Unable to get list of map layers from a map item in the layout

[qgib]

Author Name: Harrissou Santanna (@DelazJ)
Original Redmine Issue: 19736
Affected QGIS version: 3.3(master)
Redmine category:expressions

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If I write in a label item of the layout an expression like @map_get(item_variables('Map 1'), 'map_scale')@ it returns the current scale of the "Map 1" item.
If I write @map_get(item_variables('Map 1'), 'map_layers')@, I get an empty label. Same thing with map_layer_ids.

[qgib]

Author Name: Nyall Dawson (@nyalldawson)

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That's because the values aren't strings or numbers - you need to format them by converting the list to a string, etc. It's the same behaviour with geometries, dates, intervals, etc.

[qgib]

Author Name: Harrissou Santanna (@DelazJ)

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Ok I get it using something like @array_to_string( array_foreach( map_get( item_variables( 'Map 1' ), 'map_layers'), layer_property(@element, 'name')))@.
Just awesome!!! Thanks.

Then I remark that I get all the layers checked in the Layers panel and not only the layers whose features are visible in the map item. Likewise, when I lock the map item with a map_theme i get the map theme layers (regardless what is displayed in the main canvas, which is great).
BUT I wonder if there should not be a method to filter list of layers by map item content (like the legend item option).

[qgib]

Author Name: Nyall Dawson (@nyalldawson)

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Ok, but that's a feature request ;)

[qgib]

Author Name: Harrissou Santanna (@DelazJ)

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Done in #27570

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• status_id was changed from Open to Closed

[qgib]

Author Name: Giovanni Manghi (@gioman)

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• resolution was changed from to invalid