Unexpected Logger output location

[zolrath]

Environment

• Elixir & Erlang/OTP versions (elixir --version): 1.14.2 Erlang/OTP 24
• Operating system: Fly.io Livebook Docker Image Linux
• How have you started Livebook (mix phx.server, livebook CLI, Docker, etc): Docker
• Livebook version (use git rev-parse HEAD if running with mix): v0.8.0
• Browsers that reproduce this bug (the more the merrier): Chrome

Current behavior

When outputting a cell only containing multiple Logger messages they are separated in different Kino frames.

In this example, the first Logger output is listed in the top frame with the remaining Logger outputs in the second frame. If there is an expression above the Logger outputs, they all appear in the same frame.

https://user-images.githubusercontent.com/454563/209405622-044cdeac-2501-407f-a88a-fd9c84f0756b.mov

It didn't happen during recording, but I had an instance where the output changed if there was a new line between the 1 + 1 and the Logger statement, requiring a blank line between the two for the Logger output to move to the end frame.

Expected behavior

I would expect all Logger outputs to be grouped, regardless of their placement in the cell/other codes presence.

[jonatanklosko]

Hey @zolrath! Logger works asynchronously, so this is not exactly deterministic. You could do Logger.configure(sync_threshold: 0) to make sure every log is synchronous.

[zolrath]

Hey @zolrath! Logger works asynchronously, so this is not exactly deterministic. You could do Logger.configure(sync_threshold: 0) to make sure every log is synchronous.

Ahh, that makes sense. This was for a specific example Livebook, so that option works perfectly, thanks!