Add opt-in unneeded_throws_rethrows rule
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Source/SwiftLintBuiltInRules/Rules/Lint/UnneededThrowsRule.swift
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msrutek-paylocity
approved these changes
May 6, 2025
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@SimplyDanny Any thoughts on this? :) |
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@tonyskansf It seems that some conflicts have arisen, would you mind resolving them? Thanks! |
SimplyDanny
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Jun 30, 2025
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Looks very good already! You thought about many special cases already. The rule also makes sense. But adding it as opt-in is important as it can cause false positives in the context of protocol implementations (and maybe more occasions).
I've added a few comments. Please also check the findings reported by the OSS scan.
Source/SwiftLintBuiltInRules/Rules/Lint/UnneededThrowsRule.swift
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Source/SwiftLintBuiltInRules/Rules/Lint/UnneededThrowsRule.swift
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Source/SwiftLintBuiltInRules/Rules/Lint/UnneededThrowsRule.swift
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Source/SwiftLintBuiltInRules/Rules/Lint/UnneededThrowsRule.swift
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Source/SwiftLintBuiltInRules/Rules/Lint/UnneededThrowsRuleExamples.swift
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Source/SwiftLintBuiltInRules/Rules/Lint/UnneededThrowsRule.swift
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| var children = Set(typeAnnotation.children(viewMode: .sourceAccurate)) | ||
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| while let child = children.popFirst() { |
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That's dangerous. Consider this example:
let s: S<() throws -> Void> = S()I think, you should be explicit about the syntax structure to match instead of iterating through all children.
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I see that for you example it is incorrectly triggering.
be explicit about the syntax structure to match instead of iterating through all children
I'll try to come up with a better solution for these cases
let s: S<() throws -> Void> = S()let foo: () ↓throws -> Void = {}
Thanks for pointing this out
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Please check out 25c4905.
Instead of iterating over all children, this implementation checks the PatternBindingSyntax.typeAnnotation type for only specific cases - that should be more explicit about which syntax structure we're interested in.
Please let me know if this is better approach or suggest other.
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Looks better. TupleTypeSyntax is only relevant when the tuple has only one element, isn't it. Otherwise, it's hard to check the necessity of throws keywords.
Also, we should have test case for the cases in the switch of the types.
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That's true. The necessity of throws keywords could depend on a context we don't know.
I'll keep the check for single-element TupleTypeSyntax only. Making the rule less strict.
I've also added new test cases.
Source/SwiftLintBuiltInRules/Rules/Lint/UnneededThrowsRule.swift
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You need to rebase onto |
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SimplyDanny
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Source/SwiftLintBuiltInRules/Rules/Lint/UnneededThrowsRule.swift
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Source/SwiftLintBuiltInRules/Rules/Lint/UnneededThrowsRule.swift
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| var children = Set(typeAnnotation.children(viewMode: .sourceAccurate)) | ||
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| while let child = children.popFirst() { |
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Looks better. TupleTypeSyntax is only relevant when the tuple has only one element, isn't it. Otherwise, it's hard to check the necessity of throws keywords.
Also, we should have test case for the cases in the switch of the types.
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@SimplyDanny Please can you take a look again. Appreciate your time! Thank you |
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Add a new opt-in rule that detects unnecessary
throws, helping avoid misleading definitions and requirements for the caller to write unnecessary error handling.