Fix Groupby display name for Valuedrift metrics

[Sudharsan-T]

Fix GroupBy display name for ValueDrift metrics

Problem

GroupBy(ValueDrift(...)) does not include the group-by column name and label in the report display name, while other metrics such as MaxValue do.

This results in inconsistent output:

• GroupBy(MaxValue(...)) → includes group-by column and label
• GroupBy(ValueDrift(...)) → shows only Drift in column '<column>'

Reported in #1706.

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Root cause

GroupByMetricCalculation relied on metric-specific internal display name generation. For ValueDrift, this display name does not carry group-by context, so the column name and label were lost.

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Fix

Build the display name explicitly in GroupByMetricCalculation.display_name() using:

• the base display name of the underlying metric
• the group-by column name
• the group label

This makes the behavior consistent across all GroupBy metrics.

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Implementation

File:

src/evidently/metrics/group_by.py

The display name construction was moved to the GroupBy calculation layer instead of relying on metric-specific behavior.

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Result

GroupBy(ValueDrift(...)) now displays:

Drift in column '<column>' group by '<group_column>' for label: '<label>'

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Testing

• Reproduced the issue locally using the example from GroupBy(ValueDrift) display_name not shown properly #1706
• Verified output for both MaxValue and ValueDrift
• Formatting and lint checks pass

[DimaAmega]

Hi @Sudharsan-T

Here we see less information than before, so this also needs to be fixed

Check html-visual-testing-playwright-report

[Liraim]

Hi @Sudharsan-T,

Thanks for the PR and for working on this improvement.

As @DimaAmega mentioned, there is one important issue I want to highlight, and why it occurs:

• GroupBy wrapper relies on renders of underlying metrics to create a widget in the report. To customize the display name, it replaces the display_name() with a patched version (using _patched_display_name)
• In this PR, this patched method was removed, which means every metric rendered through GroupBy loses the patched display_name and therefore its group-by-specific label.

To fix this properly, I think the following changes are needed:

• bring back the use of _patched_display_name in the group-by wrapper
• update the render method in ValueDriftCalculation (src/evidently/metrics/column_statistics.py:588) to use self.display_name() method instead of the hardcoded string
• update self.display_name() to return proper string (it seems now it uses a different text from what is used in render).

This should restore the expected behavior for all metrics, and ValueDrift metrics correctly display the group-by text when used inside GroupBy.