[SR-10303] Swift CLI (REPL) on fresh Ubuntu seems broken

[swift-ci]

Previous ID	SR-10303
Radar	None
Original Reporter	freak4pc (JIRA User)
Type	Bug

Additional Detail from JIRA

Votes	0
Component/s	Compiler, LLDB for Swift
Labels	Bug
Assignee	None
Priority	Medium

md5: 5efc473d44b9885839772e54f92cf230

Issue Description:

Fresh Ubuntu 18.04 installation on Docker, using instructions from Swift.org https://swift.org/download/#using-downloads

Running `swift` prints out:

root@d111086a94ff:~# swift
error: failed to launch REPL process: process launch failed: 'A' packet returned an error: 8

[weissi]

freak4pc (JIRA User) this happens if you run it in docker and your container isn't privileged. Swift's REPL needs a privileged container because it uses ptrace to attach to another process.
if you do

docker run -it --rm --privileged swift:5.0

it should work. However, please be aware that this has some security implications: https://docs.docker.com/engine/reference/run/#runtime-privilege-and-linux-capabilities

In local development the security implications should be okay though 🙂

[swift-ci]

Comment by Shai Mishali (JIRA)

Thanks Johannes!
That seems to do the trick. Maybe a better error message is in order?

[belkadan]

@dcci, how hard do you think it would be to detect this situation?

[dcci]

I think it's feasible. Let me see what I can do.