Dashboard Schema v1beta1 to v2alpha1: Preserve string template variable datasource references in query variables (#115516)

* Dashboard migration: preserve legacy string datasource references

Fix v1beta1 → v2alpha1 conversion to handle legacy string datasource
references in QueryVariable, AdhocVariable, and GroupByVariable.

Previously, string datasource references (both template variables like
"$datasource" and direct names/UIDs like "prometheus") were being
dropped during conversion, causing variable chaining to break.

The frontend's DatasourceSrv.getInstanceSettings() already handles
string references by trying uid → name → id lookup at runtime, so we
preserve the string in the uid field and let the frontend resolve it.

* trigger frontend ci tests when dashboard migration code changes

* v1: if string convert to DS ref

* Update migration testdata to fix template variable datasource references

* update

.github/actions/change-detection/action.yml

@@ -95,6 +95,7 @@ runs:
             - 'nx.json'
             - 'tsconfig.json'
             - '.yarn/**'
+            - 'apps/dashboard/pkg/migration/**'
             - '${{ inputs.self }}'
           e2e:
             - 'e2e/**'

apps/dashboard/pkg/migration/conversion/testdata/migrated_dashboards_output/v1beta1-mig-v15.mimir_rollout_debugging.v42.v0alpha1.json

@@ -743,7 +743,9 @@
             "text": "prod",
             "value": "prod"
           },
-          "datasource": "$datasource",
+          "datasource": {
+            "uid": "$datasource"
+          },
           "hide": 0,
           "includeAll": true,
           "label": "cluster",
@@ -764,7 +766,9 @@
             "text": "prod",
             "value": "prod"
           },
-          "datasource": "$datasource",
+          "datasource": {
+            "uid": "$datasource"
+          },
           "hide": 0,
           "includeAll": false,
           "label": "namespace",

apps/dashboard/pkg/migration/conversion/testdata/migrated_dashboards_output/v1beta1-mig-v15.mimir_rollout_debugging.v42.v2alpha1.json

@@ -961,8 +961,12 @@
           "hide": "dontHide",
           "refresh": "onDashboardLoad",
           "skipUrlSync": false,
+          "datasource": {
+            "type": "",
+            "uid": "$datasource"
+          },
           "query": {
-            "kind": "prometheus",
+            "kind": "",
             "spec": {
               "__legacyStringValue": "label_values(up, job)"
             }
@@ -988,8 +992,12 @@
           "hide": "dontHide",
           "refresh": "onDashboardLoad",
           "skipUrlSync": false,
+          "datasource": {
+            "type": "",
+            "uid": "$datasource"
+          },
           "query": {
-            "kind": "prometheus",
+            "kind": "",
             "spec": {
               "__legacyStringValue": "label_values(up{job=~\"$cluster\"}, instance)"
             }

apps/dashboard/pkg/migration/conversion/testdata/migrated_dashboards_output/v1beta1-mig-v15.mimir_rollout_debugging.v42.v2beta1.json

@@ -978,8 +978,11 @@
           "skipUrlSync": false,
           "query": {
             "kind": "DataQuery",
-            "group": "prometheus",
+            "group": "",
             "version": "v0",
+            "datasource": {
+              "name": "$datasource"
+            },
             "spec": {
               "__legacyStringValue": "label_values(up, job)"
             }
@@ -1007,8 +1010,11 @@
           "skipUrlSync": false,
           "query": {
             "kind": "DataQuery",
-            "group": "prometheus",
+            "group": "",
             "version": "v0",
+            "datasource": {
+              "name": "$datasource"
+            },
             "spec": {
               "__legacyStringValue": "label_values(up{job=~\"$cluster\"}, instance)"
             }

apps/dashboard/pkg/migration/conversion/v0alpha1_to_v1beta1.go

@@ -2,6 +2,7 @@ package conversion
 
 import (
 	"context"
+	"strings"
 
 	"k8s.io/apimachinery/pkg/conversion"
 	"k8s.io/apiserver/pkg/endpoints/request"
@@ -79,5 +80,57 @@ func ConvertDashboard_V0_to_V1beta1(in *dashv0.Dashboard, out *dashv1.Dashboard,
 		return schemaversion.NewMigrationError(err.Error(), schemaversion.GetSchemaVersion(in.Spec.Object), schemaversion.LATEST_VERSION, "Convert_V0_to_V1")
 	}
 
+	// Normalize template variable datasources from string to object format
+	// This handles legacy dashboards where query variables have datasource: "$datasource" (string)
+	// instead of datasource: { uid: "$datasource" } (object)
+	// our migration pipeline in v36 doesn't address because this was not addressed historically
+	// in DashboardMigrator - see public/app/features/dashboard/state/DashboardMigrator.ts#L607
+	// Which means that we have schemaVersion: 42 dashboards where datasource variable references are still strings
+	normalizeTemplateVariableDatasources(out.Spec.Object)
+
 	return nil
 }
+
+// normalizeTemplateVariableDatasources converts template variable string datasources to object format.
+// Legacy dashboards may have query variables with datasource: "$datasource" (string).
+// This normalizes them to datasource: { uid: "$datasource" } for consistent V1→V2 conversion.
+func normalizeTemplateVariableDatasources(dashboard map[string]interface{}) {
+	templating, ok := dashboard["templating"].(map[string]interface{})
+	if !ok {
+		return
+	}
+
+	list, ok := templating["list"].([]interface{})
+	if !ok {
+		return
+	}
+
+	for _, variable := range list {
+		varMap, ok := variable.(map[string]interface{})
+		if !ok {
+			continue
+		}
+
+		varType, _ := varMap["type"].(string)
+		if varType != "query" {
+			continue
+		}
+
+		ds := varMap["datasource"]
+		if dsStr, ok := ds.(string); ok && isTemplateVariableRef(dsStr) {
+			// Convert string template variable reference to object format
+			varMap["datasource"] = map[string]interface{}{
+				"uid": dsStr,
+			}
+		}
+	}
+}
+
+// isTemplateVariableRef checks if a string is a Grafana template variable reference.
+// Template variables can be in the form: $varname or ${varname}
+func isTemplateVariableRef(s string) bool {
+	if s == "" {
+		return false
+	}
+	return strings.HasPrefix(s, "$") || strings.HasPrefix(s, "${")
+}

apps/dashboard/pkg/migration/conversion/v1beta1_to_v2alpha1.go

@@ -1185,6 +1185,10 @@ func buildQueryVariable(ctx context.Context, varMap map[string]interface{}, comm
 			// If no UID and no type, use default
 			datasourceType = getDefaultDatasourceType(ctx, dsIndexProvider)
 		}
+	} else if dsStr, ok := datasource.(string); ok && isTemplateVariable(dsStr) {
+		// Handle datasource variable reference (e.g., "$datasource")
+		// Only process template variables - other string values are not supported in V2 format
+		datasourceUID = dsStr
 	} else {
 		datasourceType = getDefaultDatasourceType(ctx, dsIndexProvider)
 	}
@@ -1532,6 +1536,10 @@ func buildAdhocVariable(ctx context.Context, varMap map[string]interface{}, comm
 			// If no UID and no type, use default
 			datasourceType = getDefaultDatasourceType(ctx, dsIndexProvider)
 		}
+	} else if dsStr, ok := datasource.(string); ok && isTemplateVariable(dsStr) {
+		// Handle datasource variable reference (e.g., "$datasource")
+		// Only process template variables - other string values are not supported in V2 format
+		datasourceUID = dsStr
 	} else {
 		datasourceType = getDefaultDatasourceType(ctx, dsIndexProvider)
 	}
@@ -1709,6 +1717,10 @@ func buildGroupByVariable(ctx context.Context, varMap map[string]interface{}, co
 
 		// Resolve Grafana datasource UID when type is "datasource" and UID is empty
 		datasourceUID = resolveGrafanaDatasourceUID(datasourceType, datasourceUID)
+	} else if dsStr, ok := datasource.(string); ok && isTemplateVariable(dsStr) {
+		// Handle datasource variable reference (e.g., "$datasource")
+		// Only process template variables - other string values are not supported in V2 format
+		datasourceUID = dsStr
 	} else {
 		datasourceType = getDefaultDatasourceType(ctx, dsIndexProvider)
 	}

apps/dashboard/pkg/migration/testdata/input/v15.mimir_rollout_debugging.json

@@ -654,7 +654,9 @@
           "text": "prod",
           "value": "prod"
         },
-        "datasource": "$datasource",
+        "datasource": {
+          "uid": "$datasource"
+        },
         "hide": 0,
         "includeAll": true,
         "label": "cluster",
@@ -677,7 +679,9 @@
           "text": "prod",
           "value": "prod"
         },
-        "datasource": "$datasource",
+        "datasource": {
+          "uid": "$datasource"
+        },
         "hide": 0,
         "includeAll": false,
         "label": "namespace",

apps/dashboard/pkg/migration/testdata/output/latest_version/v15.mimir_rollout_debugging.v42.json

@@ -737,7 +737,9 @@
           "text": "prod",
           "value": "prod"
         },
-        "datasource": "$datasource",
+        "datasource": {
+          "uid": "$datasource"
+        },
         "hide": 0,
         "includeAll": true,
         "label": "cluster",
@@ -758,7 +760,9 @@
           "text": "prod",
           "value": "prod"
         },
-        "datasource": "$datasource",
+        "datasource": {
+          "uid": "$datasource"
+        },
         "hide": 0,
         "includeAll": false,
         "label": "namespace",

apps/dashboard/pkg/migration/testdata/output/single_version/v15.mimir_rollout_debugging.v15.json

@@ -717,7 +717,9 @@
           "text": "prod",
           "value": "prod"
         },
-        "datasource": "$datasource",
+        "datasource": {
+          "uid": "$datasource"
+        },
         "hide": 0,
         "includeAll": true,
         "label": "cluster",
@@ -739,7 +741,9 @@
           "text": "prod",
           "value": "prod"
         },
-        "datasource": "$datasource",
+        "datasource": {
+          "uid": "$datasource"
+        },
         "hide": 0,
         "includeAll": false,
         "label": "namespace",