(`${'foo' + 'bar'}`);", None),
// ("function* foo(){while(true){} yield 'foo';}", None),
// ("function* foo(){while(true){if (true) {yield 'foo';}}}", None),
// ("function* foo(){while(true){yield 'foo';} while(true) {}}", None),
// ("var a = function* foo(){while(true){} yield 'foo';}", None),
// ("while (true) { function* foo() {yield;}}", None),
// ("function* foo(){while(true){} yield 'foo';}", Some(json!([{ "checkLoops": "all" }]))),
// ("function* foo(){while(true){} yield 'foo';}", Some(json!([{ "checkLoops": true }]))),
// ("function* foo(){while(true){if (true) {yield 'foo';}}}",Some(json!([{ "checkLoops": "all" }])),),
// ("function* foo(){while(true){if (true) {yield 'foo';}}}",Some(json!([{ "checkLoops": true }])),),
// ("function* foo(){while(true){yield 'foo';} while(true) {}}", Some(json!([{ "checkLoops": "all" }])),),
// ("function* foo(){while(true){yield 'foo';} while(true) {}}",Some(json!([{ "checkLoops": true }])),),
// ("var a = function* foo(){while(true){} yield 'foo';}",Some(json!([{ "checkLoops": "all" }])),),
// ("var a = function* foo(){while(true){} yield 'foo';}",Some(json!([{ "checkLoops": true }])),),
// ("while (true) { function* foo() {yield;}}", Some(json!([{ "checkLoops": "all" }]))),
// ("while (true) { function* foo() {yield;}}", Some(json!([{ "checkLoops": true }]))),
// ("function* foo(){if (true) {yield 'foo';}}", None),
// ("function* foo() {for (let foo = yield; true;) {}}", None),
// ("function* foo() {for (foo = yield; true;) {}}", None),
// ("function foo() {while (true) {function* bar() {while (true) {yield;}}}}", None),
// ("function foo() {while (true) {const bar = function*() {while (true) {yield;}}}}", None),
// ("function foo() {while (true) {function* bar() {while (true) {yield;}}}}",Some(json!([{ "checkLoops": "all" }])),),
// ("function foo() {while (true) {const bar = function*() {while (true) {yield;}}}}",Some(json!([{ "checkLoops": "all" }])),),
// ("function* foo() { for (let foo = 1 + 2 + 3 + (yield); true; baz) {}}", None),
];

Expand Down
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