api: test_details with correct querying for cross-variant

pkg/api/componentreadiness/test_details.go

@@ -139,9 +139,34 @@ func (c *componentReportGenerator) getTestDetailsQuery(allJobVariants crtype.Job
 	for group, variant := range c.RequestedVariants {
 		queryString += fmt.Sprintf(` AND jv_%s.variant_value = '%s'`, api.CleanseSqlName(group), api.CleanseSqlName(variant))
 	}
+	if isSample {
+		queryString += filterByCrossCompareVariants(c.VariantCrossCompare, c.CompareVariants, &commonParams)
+	} else {
+		queryString += filterByCrossCompareVariants(c.VariantCrossCompare, c.IncludeVariants, &commonParams)
+	}
 	return queryString, groupString, commonParams
 }
 
+// filterByCrossCompareVariants adds the where clause for any variants being cross-compared (which are not included in RequiredVariants).
+// As a side effect, it also appends any necessary parameters for the clause.
+func filterByCrossCompareVariants(crossCompare []string, variantGroups map[string][]string, params *[]bigquery2.QueryParameter) (whereClause string) {
+	if len(variantGroups) == 0 {
+		return // avoid possible nil pointer dereference
+	}
+	for _, group := range crossCompare {
+		if variants := variantGroups[group]; len(variants) > 0 {
+			group = api.CleanseSqlName(group)
+			paramName := "CrossVariants" + group
+			whereClause += fmt.Sprintf(` AND jv_%s.variant_value IN UNNEST(@%s)`, group, paramName)
+			*params = append(*params, bigquery2.QueryParameter{
+				Name:  paramName,
+				Value: variants,
+			})
+		}
+	}
+	return
+}
+
 type baseJobRunTestStatusGenerator struct {
 	commonQuery              string
 	groupByQuery             string