swiftlang/swift

[SR-11397] FixedWidthInteger.init?(_: radix:) fails for Self with short bitWidth

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#53,798 建立於 2019年8月30日

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 (5 留言) (0 反應) (1 負責人)Swift (69,989 star) (10,719 fork)batch import
buggood first issuestandard library

描述
Previous ID SR-11397
Radar None
Original Reporter CTMacUser (JIRA User)
Type Bug
Votes 0
Component/s Standard Library
Labels Bug, StarterBug
Assignee @theblixguy
Priority Medium

md5: 71036ce9352bad83dc05a0cfcdea3df7

Issue Description:

The current implementation of FixedWidthInteger.init?(_: radix: ) converts the radix to the receiver type. If that type has less than 6 bits of width, not all radix values are supported and a run error happens at the conversion.

Theoretically, any width above zero should work if we go to a bignum implementation. I'm not suggesting we do that, but that workaround indicates we shouldn't return a nil from the initializer in such cases, because that would imply a user error and not a implementation error. I guess a fatal error is more appropriate.

(BTW, my code was testing with a zero-width type, so there may be other problems.)

貢獻者指南

技術棧
swift
領域
backend
議題類型
bug
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
3
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
1-3 hours
活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。
stale
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
clear
前置要求
SwiftgenericsFixedWidthInteger protocolradix conversion
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
75
研究方向
Look into the current implementation of FixedWidthInteger.init?( : radix:) in the Swift standard library, likely in IntegerTypes.swift. The issue describes that for types with bit width less than 6, the radix conversion to the receiver type fails. Consider replacing the current behavior with a fatal error for unsupported radices, as suggested. Review comments for any additional context; note the assignee @theblixguy may have existing work.