85 lines
3.6 KiB
Swift
85 lines
3.6 KiB
Swift
import SwiftSyntax
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struct LegacyMultipleRule: OptInRule, ConfigurationProviderRule, SwiftSyntaxRule {
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var configuration = SeverityConfiguration(.warning)
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static let description = RuleDescription(
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identifier: "legacy_multiple",
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name: "Legacy Multiple",
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description: "Prefer using the `isMultiple(of:)` function instead of using the remainder operator (`%`)",
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kind: .idiomatic,
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nonTriggeringExamples: [
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Example("cell.contentView.backgroundColor = indexPath.row.isMultiple(of: 2) ? .gray : .white"),
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Example("guard count.isMultiple(of: 2) else { throw DecodingError.dataCorrupted(...) }"),
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Example("sanityCheck(bytes > 0 && bytes.isMultiple(of: 4), \"capacity must be multiple of 4 bytes\")"),
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Example("guard let i = reversedNumbers.firstIndex(where: { $0.isMultiple(of: 2) }) else { return }"),
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Example("""
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let constant = 56
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let isMultiple = value.isMultiple(of: constant)
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"""),
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Example("""
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let constant = 56
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let secret = value % constant == 5
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"""),
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Example("let secretValue = (value % 3) + 2")
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],
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triggeringExamples: [
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Example("cell.contentView.backgroundColor = indexPath.row ↓% 2 == 0 ? .gray : .white"),
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Example("cell.contentView.backgroundColor = 0 == indexPath.row ↓% 2 ? .gray : .white"),
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Example("cell.contentView.backgroundColor = indexPath.row ↓% 2 != 0 ? .gray : .white"),
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Example("guard count ↓% 2 == 0 else { throw DecodingError.dataCorrupted(...) }"),
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Example("sanityCheck(bytes > 0 && bytes ↓% 4 == 0, \"capacity must be multiple of 4 bytes\")"),
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Example("guard let i = reversedNumbers.firstIndex(where: { $0 ↓% 2 == 0 }) else { return }"),
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Example("""
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let constant = 56
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let isMultiple = value ↓% constant == 0
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""")
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]
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)
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func preprocess(file: SwiftLintFile) -> SourceFileSyntax? {
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file.foldedSyntaxTree
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}
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func makeVisitor(file: SwiftLintFile) -> ViolationsSyntaxVisitor {
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Visitor(viewMode: .sourceAccurate)
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}
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}
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private extension LegacyMultipleRule {
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final class Visitor: ViolationsSyntaxVisitor {
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override func visitPost(_ node: InfixOperatorExprSyntax) {
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guard let operatorNode = node.operatorOperand.as(BinaryOperatorExprSyntax.self),
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operatorNode.operatorToken.tokenKind == .binaryOperator("%"),
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let parent = node.parent?.as(InfixOperatorExprSyntax.self),
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let parentOperatorNode = parent.operatorOperand.as(BinaryOperatorExprSyntax.self),
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parentOperatorNode.isEqualityOrInequalityOperator else {
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return
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}
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let isExprEqualTo0 = {
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parent.leftOperand.as(InfixOperatorExprSyntax.self) == node &&
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parent.rightOperand.as(IntegerLiteralExprSyntax.self)?.isZero == true
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}
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let is0EqualToExpr = {
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parent.leftOperand.as(IntegerLiteralExprSyntax.self)?.isZero == true &&
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parent.rightOperand.as(InfixOperatorExprSyntax.self) == node
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}
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guard isExprEqualTo0() || is0EqualToExpr() else {
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return
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}
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violations.append(node.operatorOperand.positionAfterSkippingLeadingTrivia)
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}
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}
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}
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private extension BinaryOperatorExprSyntax {
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var isEqualityOrInequalityOperator: Bool {
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operatorToken.tokenKind == .binaryOperator("==") ||
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operatorToken.tokenKind == .binaryOperator("!=")
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}
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}
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