Is this REPL issue a bug or specific to my environment?

Using Swift
,
1

I've been encountering an issue with the Swift REPL for a while now, and chalked it up to being some kind of issue with my local environment. That is, until I got a new computer and the issue was happening there too. This has been happening consistently with Swift 5.2.4/Xcode 11 and Swift 5.3/Xcode 12. Stranger still, it used to not happen with Swift 5.2.4 - but then just started seemingly out of nowhere.

The Swift REPL consistently complains when I try to import SwiftPM modules, saying that it can't lookup the symbols. This is strange, but the code has no problem running in tests — just the REPL.

Here's a quick example of how to maybe reproduce this. For me, it happens with any SwiftPM library, so the specific one doesn't matter.

$ mkdir Example
$ cd Example
$ swift package init --type library

Edit Sources/Example/Example.swift to look like so:

public struct Example {
    var text = "Hello, world!"
    public init() {}
}

Next, launch the REPL.

$ swift run --repl
...
1> #if canImport(Example)
2. print("Proceed")
3. #endif
Proceed
4> import Example
5> let example = Example()
example: Example.Example = {
  text = {
    _guts = {
      _object = {
        _countAndFlagsBits = <extracting data from value failed>

        _object = <extracting data from value failed>

      }
    }
  }
}
error: Couldn't lookup symbols:
  Example.Example.init() -> Example.Example
  Example.Example.init() -> Example.Example

It's really strange, isn't it?

If it's helpful I can include a log of what LLDB logs, but it's a lot. Let me know if anyone else is having this issue or what I can do to fix it! Thanks.

2

It doesn't reproduce on my system (in case that is interesting to know):

...
$ swift run --repl
[3/3] Linking libExample__REPL.dylib
Launching Swift REPL with arguments: -I/Users/jens/swifttest/Example/.build/x86_64-apple-macosx/debug -L/Users/jens/swifttest/Example/.build/x86_64-apple-macosx/debug -lExample__REPL
Welcome to Apple Swift version 5.3 (swiftlang-1200.0.29.2 clang-1200.0.30.1).
Type :help for assistance.
  1> #if canImport(Example) 
  2. print("Proceed") 
  3. #endif
Proceed
  4> import Example
  5> let example = Example()
example: Example.Example = {
  text = "Hello, World!"
}
  6>
3

Bummer! Thanks for letting me know. I suspected it was something local rather than a proper bug. I wonder what could be going wrong on both of the computers that I'm trying it on... It's especially odd because the second computer is brand new. Hmm...

4

So in case someone stumbles by this in the future with the same issue -- I'm not 100% sure what caused it but I believe it was a privacy/security issue. I think I had tried to do some debugging in Xcode and got asked "Developer tools needs to take over another process for debugging" (or something of that sort). After giving that permission I noticed later that the REPL was working again for me. I believe this is what fixed the issue though, given that the REPL is built on LLDB.

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