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swift-mirror/test/stdlib/StringTraps.swift
Michael Ilseman 415cc8fb0c [String.Index] Deprecate encodedOffset var/init
String.Index has an encodedOffset-based initializer and computed
property that exists for serialization purposes. It was documented as
UTF-16 in the SE proposal introducing it, which was String's
underlying encoding at the time, but the dream of String even then was
to abstract away whatever encoding happend to be used.

Serialization needs an explicit encoding for serialized indices to
make sense: the offsets need to align with the view. With String
utilizing UTF-8 encoding for native contents in Swift 5, serialization
isn't necessarily the most efficient in UTF-16.

Furthermore, the majority of usage of encodedOffset in the wild is
buggy and operates under the assumption that a UTF-16 code unit was a
Swift Character, which isn't even valid if the String is known to be
all-ASCII (because CR-LF).

This change introduces a pair of semantics-preserving alternatives to
encodedOffset that explicitly call out the UTF-16 assumption. These
serve as a gentle off-ramp for current mis-uses of encodedOffset.
2019-02-13 18:42:40 -08:00

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// RUN: %empty-directory(%t)
// RUN: %target-build-swift %s -o %t/a.out_Debug -Onone
// RUN: %target-build-swift %s -o %t/a.out_Release -O
//
// RUN: %target-codesign %t/a.out_Debug
// RUN: %target-codesign %t/a.out_Release
// RUN: %target-run %t/a.out_Debug
// RUN: %target-run %t/a.out_Release
// REQUIRES: executable_test
import StdlibUnittest
let testSuiteSuffix = _isDebugAssertConfiguration() ? "_debug" : "_release"
var StringTraps = TestSuite("StringTraps" + testSuiteSuffix)
StringTraps.test("startIndex/predecessor")
.skip(.custom(
{ _isFastAssertConfiguration() },
reason: "this trap is not guaranteed to happen in -Ounchecked"))
.code {
let s = "abc"
var i = s.startIndex
i = s.index(after: i)
i = s.index(before: i)
expectCrashLater()
i = s.index(before: i)
}
StringTraps.test("endIndex/successor")
.skip(.custom(
{ _isFastAssertConfiguration() },
reason: "this trap is not guaranteed to happen in -Ounchecked"))
.code {
let s = "abc"
var i = s.startIndex
i = s.index(after: i)
i = s.index(after: i)
i = s.index(after: i)
expectCrashLater()
i = s.index(after: i)
}
StringTraps.test("subscript(_:)/endIndex")
.skip(.custom(
{ _isFastAssertConfiguration() },
reason: "this trap is not guaranteed to happen in -Ounchecked"))
.code {
let s = "abc"
var i = s.startIndex
i = s.index(after: i)
i = s.index(after: i)
i = s.index(after: i)
expectCrashLater()
_ = s[i]
}
StringTraps.test("UTF8ViewSubscript/endIndexSuccessor")
.skip(.custom(
{ _isFastAssertConfiguration() },
reason: "this trap is not guaranteed to happen in -Ounchecked"))
.code {
let s = "abc"
var i = s.utf8.startIndex
i = s.utf8.index(after: i)
i = s.utf8.index(after: i)
i = s.utf8.index(after: i)
expectCrashLater()
i = s.utf8.index(after: i)
_ = s.utf8[i]
}
StringTraps.test("UTF8ViewSubscript/endIndex")
.skip(.custom(
{ _isFastAssertConfiguration() },
reason: "this trap is not guaranteed to happen in -Ounchecked"))
.code {
let s = "abc"
var i = s.utf8.startIndex
i = s.utf8.index(after: i)
i = s.utf8.index(after: i)
i = s.utf8.index(after: i)
expectCrashLater()
_ = s.utf8[i]
}
StringTraps.test("UTF16ViewSubscript/DecrementedStartIndex")
.skip(.custom(
{ _isFastAssertConfiguration() },
reason: "this trap is not guaranteed to happen in -Ounchecked"))
.code {
let s = "abc"
var i = s.utf16.startIndex
expectCrashLater()
i = s.utf16.index(before: i)
_ = s.utf16[i]
}
StringTraps.test("UTF16ViewSubscript/endIndex")
.skip(.custom(
{ _isFastAssertConfiguration() },
reason: "this trap is not guaranteed to happen in -Ounchecked"))
.code {
var s = "abc"
var i = s.utf16.startIndex
i = s.utf16.index(after: i)
i = s.utf16.index(after: i)
i = s.utf16.index(after: i)
expectCrashLater()
_ = s.utf16[i]
}
StringTraps.test("UTF16ViewIndex/offsetLimited")
.code {
let sa = "foo"
let u16a = sa.utf16
let s16 = sa + "🤦🏻‍♀️"
let u16 = s16.utf16
let iaBegin = u16a.index(sa.startIndex, offsetBy: 99, limitedBy: sa.endIndex)
expectNil(iaBegin)
let iaEnd = u16a.index(sa.endIndex, offsetBy: 99, limitedBy: sa.endIndex)
expectNil(iaEnd)
let i16Begin = u16.index(u16.startIndex, offsetBy: 99, limitedBy: u16.endIndex)
expectNil(i16Begin)
let i16End = u16.index(u16.startIndex, offsetBy: 99, limitedBy: u16.endIndex)
expectNil(i16End)
}
StringTraps.test("UTF16ViewIndex/offsetCrash")
.skip(.custom(
{ _isFastAssertConfiguration() },
reason: "this trap is not guaranteed to happen in -Ounchecked"))
.code {
let s16 = "foo🤦🏻"
let u16 = s16.utf16
expectCrashLater()
let i = u16.index(u16.startIndex, offsetBy: 99)
_ = s16.utf16[i]
}
StringTraps.test("UTF8ViewIndex/offsetLimited")
.code {
let sa = "foo"
let u8a = sa.utf8
let s8 = sa + "🤦🏻‍♀️"
let u8 = s8.utf8
let iaBegin = u8a.index(sa.startIndex, offsetBy: 99, limitedBy: sa.endIndex)
expectNil(iaBegin)
let iaEnd = u8a.index(sa.endIndex, offsetBy: 99, limitedBy: sa.endIndex)
expectNil(iaEnd)
let i8Begin = u8.index(u8.startIndex, offsetBy: 99, limitedBy: u8.endIndex)
expectNil(i8Begin)
let i8End = u8.index(u8.startIndex, offsetBy: 99, limitedBy: u8.endIndex)
expectNil(i8End)
}
StringTraps.test("UTF8ViewIndex/offsetCrash")
.skip(.custom(
{ _isFastAssertConfiguration() },
reason: "this trap is not guaranteed to happen in -Ounchecked"))
.code {
let s8 = "foo🤦🏻"
let u8 = s8.utf8
expectCrashLater()
let i = u8.index(u8.startIndex, offsetBy: 99)
_ = s8.utf8[i]
}
StringTraps.test("String.Index.utf16Offset(in:)/subscalarUTF8")
.skip(.custom(
{ _isFastAssertConfiguration() },
reason: "this trap is not guaranteed to happen in -Ounchecked"))
.code {
let s = "😇"
let u8 = s.utf8
let i = u8.index(after: u8.startIndex)
expectCrashLater()
_ = i.utf16Offset(in: s)
}
runAllTests()