Fix issue where BQ refused to generate "complex SQL" for a select (#2061

)

* Fix issue where BQ refused to generate "complex SQL" for a select

* Condition this behavior on ##! unsafe_complex_select_query compiler flag

* Add a TODO on the test

packages/malloy/src/lang/test/expressions.spec.ts

@@ -334,6 +334,18 @@ describe('expressions', () => {
       errorMessage('Filtered expression requires an aggregate computation')
     );
   });
+  test('can use calculate with partition by in select', () => {
+    expect(markSource`
+    ##! experimental { partition_by function_order_by }
+    run: a -> {
+      select: ai, astr
+      calculate: prev is lag(ai) {
+        partition_by: astr
+        order_by: ai asc
+      }
+      order_by: ai asc, astr asc
+    }`).toTranslate();
+  });
 
   describe('expr props', () => {
     test('aggregate order by not allowed without experiments enabled', () => {

packages/malloy/src/model/malloy_query.ts

@@ -131,6 +131,7 @@ import {
   shouldMaterialize,
 } from './materialization/utils';
 import {EventStream} from '../runtime_types';
+import {Tag} from '../tags';
 
 interface TurtleDefPlus extends TurtleDef, Filtered {}
 
@@ -3411,9 +3412,13 @@ class QueryQuery extends QueryField {
     };
     this.generateStage0Fields(this.rootResult, f, stageWriter);
 
-    if (this.firstSegment.type === 'project') {
+    if (
+      this.firstSegment.type === 'project' &&
+      !this.parent.modelCompilerFlags().has('unsafe_complex_select_query')
+    ) {
       throw new Error('PROJECT cannot be used on queries with turtles');
     }
+
     const groupBy = 'GROUP BY ' + f.dimensionIndexes.join(',') + '\n';
 
     from += this.parent.dialect.sqlGroupSetTable(this.maxGroupSet) + '\n';
@@ -4312,6 +4317,16 @@ class QueryStruct {
     this.addFieldsFromFieldList(structDef.fields);
   }
 
+  private _modelTag: Tag | undefined = undefined;
+  modelCompilerFlags(): Tag {
+    if (this._modelTag === undefined) {
+      const annotation = this.structDef.modelAnnotation;
+      const {tag} = Tag.annotationToTag(annotation, {prefix: /^##!\s*/});
+      this._modelTag = tag;
+    }
+    return this._modelTag;
+  }
+
   protected findFirstDialect(): string {
     if (isSourceDef(this.structDef)) {
       return this.structDef.dialect;

test/src/databases/all/functions.spec.ts

@@ -1741,6 +1741,42 @@ describe.each(runtimes.runtimeList)('%s', (databaseName, runtime) => {
         {name: 'UNITED AIR LINES INC', r: 1},
       ]);
     });
+
+    // TODO remove the need for the `##! unsafe_complex_select_query` compiler flag
+    it('can be used in a select', async () => {
+      await expect(`
+        ##! experimental { function_order_by partition_by }
+        ##! unsafe_complex_select_query
+        run: state_facts -> {
+          select: state, births, popular_name
+          calculate: prev_births_by_name is lag(births) {
+            partition_by: popular_name
+            order_by: births desc
+          }
+          order_by: births desc
+          limit: 3
+        }
+      `).malloyResultMatches(expressionModel, [
+        {
+          state: 'CA',
+          births: 28810563,
+          popular_name: 'Isabella',
+          prev_births_by_name: null,
+        },
+        {
+          state: 'NY',
+          births: 23694136,
+          popular_name: 'Isabella',
+          prev_births_by_name: 28810563,
+        },
+        {
+          state: 'TX',
+          births: 21467359,
+          popular_name: 'Isabella',
+          prev_births_by_name: 23694136,
+        },
+      ]);
+    });
   });
 });