cover: Fix a race condition in how the server is started as part of a call #9124
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… call
[Why]
Before sending a message to the cover server, the `call` function checks
if the server is running, starting it if it does not.
However, there is no locking/atomicity between the check and the start.
If there is a concurrent call, the server might be started in parallel
by another process and the `start()` call would return
`{already_started, _}`. This causes the function to fail with the
`badmatch` exception.
[How]
The code now accepts that the server is running after seeing the server
as stopped and retrying the call.
CT Test Results 2 files 22 suites 6m 6s ⏱️ Results for commit 9587c7a. ♻️ This comment has been updated with latest results. To speed up review, make sure that you have read Contributing to Erlang/OTP and that all checks pass. See the TESTING and DEVELOPMENT HowTo guides for details about how to run test locally. Artifacts// Erlang/OTP Github Action Bot |
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Why
Before sending a message to the cover server, the
callfunction checks if the server is running, starting it if it does not.However, there is no locking/atomicity between the check and the start. If there is a concurrent call, the server might be started in parallel by another process and the
start()call would return{already_started, _}. This causes the function to fail with thebadmatchexception.How
The code now accepts that the server is running after seeing the server as stopped and retrying the call.