71 lines
3.0 KiB
Swift
71 lines
3.0 KiB
Swift
import SwiftSyntax
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struct FirstWhereRule: SwiftSyntaxRule, OptInRule, ConfigurationProviderRule {
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var configuration = SeverityConfiguration(.warning)
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init() {}
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static let description = RuleDescription(
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identifier: "first_where",
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name: "First Where",
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description: "Prefer using `.first(where:)` over `.filter { }.first` in collections",
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kind: .performance,
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nonTriggeringExamples: [
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Example("kinds.filter(excludingKinds.contains).isEmpty && kinds.first == .identifier\n"),
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Example("myList.first(where: { $0 % 2 == 0 })\n"),
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Example("match(pattern: pattern).filter { $0.first == .identifier }\n"),
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Example("(myList.filter { $0 == 1 }.suffix(2)).first\n"),
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Example(#"collection.filter("stringCol = '3'").first"#),
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Example(#"realm?.objects(User.self).filter(NSPredicate(format: "email ==[c] %@", email)).first"#),
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Example(#"if let pause = timeTracker.pauses.filter("beginDate < %@", beginDate).first { print(pause) }"#)
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],
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triggeringExamples: [
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Example("↓myList.filter { $0 % 2 == 0 }.first\n"),
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Example("↓myList.filter({ $0 % 2 == 0 }).first\n"),
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Example("↓myList.map { $0 + 1 }.filter({ $0 % 2 == 0 }).first\n"),
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Example("↓myList.map { $0 + 1 }.filter({ $0 % 2 == 0 }).first?.something()\n"),
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Example("↓myList.filter(someFunction).first\n"),
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Example("↓myList.filter({ $0 % 2 == 0 })\n.first\n"),
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Example("(↓myList.filter { $0 == 1 }).first\n"),
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Example(#"↓myListOfDict.filter { dict in dict["1"] }.first"#),
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Example(#"↓myListOfDict.filter { $0["someString"] }.first"#)
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]
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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 FirstWhereRule {
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final class Visitor: ViolationsSyntaxVisitor {
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override func visitPost(_ node: MemberAccessExprSyntax) {
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guard
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node.name.text == "first",
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let functionCall = node.base?.asFunctionCall,
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let calledExpression = functionCall.calledExpression.as(MemberAccessExprSyntax.self),
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calledExpression.name.text == "filter",
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!functionCall.argumentList.contains(where: \.expression.shouldSkip)
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else {
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return
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}
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violations.append(functionCall.positionAfterSkippingLeadingTrivia)
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}
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}
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}
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private extension ExprSyntax {
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var shouldSkip: Bool {
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if self.is(StringLiteralExprSyntax.self) {
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return true
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} else if let functionCall = self.as(FunctionCallExprSyntax.self),
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let calledExpression = functionCall.calledExpression.as(IdentifierExprSyntax.self),
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calledExpression.identifier.text == "NSPredicate" {
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return true
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} else {
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return false
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}
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}
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}
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