swiftlang/swift

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

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#53,798 创建于 2019年8月30日

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 (5 评论) (0 反应) (1 负责人)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.)

贡献者指南

技术栈
swift
领域
backend
议题类型
bug
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
3
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
1-3 hours
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
stale
清晰度议题是否清楚说明期望改动、验收标准和下一步。
clear
前置要求
SwiftgenericsFixedWidthInteger protocolradix conversion
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
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.