Using rally app lookback API - unable to fetch defects that are tagged

Question

I am using rally lookback API and creating a defect trend chart. I need to filter defects that do not have a tag "xyz".

Using the following:

this.myTrendChart = Ext.create('Rally.ui.chart.Chart', {
            storeType: 'Rally.data.lookback.SnapshotStore',
            storeConfig: {
                find: {
                    _TypeHierarchy: "Defect",
                     State: { $lt: "Closed"},
                     Tags.Name: { $nin: ["xyz"] }, 
                    _ProjectHierarchy: projectOid,
                    _ValidFrom: {$gte: startDateUTC}
                }
            },
            calculatorType: 'Calci',
            calculatorConfig: {},
            chartConfig: {
                chart: {
                    zoomType: 'x',
                    type: 'line'
                },
                title: {
                    text: 'Defect trend'
                },
                xAxis: {
                    type: 'datetime',
                    minTickInterval: 7
                },
                yAxis: {
                    title: {
                    text: 'Number of Defects'
                    }
                }
            }
        });

This does not return any data. Need help with the filter for tags.

Answer 1

Tags is a collection of tag-oids so you'll need to find and use the oid of the tag vs the name, at which point it'll just be Tags: { $nin: [oid] }. Caveat: technically, due to how expensive it is, $nin is unsupported (https://rally1.rallydev.com/analytics/doc/#/manual/48e0589f681160fc316a8a4802dc389f)...but it doesn't throw an error so maybe it works anyway.