Getting a Segmentation fault: 11 with Swift 5.2 when using FileManager.default.currentDirectoryPath

Question

I've got a custom Swift script that is similar to the following:

#!/usr/bin/env xcrun --sdk macosx swift

import Foundation

let path = FileManager.default.currentDirectoryPath

On Swift 5.1 and lower it runs just fine, but upon updating to Swift 5.2, I get

0. Program arguments: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift -frontend -interpret test.swift -enable-objc-interop -stack-check -sdk /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk -color-diagnostics -module-name test 
1. Apple Swift version 5.2 (swiftlang-1103.0.32.1 clang-1103.0.32.29)
2. While running user code "test.swift"
0 swift 0x000000010dd2f4ea PrintStackTraceSignalHandler(void*) + 42
1 swift 0x000000010dd2ecc0 SignalHandler(int) + 352
2 libsystem_platform.dylib 0x00007fff6710f42d _sigtramp + 29
3 libsystem_platform.dylib 0x00007ffee6222018 _sigtramp + 2131831816
4 swift 0x0000000109ab29ba llvm::MCJIT::runFunction(llvm::Function*, llvm::ArrayRef<llvm::GenericValue>) + 458
5 swift 0x0000000109ab9a2b llvm::ExecutionEngine::runFunctionAsMain(llvm::Function*, std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > const&, char const* const*) + 2011
6 swift 0x0000000109a8eaea performCompileStepsPostSILGen(swift::CompilerInstance&, swift::CompilerInvocation&, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule> >, bool, llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, swift::PrimarySpecificPaths const&, bool, int&, swift::FrontendObserver*, swift::UnifiedStatsReporter*) + 14362
7 swift 0x0000000109a834a5 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 55813
8 swift 0x00000001099f94d3 main + 1283
9 libdyld.dylib 0x00007fff66f167fd start + 1
10 libdyld.dylib 0x000000000000000b start + 2567870479
Segmentation fault: 11

Have there been any breaking changes that I'm not aware of?

Answer 1

Turns out that in this case, the problem was in rogue overlay dylibs that were in place because I've been using SwiftGen.

The solution is to either uninstall SwiftGen by calling

brew uninstall swiftgen

or following Nikolaj's answer from Swift bug tracking system by reinstalling SwiftGen with

--build-from-source

option and removing the dylibs from "lib" folder.