[Lens] Consolidate and improve consistency when presenting warnings and errors

[MichaelMarcialis]

Lens currently presents warnings and errors in inconsistent ways. Within the Lens editor, warnings are listed in a warning popover that is triggered by a warning count button in the toolbar area. Errors can be either shown directly on the workspace or on individual dimension items. Outside of the Lens editor (in dashboards or embeddables), warnings are again listed in a warning popover that is triggered by a warning count button in the bottom-left corner of the visualization. Errors are only shown in the workspace. I think some improvements could be made on our part to consolidate warnings and errors together and ensure they are presented in a consistent and predictable manner for our users.

Additionally, per conversations happening within the related issues listed below, we're now discussing the possibility of allowing visualizations to still be rendered (if possible), regardless of the presence of errors/warnings. This would allow us to to at least show users what we are able to in instances where other aspects of a visualization can still be rendered and possibly be of value (will be beneficial for solutions and integration dashboards). Assuming we proceed with this direction, we can no longer assume that the workspace will be a viable place to house error messaging. In addition to the aforementioned desire consolidate and bring consistency to our presentation of errors and warnings, I'm thinking it may be prudent to explore the following:

• Within the Lens editor, add the ability to display a warning or an error on an offending dimension item (or dimension group) whenever possible (whereas we currently only do this for errors).

• Within the Lens editor and for dashboard/embedded Lens visualizations, list both errors and warnings in a popover triggered by an error/warning count button (whereas we currently only do this for warnings). This list can include all general visualization errors and warnings as well as those that are specific to individual dimensions (even if it repeats issues already shown at individual dimension items).

• In both of the above scenarios, make it clear to distinguish between error and warning using iconography, color, etc.

If this is of interest, we'll need to come up with some concrete criteria to determine what is a warning versus what is an error. My current thinking is that anything that is always going to be unexpected or undesired by a user should always be considered an error (ex. deletion of a runtime field that was used in a dimension aggregation). Alternatively, if the issue isn't guaranteed to be unexpected or undesired but we want the user to be made aware, it should be considered a warning (ex. unexpected arrays values present in a field).

This will likely require some degree of design support for the creation of new iconography and guidance on how these consolidated warnings and errors should appear in different locations/scenarios.

Error in workspace example

Error on dimension item example

Warning in toolbar example

Related issues:

• [Lens] Don't block render on missing field validation errors  #143673
• [Lens] allow rendering despite invalid dimensions/layers #144906

CCing @andrewctate.

[elasticmachine]

Pinging @elastic/kibana-visualizations @elastic/kibana-visualizations-external (Team:Visualizations)