completion stops working after error

[wibed]

i have made the experience that after opening a .swift file
and setting the project's root dir i get successful completion

but after one interrupts the completion by keep typing an error occurs,
and no more completion after that.
I suspect it is because sourcekit-lsp crashed

swift version: 5.4.2

lsp error message:

# Table of Contents
2021-07-19 08:11:59.454 sourcekit-lsp[62:ef66e700] triggerFromIncompleteCompletions with incompatible completion session; expected DocumentURI(storage: <file:///work/cards/service/api/Sources/api/User/ControllerUser.swift>)@1215, but got DocumentURI(storage: <file:///work/cards/service/api/Sources/api/User/ControllerUser.swift>)@1224

company error message:

Company: An error occurred in auto-begin
Company: backend (company-capf :with company-yasnippet) error “request cancelled” with args (candidates fun)

second lsp error message:

2021-07-19 11:00:04.025 sourcekit-lsp[82:8ffff700] error response (Request Failed): codecomplete.open: code completion session for ’/work/cards/service/api/Sources/api/User/Controller+User.swift’, 1166 already exists

backtrace:

• 1
• 2

stacktrace:

• 1
• the second got too long to post

after installing a missing dependency libpython2.7 the error still persists.
namely that the lsp server becomes unresponsive.and completion stops working

additionally i tried:

• successfully build the project before provoking the error
• built sourcekit-lsp from source
  • backtrace
  • stacktrace
• downgraded swift to 5.4
• used no included framework vanilla swift from swift package init
  • lsp log
  • backtrace
  • stacktrace

it seems the trace shows nothing but the empty response from the sourcekit-lsp server.
the error messages differ only from the DocumentURI (which is the same for
expected and for received) and the char number @1151 (which differs between expected and received).

[wibed]

i started over and created a clean reproduction of the error:

i am typing func for function check the popup and
select the "func" option.

after the selection from the menu starts a snippet out of the full stacktrace

https://termbin.com/kwyw

in the snippet i type in the function name "hello", followed by the parentheses. as first argument i intent to write out "name", but at the second char ("na") the error pops off.

in the end it looks like this:

func hello(na)
            ^ -->> Error pops off after typing "a"

i included a follow up request for code completion, including context, in the stacktrace and the empty response thereafter.

it seems after the return message "request cancelled" with the code "-32800" the process sourcekit-lsp only provides empty responses.

this is accredited with the following error message out of stderr

2021-07-21 02:46:22.001 sourcekit-lsp[47:a15a5700] triggerFromIncompleteCompletions with incompatible completion session; expected DocumentURI(storage: \url{file:///work/cards/service/test/Sources/test/main.swift})@29, but got DocumentURI(storage: \url{file:///work/cards/service/test/Sources/test/main.swift})@35

the full stacktrace is to be found here:
https://termbin.com/0x2n

[wibed]

my assumption grows the responsibility relies on the client side for this behavior.
here is a backtrace:
https://termbin.com/5dkr

[wibed]

opened an issue on lsp-mode
emacs-lsp/lsp-mode#3028