Prometheus: Fix quote stripping in parser (#87675)

* Prometheus: Fix quote stripping in parser

Currently only double quotes are stripped from the end, while single quotes are left. Moreover, double quotes are stripped even when part of the value

* Prometheus: Double escape the string, apply linting fixes for files that I touched

packages/grafana-prometheus/src/querybuilder/parsing.test.ts

@@ -746,6 +746,43 @@ describe('buildVisualQueryFromString', () => {
       },
     });
   });
+
+  it('strips enclosing quotes', () => {
+    expect(buildVisualQueryFromString("counters_logins{app='frontend', host=`localhost`}")).toEqual(
+      noErrors({
+        metric: 'counters_logins',
+        labels: [
+          {
+            op: '=',
+            value: 'frontend',
+            label: 'app',
+          },
+          {
+            op: '=',
+            value: 'localhost',
+            label: 'host',
+          },
+        ],
+        operations: [],
+      })
+    );
+  });
+
+  it('leaves escaped quotes inside string', () => {
+    expect(buildVisualQueryFromString('counters_logins{app="fron\\"\\"tend"}')).toEqual(
+      noErrors({
+        metric: 'counters_logins',
+        labels: [
+          {
+            op: '=',
+            value: 'fron\\"\\"tend',
+            label: 'app',
+          },
+        ],
+        operations: [],
+      })
+    );
+  });
 });
 
 function noErrors(query: PromVisualQuery) {

packages/grafana-prometheus/src/querybuilder/parsing.ts

@@ -205,7 +205,7 @@ function isIntervalVariableError(node: SyntaxNode) {
 function getLabel(expr: string, node: SyntaxNode): QueryBuilderLabelFilter {
   const label = getString(expr, node.getChild(LabelName));
   const op = getString(expr, node.getChild(MatchOp));
-  const value = getString(expr, node.getChild(StringLiteral)).replace(/"/g, '');
+  const value = getString(expr, node.getChild(StringLiteral)).replace(/^["'`]|["'`]$/g, '');
   return {
     label,
     op,