|
| 1 | +use biome_analyze::{ |
| 2 | + Rule, RuleDiagnostic, RuleDomain, RuleSource, context::RuleContext, declare_lint_rule, |
| 3 | +}; |
| 4 | +use biome_console::markup; |
| 5 | +use biome_js_syntax::{ |
| 6 | + AnyJsExpression, JsConditionalExpression, JsLogicalExpression, JsLogicalOperator, JsSyntaxNode, |
| 7 | + JsxExpressionAttributeValue, JsxExpressionChild, JsxTagExpression, |
| 8 | + binding_ext::AnyJsBindingDeclaration, |
| 9 | +}; |
| 10 | +use biome_rowan::{AstNode, declare_node_union}; |
| 11 | +use biome_rule_options::no_leaked_render::NoLeakedRenderOptions; |
| 12 | + |
| 13 | +use crate::services::semantic::Semantic; |
| 14 | + |
| 15 | +declare_lint_rule! { |
| 16 | + /// Prevent problematic leaked values from being rendered. |
| 17 | + /// |
| 18 | + /// This rule prevents values that might cause unintentionally rendered values |
| 19 | + /// or rendering crashes in React JSX. When using conditional rendering with the |
| 20 | + /// logical AND operator (`&&`), if the left-hand side evaluates to a falsy value like |
| 21 | + /// `0`, `NaN`, or any empty string, these values will be rendered instead of rendering nothing. |
| 22 | + /// |
| 23 | + /// |
| 24 | + /// ## Examples |
| 25 | + /// |
| 26 | + /// ### Invalid |
| 27 | + /// |
| 28 | + /// ```jsx,expect_diagnostic |
| 29 | + /// const Component = () => { |
| 30 | + /// const count = 0; |
| 31 | + /// return <div>{count && <span>Count: {count}</span>}</div>; |
| 32 | + /// } |
| 33 | + /// ``` |
| 34 | + /// |
| 35 | + /// ```jsx,expect_diagnostic |
| 36 | + /// const Component = () => { |
| 37 | + /// const items = []; |
| 38 | + /// return <div>{items.length && <List items={items} />}</div>; |
| 39 | + /// } |
| 40 | + /// ``` |
| 41 | + /// |
| 42 | + /// ```jsx,expect_diagnostic |
| 43 | + /// const Component = () => { |
| 44 | + /// const user = null; |
| 45 | + /// return <div>{user && <Profile user={user} />}</div>; |
| 46 | + /// } |
| 47 | + /// ``` |
| 48 | + /// |
| 49 | + /// |
| 50 | + /// ### Valid |
| 51 | + /// |
| 52 | + /// ```jsx |
| 53 | + /// const Component = () => { |
| 54 | + /// const count = 0; |
| 55 | + /// return <div>{count > 0 && <span>Count: {count}</span>}</div>; |
| 56 | + /// } |
| 57 | + /// ``` |
| 58 | + /// |
| 59 | + /// ```jsx |
| 60 | + /// const Component = () => { |
| 61 | + /// const items = []; |
| 62 | + /// return <div>{!!items.length && <List items={items} />}</div>; |
| 63 | + /// } |
| 64 | + /// ``` |
| 65 | + /// |
| 66 | + /// ```jsx |
| 67 | + /// const Component = () => { |
| 68 | + /// const user = null; |
| 69 | + /// return <div>{user ? <Profile user={user} /> : null}</div>; |
| 70 | + /// } |
| 71 | + /// ``` |
| 72 | + /// |
| 73 | + /// ```jsx |
| 74 | + /// const Component = () => { |
| 75 | + /// const condition = false; |
| 76 | + /// return <div>{condition ? <Content /> : <Fallback />}</div>; |
| 77 | + /// } |
| 78 | + /// ``` |
| 79 | + /// |
| 80 | + /// ```jsx |
| 81 | + /// const Component = () => { |
| 82 | + /// const isReady = true; |
| 83 | + /// return <div>{isReady && <Content />}</div>; |
| 84 | + /// } |
| 85 | + /// ``` |
| 86 | +
|
| 87 | + pub NoLeakedRender{ |
| 88 | + version: "next", |
| 89 | + name: "noLeakedRender", |
| 90 | + language: "jsx", |
| 91 | + domains: &[RuleDomain::React], |
| 92 | + sources: &[ |
| 93 | + RuleSource::EslintReact("no-leaked-render").inspired(), |
| 94 | + ], |
| 95 | + recommended: false, |
| 96 | + } |
| 97 | +} |
| 98 | + |
| 99 | +impl Rule for NoLeakedRender { |
| 100 | + type Query = Semantic<NoLeakedRenderQuery>; |
| 101 | + type State = bool; |
| 102 | + type Signals = Option<Self::State>; |
| 103 | + type Options = NoLeakedRenderOptions; |
| 104 | + |
| 105 | + fn run(ctx: &RuleContext<Self>) -> Self::Signals { |
| 106 | + let query = ctx.query(); |
| 107 | + let model = ctx.model(); |
| 108 | + |
| 109 | + if !is_inside_jsx_expression(query.syntax()) { |
| 110 | + return None; |
| 111 | + } |
| 112 | + |
| 113 | + match query { |
| 114 | + NoLeakedRenderQuery::JsLogicalExpression(exp) => { |
| 115 | + let op = exp.operator().ok()?; |
| 116 | + |
| 117 | + if op != JsLogicalOperator::LogicalAnd { |
| 118 | + return None; |
| 119 | + } |
| 120 | + let left = exp.left().ok()?; |
| 121 | + |
| 122 | + let is_left_hand_side_safe = matches!( |
| 123 | + left, |
| 124 | + AnyJsExpression::JsUnaryExpression(_) |
| 125 | + | AnyJsExpression::JsCallExpression(_) |
| 126 | + | AnyJsExpression::JsBinaryExpression(_) |
| 127 | + ); |
| 128 | + |
| 129 | + if is_left_hand_side_safe { |
| 130 | + return None; |
| 131 | + } |
| 132 | + |
| 133 | + let mut is_nested_left_hand_side_safe = false; |
| 134 | + |
| 135 | + let mut stack = vec![left.clone()]; |
| 136 | + |
| 137 | + // Traverse the expression tree iteratively using a stack |
| 138 | + // This allows us to check nested expressions without recursion |
| 139 | + while let Some(current) = stack.pop() { |
| 140 | + match current { |
| 141 | + AnyJsExpression::JsLogicalExpression(expr) => { |
| 142 | + let left = expr.left().ok()?.omit_parentheses(); |
| 143 | + let right = expr.right().ok()?.omit_parentheses(); |
| 144 | + stack.push(left); |
| 145 | + stack.push(right); |
| 146 | + } |
| 147 | + AnyJsExpression::JsParenthesizedExpression(expr) => { |
| 148 | + stack.push(expr.expression().ok()?.omit_parentheses()); |
| 149 | + } |
| 150 | + // If we find expressions that coerce to boolean (unary, call, binary), |
| 151 | + // then the entire expression is considered safe |
| 152 | + AnyJsExpression::JsUnaryExpression(_) |
| 153 | + | AnyJsExpression::JsCallExpression(_) |
| 154 | + | AnyJsExpression::JsBinaryExpression(_) => { |
| 155 | + is_nested_left_hand_side_safe = true; |
| 156 | + break; |
| 157 | + } |
| 158 | + _ => {} |
| 159 | + } |
| 160 | + } |
| 161 | + |
| 162 | + if is_nested_left_hand_side_safe { |
| 163 | + return None; |
| 164 | + } |
| 165 | + |
| 166 | + if let AnyJsExpression::JsIdentifierExpression(ident) = &left { |
| 167 | + let name = ident.name().ok()?; |
| 168 | + |
| 169 | + // Use the semantic model to resolve the variable binding and check |
| 170 | + // if it's initialized with a boolean literal. This allows us to |
| 171 | + // handle cases like: |
| 172 | + // let isOpen = false; // This is safe |
| 173 | + // return <div>{isOpen && <Content />}</div>; // This should pass |
| 174 | + if let Some(binding) = model.binding(&name) |
| 175 | + && binding |
| 176 | + .tree() |
| 177 | + .declaration() |
| 178 | + .and_then(|declaration| { |
| 179 | + if let AnyJsBindingDeclaration::JsVariableDeclarator(declarator) = |
| 180 | + declaration |
| 181 | + { |
| 182 | + Some(declarator) |
| 183 | + } else { |
| 184 | + None |
| 185 | + } |
| 186 | + }) |
| 187 | + .and_then(|declarator| declarator.initializer()) |
| 188 | + .and_then(|initializer| initializer.expression().ok()) |
| 189 | + .and_then(|expr| { |
| 190 | + if let AnyJsExpression::AnyJsLiteralExpression(literal) = expr { |
| 191 | + Some(literal) |
| 192 | + } else { |
| 193 | + None |
| 194 | + } |
| 195 | + }) |
| 196 | + .and_then(|literal| literal.value_token().ok()) |
| 197 | + .is_some_and(|token| matches!(token.text_trimmed(), "true" | "false")) |
| 198 | + { |
| 199 | + return None; |
| 200 | + } |
| 201 | + } |
| 202 | + |
| 203 | + let is_literal = matches!(left, AnyJsExpression::AnyJsLiteralExpression(_)); |
| 204 | + if is_literal && left.to_trimmed_text().is_empty() { |
| 205 | + return None; |
| 206 | + } |
| 207 | + |
| 208 | + Some(true) |
| 209 | + } |
| 210 | + NoLeakedRenderQuery::JsConditionalExpression(expr) => { |
| 211 | + let alternate = expr.alternate().ok()?; |
| 212 | + let is_alternate_identifier = |
| 213 | + matches!(alternate, AnyJsExpression::JsIdentifierExpression(_)); |
| 214 | + let is_jsx_element_alt = matches!(alternate, AnyJsExpression::JsxTagExpression(_)); |
| 215 | + if !is_alternate_identifier || is_jsx_element_alt { |
| 216 | + return None; |
| 217 | + } |
| 218 | + |
| 219 | + Some(true) |
| 220 | + } |
| 221 | + } |
| 222 | + } |
| 223 | + |
| 224 | + fn diagnostic(ctx: &RuleContext<Self>, _state: &Self::State) -> Option<RuleDiagnostic> { |
| 225 | + let node = ctx.query(); |
| 226 | + |
| 227 | + match node { |
| 228 | + NoLeakedRenderQuery::JsLogicalExpression(_) => { |
| 229 | + Some( |
| 230 | + RuleDiagnostic::new( |
| 231 | + rule_category!(), |
| 232 | + node.range(), |
| 233 | + markup! { |
| 234 | + "Potential leaked value that might cause unintended rendering." |
| 235 | + }, |
| 236 | + ) |
| 237 | + .note(markup! { |
| 238 | + "JavaScript's && operator returns the left value when it's falsy (e.g., 0, NaN, ''). React will render that value, causing unexpected UI output." |
| 239 | + }) |
| 240 | + .note(markup! { |
| 241 | + "Make sure the condition is explicitly boolean.Use !!value, value > 0, or a ternary expression." |
| 242 | + }) |
| 243 | + ) |
| 244 | + } |
| 245 | + NoLeakedRenderQuery::JsConditionalExpression(_) => { |
| 246 | + Some( |
| 247 | + RuleDiagnostic::new( |
| 248 | + rule_category!(), |
| 249 | + node.range(), |
| 250 | + markup! { |
| 251 | + "Potential leaked value that might cause unintended rendering." |
| 252 | + }, |
| 253 | + ) |
| 254 | + .note(markup! { |
| 255 | + "This happens when you use ternary operators in JSX with alternate values that could be variables." |
| 256 | + }) |
| 257 | + .note(markup! { |
| 258 | + "Replace with a safe alternate value like an empty string , null or another JSX element." |
| 259 | + }) |
| 260 | + ) |
| 261 | + } |
| 262 | + } |
| 263 | + } |
| 264 | +} |
| 265 | + |
| 266 | +declare_node_union! { |
| 267 | + pub NoLeakedRenderQuery = JsLogicalExpression | JsConditionalExpression |
| 268 | +} |
| 269 | + |
| 270 | +fn is_inside_jsx_expression(node: &JsSyntaxNode) -> bool { |
| 271 | + node.ancestors().any(|ancestor| { |
| 272 | + JsxExpressionChild::can_cast(ancestor.kind()) |
| 273 | + || JsxExpressionAttributeValue::can_cast(ancestor.kind()) |
| 274 | + || JsxTagExpression::can_cast(ancestor.kind()) |
| 275 | + }) |
| 276 | +} |
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