Crash on emoji as typealias with 0.14.0

[mknabbe]

Swiftlint 0.14.0 crashes when run as build phase in Xcode 8.2 (8C38) while trying to parse following statement:
public typealias 🔳 = QRCode

/Users/XXXXX/Library/Developer/Xcode/DerivedData/XXXXXX-aqobyostblawgtbajeamvisokbcm/Build/Intermediates/CodeCoverage/Intermediates/XXXXXX.build/Debug-appletvsimulator/XXXXXX.build/Script-5BEA03541CCE131F008B1777.sh: line 6: 16251 Illegal instruction: 4 swiftlint
Command /bin/sh failed with exit code 132

[jpsim]

That's a fun one 😄 . Thanks for reporting! Although I can't reproduce this...

$ echo "public typealias 🔳 = QRCode" | swiftlint lint --use-stdin
Done linting! Found 0 violations, 0 serious in 1 file.

What does your configuration look like? Are you enabling any opt-in rules? Are you sure it crashes with just the sample you've provided, or does that string crash with a rule for text later in the file?

[marcelofabri]

I was able to reproduce the crash by adding this example on nonTriggeringExamples and running the tests:

Test Case '-[SwiftLintFrameworkTests.RulesTests testTypeName]' started.
fatal error: unexpectedly found nil while unwrapping an Optional value
2016-12-19 18:51:24.140399 xctest[2255:2159887] fatal error: unexpectedly found nil while unwrapping an Optional value
Current stack trace:
0    libswiftCore.dylib                 0x0000000105c55ce0 swift_reportError + 132
1    libswiftCore.dylib                 0x0000000105c73090 _swift_stdlib_reportFatalError + 61
2    libswiftCore.dylib                 0x0000000105a690c0 specialized specialized StaticString.withUTF8Buffer<A> ((UnsafeBufferPointer<UInt8>) -> A) -> A + 355
3    libswiftCore.dylib                 0x0000000105be5230 partial apply for (_fatalErrorMessage(StaticString, StaticString, StaticString, UInt, flags : UInt32) -> Never).(closure #2) + 109
4    libswiftCore.dylib                 0x0000000105a690c0 specialized specialized StaticString.withUTF8Buffer<A> ((UnsafeBufferPointer<UInt8>) -> A) -> A + 355
5    libswiftCore.dylib                 0x0000000105b9d3f0 specialized _fatalErrorMessage(StaticString, StaticString, StaticString, UInt, flags : UInt32) -> Never + 96
6    SourceKittenFramework              0x00000001057b6880 NSString.CacheContainer.(lineAndCharacter(forByteOffset : Int) -> (line : Int, character : Int)?).(closure #2) + 1546
7    SourceKittenFramework              0x00000001057b6480 thunk + 56
8    SourceKittenFramework              0x00000001057c4830 partial apply for thunk + 89
9    libswiftCore.dylib                 0x0000000105a685a0 Optional.map<A> ((A) throws -> A1) throws -> A1? + 363
10   SourceKittenFramework              0x00000001057b6530 NSString.CacheContainer.lineAndCharacter(forByteOffset : Int) -> (line : Int, character : Int)? + 597
11   SourceKittenFramework              0x00000001057b74b0 NSString.lineAndCharacter(forByteOffset : Int) -> (line : Int, character : Int)? + 61
12   SwiftLintFramework                 0x0000000105432f20 Location.init(file : File, byteOffset : Int) -> Location + 297
13   SwiftLintFramework                 0x00000001054a1900 TypeNameRule.validateName(name : String, dictionary : [String : SourceKitRepresentable], file : File, offset : Int) -> [StyleViolation] + 1167
14   SwiftLintFramework                 0x00000001054a3620 TypeNameRule.(validateTypeAliasesAndAssociatedTypes(File) -> [StyleViolation]).(closure #1) + 1742
15   SwiftLintFramework                 0x00000001054a56f0 partial apply for TypeNameRule.(validateTypeAliasesAndAssociatedTypes(File) -> [StyleViolation]).(closure #1) + 302
16   SwiftLintFramework                 0x00000001054a3ee0 thunk + 65
17   SwiftLintFramework                 0x00000001054a5870 partial apply for thunk + 89
18   libswiftCore.dylib                 0x0000000105b1c8a0 Sequence.flatMap<A where ...> ((A.Iterator.Element) throws -> A1) throws -> [A1.Iterator.Element] + 639
19   SwiftLintFramework                 0x00000001054a0d60 TypeNameRule.validateTypeAliasesAndAssociatedTypes(File) -> [StyleViolation] + 648
20   SwiftLintFramework                 0x00000001054a0a90 TypeNameRule.validateFile(File) -> [StyleViolation] + 243
21   SwiftLintFramework                 0x00000001054a4a00 protocol witness for Rule.validateFile(File) -> [StyleViolation] in conformance TypeNameRule + 259
22   SwiftLintFramework                 0x0000000105374e50 Linter.(getStyleViolations(Bool) -> ([StyleViolation], [(id : String, time : Double)])).(closure #1) + 912
23   SwiftLintFramework                 0x0000000105376dd0 thunk + 42
24   SwiftLintFramework                 0x00000001053780d0 partial apply for thunk + 89
25   libswiftCore.dylib                 0x0000000105b1c8a0 Sequence.flatMap<A where ...> ((A.Iterator.Element) throws -> A1) throws -> [A1.Iterator.Element] + 639
26   SwiftLintFramework                 0x0000000105374b30 Linter.getStyleViolations(Bool) -> ([StyleViolation], [(id : String, time : Double)]) + 558
27   SwiftLintFramework                 0x0000000105374ad0 Linter.styleViolations.getter + 63
28   SwiftLintFrameworkTests            0x00000001051d7480 violations(String, config : Configuration) -> [StyleViolation] + 1189
29   SwiftLintFrameworkTests            0x00000001051e2140 XCTestCase.verifyExamples(triggers : [String], nonTriggers : [String], configuration : Configuration) -> () + 1043
30   SwiftLintFrameworkTests            0x00000001051e0040 XCTestCase.verifyRule(RuleDescription, ruleConfiguration : Any?, commentDoesntViolate : Bool, stringDoesntViolate : Bool, skipCommentTests : Bool, skipStringTests : Bool, testMultiByteOffsets : Bool) -> () + 1891
31   SwiftLintFrameworkTests            0x000000010520ea80 RulesTests.testTypeName() -> () + 686
32   SwiftLintFrameworkTests            0x000000010520ed50 @objc RulesTests.testTypeName() -> () + 34
33   CoreFoundation                     0x00007fff9a86e360 __invoking___ + 140
34   CoreFoundation                     0x00007fff9a86e150 -[NSInvocation invoke] + 289
35   XCTest                             0x00000001000ac99d __24-[XCTestCase invokeTest]_block_invoke_2 + 481
36   XCTest                             0x00000001000e6b7e -[XCTestContext performInScope:] + 190
37   XCTest                             0x00000001000ac88b -[XCTestCase invokeTest] + 255
38   XCTest                             0x00000001000acfda -[XCTestCase performTest:] + 457
39   XCTest                             0x00000001000aa0c1 -[XCTestSuite performTest:] + 491
40   XCTest                             0x00000001000aa0c1 -[XCTestSuite performTest:] + 491
41   XCTest                             0x00000001000aa0c1 -[XCTestSuite performTest:] + 491
42   XCTest                             0x0000000100096c95 __25-[XCTestDriver _runSuite]_block_invoke + 51
43   XCTest                             0x00000001000bec21 -[XCTestObservationCenter _observeTestExecutionForBlock:] + 602
44   XCTest                             0x00000001000969a7 -[XCTestDriver _runSuite] + 438
45   XCTest                             0x0000000100097655 -[XCTestDriver _checkForTestManager] + 612
46   XCTest                             0x00000001000e7e39 _XCTestMain + 628
47   xctest                             0x000000010000174b <unavailable> + 0
48   libdyld.dylib                      0x00007fffafdc9254 start + 1

[marcelofabri]

It seems that samePosition(in: content.utf16) is returning nil.

[marcelofabri]

Replacing lineAndCharacter(forByteOffset: in SourceKitten with this implementation solves the crash.

func lineAndCharacter(forByteOffset offset: Int) -> (line: Int, character: Int)? {
    let characterOffset = location(fromByteOffset: offset)
    return lineAndCharacter(forCharacterOffset: characterOffset)
}

All tests in SourceKitten pass, but I had to change OverriddenSuperCallRule.swift and ProhibitedSuperRule.swift so the markers in triggeringExamples would be after the { (they are before now). So I'm not 100% sure this is a correct change 😅

[jpsim]

Sounds like there's a bug somewhere in SourceKitten, whether it's in lineAndCharacter(forByteOffset:), location(fromByteOffset:) or lineAndCharacter(forCharacterOffset:). 😬

[marcelofabri]

It's in lineAndCharacter(forByteOffset:) 😅

[marcelofabri]

This line actually: https://github.com/jpsim/SourceKitten/blob/master/Source/SourceKittenFramework/String%2BSourceKitten.swift#L183

[marcelofabri]

Or were you referring to the +1 offset after changing the implementation? 🤔

[jpsim]

All of it. There's a bug now with lineAndCharacter(forByteOffset:) (as evidenced by this crash) and there's a bug in either location(fromByteOffset:), lineAndCharacter(forCharacterOffset:) or OverriddenSuperCall/ProhibitedSuper (as evidenced by the changed offset).

[marcelofabri]

I have no clue why only these tests are failing. I thought it could be because of \t (and maybe \n), but even after removing them I still get the failures 😭 (and the same behavior with the old implementation)

[mknabbe]

I don't know if it's still relevant. Here's my configuration.

disabled_rules: # rule identifiers to exclude from running
  - valid_docs
  - variable_name
opt_in_rules: # some rules are only opt-in
  - empty_count
excluded: # paths to ignore during linting. Takes precedence over `included`.
  - Pods

line_length: 150
type_body_length: 500

[marcelofabri]

Another example of this crash: #1068 (comment)

[SDGGiesbrecht]

Some possibly related debugging occurred in #1292 beginning with this comment.

[Coeur]

@SDGGiesbrecht I don't think it's the same thing. For #1006, the fix is said to be in this pull request: jpsim/SourceKitten#358

[jpsim]

Fixed in #1535.