DataFrame: Align frame (__series.name) and field naming (__field.name)

[torkelo]

There is a big mismatch in how we handle getFrameDisplayName and getFieldDisplayName. The problem is pretty big because we use getFrameDisplayName to evaluate ${__series.name} (which is a macro we do show first in data link auto-complete menu).

The current logic for getFrameDisplayName results in a very different name compared to getFieldDisplayName (Which we use almost everywhere else for the value field of a single time series frame).

So for time series with 2 fields (time, value) and the value field has say a displayName or displayNameFromDS ${__series.name} will currently just result in Series (<refId>) which is pretty far from the display name actually used in all visualizations (which is the getFieldDisplayName for the value field).

Changes

• Update getFrameDisplayName to return the result of the getFieldDisplayName for DataFrames with only a single value field.

This could be a pretty big breaking change as it changes frame display names. not really sure where we use frame display names where it could cause a breaking change (other than in data links that use ${__series.name} and are counting on the bad current behavior.

Escalation where I discovered this
https://github.com/grafana/support-escalations/issues/6199

Release notice breaking change

The implementation for template macro ${__series.name} was not always correct, resulting in an interpolation that was very different from the series name displayed in the visualization. We have now fixed this issue so that it does show the same name. Depending on how ${__series.name} is used this could result in a minor breaking change.

[dprokop]

@torkelo I think this change looks good, tho I see two potential places where we need to check whether or not this is introducing some bugs:

• seriesToRows transform https://github.com/grafana/grafana/blob/frame-name-field-name-alignment/packages/grafana-data/src/transformations/transformers/seriesToRows.ts#L79 cc @bohandley
• Explore graph that uses getFrameDisplayName for hiding the series. It's used indirectly via Logs volume visualization. Would be good to get @ifrost eyes on this PR. Adding as a reviewer.

[ifrost]

Explore graph that uses getFrameDisplayName for hiding the series. It's used indirectly via Logs volume visualization. Would be good to get @ifrost eyes on this PR. Adding as a reviewer.

Thanks for tagging! Logs volume uses frame.name so this change shouldn't affect it. I tested it locally and it seems to work fine 👍 (cc @grafana/observability-logs)

[bohandley]

This looks good to me, but does not solve the Prometheus issue where the Frame.name takes precedence over the custom legend format option when we use getFrameDisplayName. This is only in the Series to Rows transformation as far as I know, so we can still prioritize displayNameFromDS directly in that transformation if we don't want to do that here.

#69343