Fix concurrency bug in results view

In the results view, `setState` was used to set some state, and then
`loadResults` was called to set some other state. However, `setState`
is asynchronous, so the `this.state` in `loadResults` was not the state
that was set before the call.

This commit fixes it by combining the two `setState` calls into one. The
logic was hard to follow, so I'm not sure if this is the correct fix.
The `shouldKeepOldResultsWhileRendering` state seems to be unnecessary
now since everything is being done in `setState` call, but I'm not sure
about that.

Author: koesie10

extensions/ql-vscode/src/view/results/results.tsx

@@ -104,7 +104,6 @@ export class ResultsApp extends React.Component<
           queryPath: msg.queryPath,
         });
 
-        void this.loadResults();
         break;
       case "showInterpretedPage": {
         const tableName =
@@ -141,7 +140,6 @@ export class ResultsApp extends React.Component<
           queryName: msg.queryName,
           queryPath: msg.queryPath,
         });
-        void this.loadResults();
         break;
       }
       case "resultsUpdating":
@@ -164,76 +162,52 @@ export class ResultsApp extends React.Component<
 
   private updateStateWithNewResultsInfo(resultsInfo: ResultsInfo): void {
     this.setState((prevState) => {
-      const stateWithDisplayedResults = (
-        displayedResults: ResultsState,
-      ): ResultsViewState => ({
-        displayedResults,
-        isExpectingResultsUpdate: prevState.isExpectingResultsUpdate,
-        nextResultsInfo: resultsInfo,
-      });
-
-      if (!prevState.isExpectingResultsUpdate && resultsInfo === null) {
-        // No results to display
-        return stateWithDisplayedResults({
-          resultsInfo: null,
-          results: null,
-          errorMessage: "No results to display",
-        });
-      }
-      if (!resultsInfo || !resultsInfo.shouldKeepOldResultsWhileRendering) {
-        // Display loading message
-        return stateWithDisplayedResults({
-          resultsInfo: null,
-          results: null,
-          errorMessage: "Loading results…",
-        });
+      if (resultsInfo === null) {
+        if (prevState.isExpectingResultsUpdate) {
+          // Display loading message
+          return {
+            displayedResults: {
+              resultsInfo: null,
+              results: null,
+              errorMessage: "Loading results…",
+            },
+            isExpectingResultsUpdate: prevState.isExpectingResultsUpdate,
+            nextResultsInfo: resultsInfo,
+          };
+        } else {
+          // No results to display
+          return {
+            displayedResults: {
+              resultsInfo: null,
+              results: null,
+              errorMessage: "No results to display",
+            },
+            isExpectingResultsUpdate: prevState.isExpectingResultsUpdate,
+            nextResultsInfo: resultsInfo,
+          };
+        }
       }
-      return stateWithDisplayedResults(prevState.displayedResults);
-    });
-  }
-
-  private getResultSets(resultsInfo: ResultsInfo): readonly ResultSet[] {
-    const parsedResultSets = resultsInfo.parsedResultSets;
-    const resultSet = parsedResultSets.resultSet;
-    if (!resultSet.t) {
-      throw new Error(
-        'Missing result set type. Should be either "InterpretedResultSet" or "RawResultSet".',
-      );
-    }
-    return [resultSet];
-  }
 
-  private async loadResults(): Promise<void> {
-    const resultsInfo = this.state.nextResultsInfo;
-    if (resultsInfo === null) {
-      return;
-    }
+      let results: Results | null = null;
+      let statusText = "";
+      try {
+        const resultSets = this.getResultSets(resultsInfo);
+        results = {
+          resultSets,
+          database: resultsInfo.database,
+          sortStates: this.getSortStates(resultsInfo),
+        };
+      } catch (e) {
+        let errorMessage: string;
+        if (e instanceof Error) {
+          errorMessage = e.message;
+        } else {
+          errorMessage = "Unknown error";
+        }
 
-    let results: Results | null = null;
-    let statusText = "";
-    try {
-      const resultSets = this.getResultSets(resultsInfo);
-      results = {
-        resultSets,
-        database: resultsInfo.database,
-        sortStates: this.getSortStates(resultsInfo),
-      };
-    } catch (e) {
-      let errorMessage: string;
-      if (e instanceof Error) {
-        errorMessage = e.message;
-      } else {
-        errorMessage = "Unknown error";
+        statusText = `Error loading results: ${errorMessage}`;
       }
 
-      statusText = `Error loading results: ${errorMessage}`;
-    }
-
-    this.setState((prevState) => {
-      // Only set state if this results info is still current.
-      if (resultsInfo !== prevState.nextResultsInfo) {
-        return null;
-      }
       return {
         displayedResults: {
           resultsInfo,
@@ -246,6 +220,17 @@ export class ResultsApp extends React.Component<
     });
   }
 
+  private getResultSets(resultsInfo: ResultsInfo): readonly ResultSet[] {
+    const parsedResultSets = resultsInfo.parsedResultSets;
+    const resultSet = parsedResultSets.resultSet;
+    if (!resultSet.t) {
+      throw new Error(
+        'Missing result set type. Should be either "InterpretedResultSet" or "RawResultSet".',
+      );
+    }
+    return [resultSet];
+  }
+
   private getSortStates(
     resultsInfo: ResultsInfo,
   ): Map<string, RawResultsSortState> {