[Lint/Format] Add a rule to omit return from functions, closures, subscripts, and variables
#596
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| let decl = super.visit(node) | ||
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| // func <name>() -> <Type> { return ... } | ||
| if var funcDecl = decl.as(FunctionDeclSyntax.self), |
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Nit: Here and elsewhere, can you make these kinds of conditions guards instead so that the "interesting" part of the function is at the bottom and unnested?
| // func <name>() -> <Type> { return ... } | ||
| if var funcDecl = decl.as(FunctionDeclSyntax.self), | ||
| let body = funcDecl.body, | ||
| let `return` = containsSingleReturn(body.statements) { |
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I think it reads a little better if these variables were named returnStmt, subscriptDecl, instead of escaping just the keyword. `return` is a little ambiguous because it's not clear if it's referring to the statement or the keyword token.
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| diagnose(.omitReturnStatement, on: `return`, severity: .refactoring) | ||
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| return .init( |
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At some point soon I'll be working on a modernization pass of the code base that starts doing regular mutation on nodes. Can you change this to just mutate a copy of the node and return that? For example,
var newBlock = accessorBlock
accessorBlock.accessors = .accessors(accessors.with(\.[getterAt], getter)
return newBlock
Likewise for the other branch below. This makes it easier to scan quickly and see what part of the node is being changed and what parts are staying the same.
| /// Format: `func <name>() { return ... }` constructs will be replaced with | ||
| /// equivalent `func <name>() { ... }` constructs. | ||
| @_spi(Rules) | ||
| public final class OmitReturns: SyntaxFormatRule { |
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Can we use OmitSingleExpressionReturns as the rule name instead, so it's a little more self-descriptive?
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This is more confusing to me, maybe OmitExplicitReturns? Verbose version is OmitExplicitReturnsFromSingleExpressionBodies
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OmitExplicitReturns sounds good to me!
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| extension Finding.Message { | ||
| public static let omitReturnStatement: Finding.Message = | ||
| "`return` can be omitted because body consists of a single expression" |
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| "`return` can be omitted because body consists of a single expression" | |
| "remove 'return' because the body is a single expression" |
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(As a style choice, we use single quotes instead of backticks, since that matched Swift compiler error messages at the time. However, it also looks like diagnostics have been introduced since then that use backticks...)
| return nil | ||
| } | ||
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| private func unwrapReturnStmt(_ `return`: ReturnStmtSyntax) -> CodeBlockItemListSyntax { |
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Maybe rewrapReturnedExpression for the name of this method? It's doing more than just unwrapping it, it's also wrapping it back up in a code block item list.
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Thank you, I'll try to address this today! |
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@allevato I think I addressed all of the style/naming comments, please let me know if I missed something. |
This is an opt-in rule that would warn about a possible refactoring in lint mode and drop returns from single-expression bodies of functions, closures, subscripts and computed variables/properties.