XCode compilation error: Command failed due to signal: Segmentation fault: 11

DarioJG

Hi, 

After migrating to Swift 3 using XCode 8.3.2 and Dropbox SDK 3.0.9 (Objective-C version) I am getting the mentioned error in 1 of the files. Further investigation shows the error is caused by this piece of code:

 

        let listFolderResponseHandler : DBRpcResponseBlock = { response, routeError, networkError in
            if let listFolderResult = response {
                completionHandler(DropboxFolderMetadata(withPath: folderPath, listFolderResult: listFolderResult), nil, nil)
            } else if let error = routeError {
                completionHandler(nil, error, nil)
            } else if let netError = networkError {
                completionHandler(nil, nil, netError)
            }
        }

 

 

Replacing that line with this:

 

let listFolderResponseHandler: DBRpcResponseBlock? = nil

Still generates the error. BUT, commenting any of those out, gets rid of the error.

 

This is the context where that code exists:

import Foundation
import ObjectiveDropboxOfficial

struct DropboxHelper {

   //Other functions    

    static func list(folder folderPath: String, cursor folderCursor: String?, completionHandler: @escaping (DropboxFolderMetadata?, DBFILESListFolderError?, DBRequestError?) -> Void) {
        guard let client = DBClientsManager.authorizedClient() else { return }

        let listFolderResponseHandler : DBRpcResponseBlock = { response, routeError, networkError in
            if let listFolderResult = response {
                completionHandler(DropboxFolderMetadata(withPath: folderPath, listFolderResult: listFolderResult), nil, nil)
            } else if let error = routeError {
                completionHandler(nil, error, nil)
            } else if let netError = networkError {
                completionHandler(nil, nil, netError)
            }
        }

        //additional code commented right now
    }

    ...
}

Looking further in the error log I get this message as the operation that was been executed when the error occured:

While emitting SIL for 'list' at <path>/Dropbox.swift:30:5

 

And stack dump:

0  swift                    0x00000001094154f7 PrintStackTraceSignalHandler(void*) + 39
1  swift                    0x00000001094149a6 SignalHandler(int) + 646
2  libsystem_platform.dylib 0x00007fffca086b3a _sigtramp + 26
3  libsystem_platform.dylib 0x000000010e9c2a00 _sigtramp + 1150533344
4  swift                    0x000000010726627e swift::NominalTypeDecl::hasFixedLayout() const + 14
5  swift                    0x0000000106e67172 (anonymous namespace)::LowerType::visitAnyStructType(swift::CanType, swift::StructDecl*) + 50
6  swift                    0x0000000106e6677c swift::Lowering::TypeConverter::getTypeLoweringForUncachedLoweredType(swift::Lowering::TypeConverter::TypeKey) + 76
7  swift                    0x0000000106e65fb8 swift::Lowering::TypeConverter::getTypeLowering(swift::Lowering::AbstractionPattern, swift::Type, unsigned int) + 2328
8  swift                    0x0000000106a6303d swift::Lowering::SILGenFunction::emitLocalVariableWithCleanup(swift::VarDecl*, bool, unsigned int) + 189
9  swift                    0x0000000106a62402 swift::Lowering::SILGenFunction::emitInitializationForVarDecl(swift::VarDecl*) + 338
10 swift                    0x0000000106a64673 swift::Lowering::SILGenFunction::emitPatternBinding(swift::PatternBindingDecl*, unsigned int) + 83
11 swift                    0x0000000106ad3ee8 swift::ASTVisitor<(anonymous namespace)::StmtEmitter, void, void, void, void, void, void>::visit(swift::Stmt*) + 14712
12 swift                    0x0000000106a93509 swift::Lowering::SILGenFunction::emitFunction(swift::FuncDecl*) + 409
13 swift                    0x0000000106a1489b swift::Lowering::SILGenModule::emitFunction(swift::FuncDecl*)::$_1::operator()(swift::SILFunction*) const + 1867
14 swift                    0x0000000106a138a2 swift::Lowering::SILGenModule::emitFunction(swift::FuncDecl*) + 642
15 swift                    0x0000000106ad8efb (anonymous namespace)::SILGenType::emitType() + 971
16 swift                    0x0000000106ad8acd swift::Lowering::SILGenModule::visitNominalTypeDecl(swift::NominalTypeDecl*) + 29
17 swift                    0x0000000106a20ecb swift::Lowering::SILGenModule::emitSourceFile(swift::SourceFile*, unsigned int) + 1483
18 swift                    0x0000000106a22aa9 swift::SILModule::constructSIL(swift::ModuleDecl*, swift::SILOptions&, swift::FileUnit*, llvm::Optional<unsigned int>, bool, bool) + 1593
19 swift                    0x0000000106233604 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 42516
20 swift                    0x00000001061e2d6c main + 9052
21 libdyld.dylib            0x00007fffc9e77235 start + 1
22 libdyld.dylib            0x00000000000000c1 start + 907579021
Stack dump:

Any idea what might be the cause of this error?

Greg-DB

Thanks for the detailed report! I'm not sure what the issue may be off hand. The team will look into it and we'll follow up here once we have an update for you.