Remove brackets from escaped value if just 1 value (#26995)

public/app/plugins/datasource/prometheus/datasource.test.ts

@@ -502,6 +502,10 @@ describe('PrometheusDatasource', () => {
       it('should return pipe separated values if the value is an array of strings', () => {
       it('should return pipe separated values if the value is an array of strings', () => {
         expect(ds.interpolateQueryExpr(['a|bc', 'de|f'], customVariable)).toEqual('(a\\\\|bc|de\\\\|f)');
         expect(ds.interpolateQueryExpr(['a|bc', 'de|f'], customVariable)).toEqual('(a\\\\|bc|de\\\\|f)');
       });
       });
+
+      it('should return 1 regex escaped value if there is just 1 value in an array of strings', () => {
+        expect(ds.interpolateQueryExpr(['looking*glass'], customVariable)).toEqual('looking\\\\*glass');
+      });
     });
     });
 
 
     describe('and variable allows all', () => {
     describe('and variable allows all', () => {
@@ -516,6 +520,10 @@ describe('PrometheusDatasource', () => {
       it('should return pipe separated values if the value is an array of strings', () => {
       it('should return pipe separated values if the value is an array of strings', () => {
         expect(ds.interpolateQueryExpr(['a|bc', 'de|f'], customVariable)).toEqual('(a\\\\|bc|de\\\\|f)');
         expect(ds.interpolateQueryExpr(['a|bc', 'de|f'], customVariable)).toEqual('(a\\\\|bc|de\\\\|f)');
       });
       });
+
+      it('should return 1 regex escaped value if there is just 1 value in an array of strings', () => {
+        expect(ds.interpolateQueryExpr(['looking*glass'], customVariable)).toEqual('looking\\\\*glass');
+      });
     });
     });
   });
   });
 
 

public/app/plugins/datasource/prometheus/datasource.ts

@@ -159,6 +159,11 @@ export class PrometheusDatasource extends DataSourceApi<PromQuery, PromOptions>
     }
     }
 
 
     const escapedValues = value.map(val => prometheusSpecialRegexEscape(val));
     const escapedValues = value.map(val => prometheusSpecialRegexEscape(val));
+
+    if (escapedValues.length === 1) {
+      return escapedValues[0];
+    }
+
     return '(' + escapedValues.join('|') + ')';
     return '(' + escapedValues.join('|') + ')';
   }
   }