94 lines
3.9 KiB
Swift
94 lines
3.9 KiB
Swift
import Foundation
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import SourceKittenFramework
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public struct UnusedOptionalBindingRule: ASTRule, ConfigurationProviderRule {
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public var configuration = UnusedOptionalBindingConfiguration(ignoreOptionalTry: false)
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public init() {}
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public static let description = RuleDescription(
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identifier: "unused_optional_binding",
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name: "Unused Optional Binding",
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description: "Prefer `!= nil` over `let _ =`",
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kind: .style,
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nonTriggeringExamples: [
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Example("if let bar = Foo.optionalValue {\n" +
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"}\n"),
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Example("if let (_, second) = getOptionalTuple() {\n" +
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"}\n"),
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Example("if let (_, asd, _) = getOptionalTuple(), let bar = Foo.optionalValue {\n" +
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"}\n"),
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Example("if foo() { let _ = bar() }\n"),
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Example("if foo() { _ = bar() }\n"),
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Example("if case .some(_) = self {}"),
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Example("if let point = state.find({ _ in true }) {}")
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],
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triggeringExamples: [
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Example("if let ↓_ = Foo.optionalValue {\n" +
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"}\n"),
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Example("if let a = Foo.optionalValue, let ↓_ = Foo.optionalValue2 {\n" +
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"}\n"),
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Example("guard let a = Foo.optionalValue, let ↓_ = Foo.optionalValue2 {\n" +
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"}\n"),
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Example("if let (first, second) = getOptionalTuple(), let ↓_ = Foo.optionalValue {\n" +
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"}\n"),
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Example("if let (first, _) = getOptionalTuple(), let ↓_ = Foo.optionalValue {\n" +
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"}\n"),
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Example("if let (_, second) = getOptionalTuple(), let ↓_ = Foo.optionalValue {\n" +
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"}\n"),
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Example("if let ↓(_, _, _) = getOptionalTuple(), let bar = Foo.optionalValue {\n" +
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"}\n"),
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Example("func foo() {\nif let ↓_ = bar {\n}\n"),
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Example("if case .some(let ↓_) = self {}")
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]
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)
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public func validate(file: SwiftLintFile,
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kind: StatementKind,
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dictionary: SourceKittenDictionary) -> [StyleViolation] {
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let conditionKind = "source.lang.swift.structure.elem.condition_expr"
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guard kind == .if || kind == .guard else {
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return []
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}
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let elements = dictionary.elements.filter { $0.kind == conditionKind }
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return elements.flatMap { element -> [StyleViolation] in
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guard let byteRange = element.byteRange,
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let range = file.stringView.byteRangeToNSRange(byteRange)
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else {
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return []
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}
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return violations(in: range, of: file, with: kind).map {
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StyleViolation(ruleDescription: type(of: self).description,
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severity: configuration.severityConfiguration.severity,
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location: Location(file: file, characterOffset: $0.location))
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}
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}
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}
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private func violations(in range: NSRange, of file: SwiftLintFile, with kind: StatementKind) -> [NSRange] {
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let kinds = SyntaxKind.commentAndStringKinds
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let underscorePattern = "(_\\s*[=,)]\\s*(try\\?)?)"
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let underscoreTuplePattern = "(\\((\\s*[_,]\\s*)+\\)\\s*=\\s*(try\\?)?)"
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let letUnderscore = "let\\s+(\(underscorePattern)|\(underscoreTuplePattern))"
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let matches = file.matchesAndSyntaxKinds(matching: letUnderscore, range: range)
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return matches
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.filter { kinds.isDisjoint(with: $0.1) }
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.filter { kind != .guard || !containsOptionalTry(at: $0.0.range, of: file) }
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.map { $0.0.range(at: 1) }
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}
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private func containsOptionalTry(at range: NSRange, of file: SwiftLintFile) -> Bool {
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guard configuration.ignoreOptionalTry else {
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return false
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}
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let matches = file.match(pattern: "try?", with: [.keyword], range: range)
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return !matches.isEmpty
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}
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}
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