Prefer #select result set over other result sets

For `@kind problem` queries, it seems like the BQRS contains four
result sets: `edges`, `nodes`, `subpaths`, and `#select`. The user is
probably interested in the results of `#select` since that contains the
direct result of the query. This changes the extraction of raw (BQRS)
results to always prefer `#select` over any other result set. If it
can't find a result set named `#select`, it will fall back to the first
result set in the BQRS like before.

Author: koesie10

extensions/ql-vscode/src/variant-analysis/bqrs-processing.ts

@@ -3,6 +3,7 @@ import { Logger } from "../common";
 import { transformBqrsResultSet } from "../pure/bqrs-cli-types";
 import { AnalysisRawResults } from "./shared/analysis-result";
 import { MAX_RAW_RESULTS } from "./shared/result-limits";
+import { SELECT_TABLE_NAME } from "../pure/interface-types";
 
 export async function extractRawResults(
   cliServer: CodeQLCliServer,
@@ -19,11 +20,15 @@ export async function extractRawResults(
   }
   if (resultSets.length > 1) {
     void logger.log(
-      "Multiple result sets found in results file. Only the first one will be used.",
+      "Multiple result sets found in results file. Only one will be used.",
     );
   }
 
-  const schema = resultSets[0];
+  // Always prefer #select over any other result set. #select is usually the result the user
+  // wants to see since it contains the outer #select.
+  const schema =
+    resultSets.find((resultSet) => resultSet.name === SELECT_TABLE_NAME) ??
+    resultSets[0];
 
   const chunk = await cliServer.bqrsDecode(filePath, schema.name, {
     pageSize: MAX_RAW_RESULTS,