"Template variable Service failed" on empty Kusto queries

[mcmon-dev]

Steps to reproduce the bug

1. Create a new panel with Azure Monitor as data source
2. Create a new query where Service is set to Azure Log Analytics
3. Write a Kusto query where valid results are returned
4. Add another Kusto query where no results are returned

Resulting and expected behaviour
As a result I get the following error message. It is popping up on every refresh of the panel.

The expected behaviour would be to not have this error message. It would also be convenient to have an option to either show the label name in the legend or hide labels with no data.

System information

• Grafana: v7.3.1
• Discrete Panel: 0.1.0

[mcmon-dev]

I managed to fix this problem by changing line 360 in src/module.ts from if (time) { to if (time && frame.length > 0) {. frame.length > 0 filters out all frames which don't contain values.