120 lines
3.5 KiB
Swift
120 lines
3.5 KiB
Swift
import SwiftSyntax
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private let warnDeprecatedOnceImpl: Void = {
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queuedPrintError("""
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The `\(InertDeferRule.description.identifier)` rule is now deprecated and will be completely \
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removed in a future release due to an equivalent warning issued by the Swift compiler.
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"""
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)
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}()
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private func warnDeprecatedOnce() {
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_ = warnDeprecatedOnceImpl
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}
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struct InertDeferRule: ConfigurationProviderRule, SwiftSyntaxRule, OptInRule {
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var configuration = SeverityConfiguration(.warning)
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static let description = RuleDescription(
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identifier: "inert_defer",
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name: "Inert Defer",
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description: "If defer is at the end of its parent scope, it will be executed right where it is anyway",
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kind: .lint,
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nonTriggeringExamples: [
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Example("""
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func example3() {
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defer { /* deferred code */ }
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print("other code")
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}
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"""),
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Example("""
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func example4() {
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if condition {
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defer { /* deferred code */ }
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print("other code")
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}
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}
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"""),
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Example("""
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func f() {
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#if os(macOS)
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defer { print(2) }
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#else
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defer { print(3) }
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#endif
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print(1)
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}
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""", excludeFromDocumentation: true)
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],
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triggeringExamples: [
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Example("""
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func example0() {
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↓defer { /* deferred code */ }
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}
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"""),
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Example("""
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func example1() {
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↓defer { /* deferred code */ }
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// comment
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}
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"""),
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Example("""
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func example2() {
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if condition {
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↓defer { /* deferred code */ }
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// comment
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}
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}
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"""),
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Example("""
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func f(arg: Int) {
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if arg == 1 {
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↓defer { print(2) }
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// a comment
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} else {
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↓defer { print(3) }
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}
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print(1)
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#if os(macOS)
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↓defer { print(4) }
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#else
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↓defer { print(5) }
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#endif
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}
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""", excludeFromDocumentation: true)
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]
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)
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func makeVisitor(file: SwiftLintFile) -> ViolationsSyntaxVisitor {
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warnDeprecatedOnce()
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return Visitor(viewMode: .sourceAccurate)
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}
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}
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private extension InertDeferRule {
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final class Visitor: ViolationsSyntaxVisitor {
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override func visitPost(_ node: DeferStmtSyntax) {
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guard node.isLastStatement else {
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return
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}
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if let ifConfigClause = node.parent?.parent?.parent?.as(IfConfigClauseSyntax.self),
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ifConfigClause.parent?.parent?.isLastStatement == false {
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return
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}
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violations.append(node.deferKeyword.positionAfterSkippingLeadingTrivia)
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}
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}
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}
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private extension SyntaxProtocol {
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var isLastStatement: Bool {
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if let codeBlockItem = parent?.as(CodeBlockItemSyntax.self),
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let codeBlockList = codeBlockItem.parent?.as(CodeBlockItemListSyntax.self) {
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return codeBlockList.last == codeBlockItem
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}
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return false
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}
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}
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