Cant add Pie Chart to dashboard on Formula and Breakdown-by

[sholinaty]

Bug description

An error is displayed if the following conditions are met when adding a chart to a dashboard:

• multiple data items
• a formula (A + B + C )
• a Breakdown by: (device type)
• the data only currently has one device type

Expected behavior

a pie chart with 1 item, consuming 100% of the pie.

How to reproduce

1. create a new graph
2. set a formula
3. have a breakdown by: with only one item
4. try to add it as a Pie Chart.

Environment

• PostHog Cloud
• self-hosted PostHog (ClickHouse-based), version/commit: please provide
• self-hosted PostHog (Postgres-based, legacy), version/commit: please provide

[sholinaty]

I can successfully have 3 datapoints with a Breakdown-by:

however, I can NOT have a Formula (A+B+C) with a breakdown-by:

[sholinaty]

@paolodamico any updates on this?