Fix tag cloud visualization failing on formatted values

[bx80]

Description:

When using the tag cloud data visualization on currency values an error is shown.

"message":"Unsupported operand types: string \/ string","file":"\/var\/www\/html\/plugins\/CoreVisualizations\/Visualizations\/Cloud.php","line":197,

This is because the tag cloud is generated after the datatable filters are applied, so when the data includes currency values the visualization fails to compute tag sizes because it cannot parse formatted currency values.

This PR changes the point where the tag cloud data is generated to happen before the metric formatting filters are applied.

Ref PG-2896

Review

• Functional review done
• Potential edge cases thought about (behavior of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• Security review done
• Wording review done
• Code review done
• Tests were added if useful/possible
• Reviewed for breaking changes
• Developer changelog updated if needed
• Documentation added if needed
• Existing documentation updated if needed

[AltamashShaikh]

I checked this in 4.x-dev and it does solve the isse

[sgiehl]

Had another look at that one. Actually we are showing the value when hovering over a word from the tag cloud. So this change now actually causes the value to be displayed unformatted there. So solving this properly won't be possible unless we implement another hack that fetches the data twice, so we are able to calculate with it and display it formatted.

Overall this is another case why #20701 and/or #20702 would be such important to implement, as currently we need to produce more and more technical debts to fix such issues... (ping @Stan-vw)

[bx80]

Huge upvote for #20701 / #20702 👍 Everytime we encounter this problem and implement a workaround we've creating more work for later.

I've implemented a hack which avoids reloading the datatable, it works like this:

• beforeLoadDataTable() sets ['format_metrics'] = 0;
• Datatable is loaded, no metric formatting is done
• afterAllFiltersAreApplied() gets the unformatted values from the datatable and stores them in an array
• beforeRender() sets ['format_metrics'] = 1; and calls a new method applyMetricsFormatting() on the Visualization class which applies just the metric formatting filter to the loaded dataset.
• beforeRender() finally calls generateCloudData() which uses both the stored unformatted values and the now formatted values from the dataset to build the tag cloud data.

This allows the tag cloud to be built properly when using currency or other formatted values and still show the correctly formatted values when hovering.

I know the Visualization::applyMetricsFormatting() method is an ugly approach, but it's a simple and performant workaround for visualization that need to build things with both formatted and unformatted data. I've made a note on the method that it is a workaround and may be removed once we have a proper solution for this issue.

[sgiehl]

The workaround seems to work. At least for custom reports, as they are using mainly processed metrics, which are correctly formatted.
Metrics in other reports aren't formatted. But that hadn't been the case before already. That another problem of formatting some metrics in the post processor, but all other metrics in the view. But that's not something we need to solve here.

[AltamashShaikh]

@sgiehl @bx80 Can we cherrypick this into 4.x-dev so thatw e can solve the issue for CLOUD ?