Loki Query Builder: Throw warning in query builder when order of operations is ambiguous (#75198)

* flag vector aggregations containing metric expressions (i.e.`(...)`) containing binary operation expressions with ambiguous error in the UI when switching between code and visual query builders.

public/app/plugins/datasource/loki/querybuilder/parsing.test.ts

@@ -235,6 +235,22 @@ describe('buildVisualQueryFromString', () => {
     );
   });
 
+  it('returns error when parsing ambiguous query', () => {
+    //becomes topk(5, count_over_time({app="aggregator"} [1m])) / count_over_time({cluster="dev-eu-west-2"} [1m])
+    const context = buildVisualQueryFromString(
+      'topk(5,count_over_time({app="aggregator"}[1m])/count_over_time({cluster="dev-eu-west-2"}[1m]))'
+    );
+    expect(context).toMatchObject({
+      errors: [
+        {
+          from: 7,
+          text: 'Query parsing is ambiguous.',
+          to: 93,
+        },
+      ],
+    });
+  });
+
   it('parses query with matcher label filter', () => {
     expect(buildVisualQueryFromString('{app="frontend"} | bar="baz"')).toEqual(
       noErrors({
@@ -535,7 +551,8 @@ describe('buildVisualQueryFromString', () => {
   });
 
   it('parses metrics query with function and aggregation with grouping at the end', () => {
-    expect(buildVisualQueryFromString('sum(rate({app="frontend"} | json [5m])) without(job,name)')).toEqual(
+    const expression = 'sum(rate({app="frontend"} | json [5m])) without(job,name)';
+    expect(buildVisualQueryFromString(expression)).toEqual(
       noErrors({
         labels: [
           {
@@ -667,7 +684,9 @@ describe('buildVisualQueryFromString', () => {
   });
 
   it('parses query with multiple label format', () => {
-    expect(buildVisualQueryFromString('{app="frontend"} | label_format renameTo=original, bar=baz')).toEqual(
+    // Converted to {app="frontend"} | label_format renameTo=original | label_format bar=baz by visual query builder
+    const expression = '{app="frontend"} | label_format renameTo=original, bar=baz';
+    expect(buildVisualQueryFromString(expression)).toEqual(
       noErrors({
         labels: [
           {
@@ -715,9 +734,10 @@ describe('buildVisualQueryFromString', () => {
   });
 
   it('parses chained binary query', () => {
-    expect(
+    const expression = 'rate({project="bar"}[5m]) * 2 / rate({project="foo"}[5m]) + rate({app="test"}[1m])';
-      buildVisualQueryFromString('rate({project="bar"}[5m]) * 2 / rate({project="foo"}[5m]) + rate({app="test"}[1m])')
+    // is converted to (rate({project="bar"} [5m]) * 2) / (rate({project="foo"} [5m]) + rate({app="test"} [1m])) by visual query builder
-    ).toEqual(
+    // Note the extra parenthesis around the first binary operation expression: (rate({project="bar"} [5m]) * 2)
+    expect(buildVisualQueryFromString(expression)).toEqual(
       noErrors({
         labels: [{ op: '=', value: 'bar', label: 'project' }],
         operations: [
@@ -777,7 +797,9 @@ describe('buildVisualQueryFromString', () => {
   });
 
   it('parses a regexp with no param', () => {
-    expect(buildVisualQueryFromString('{app="frontend"} | regexp ')).toEqual(
+    const expression = '{app="frontend"} | regexp ';
+    // Converted to {app="frontend"} | regexp `` by visual query builder
+    expect(buildVisualQueryFromString(expression)).toEqual(
       noErrors({
         labels: [
           {

public/app/plugins/datasource/loki/querybuilder/parsing.ts

@@ -541,6 +541,15 @@ function handleVectorAggregation(expr: string, node: SyntaxNode, context: Contex
   const op: QueryBuilderOperation = { id: funcName, params };
 
   if (metricExpr) {
+    // A vector aggregation expression with a child of metric expression with a child of binary expression is ambiguous after being parsed into a visual query
+    if (metricExpr.firstChild?.type.id === BinOpExpr) {
+      context.errors.push({
+        text: 'Query parsing is ambiguous.',
+        from: metricExpr.firstChild.from,
+        to: metricExpr.firstChild?.to,
+      });
+    }
+
     handleExpression(expr, metricExpr, context);
   }