Fix callback registration for cleanup

Author: mgsium

extensions/ql-vscode/src/extension.ts

@@ -494,28 +494,28 @@ async function activateWithInstalledDistribution(
     }
   }
 
+  const tmpDir = tmp.dirSync({ prefix: 'qhelp_', keep: false, unsafeCleanup: true });
+  ctx.subscriptions.push({ dispose: tmpDir.removeCallback });
+
   async function previewQueryHelp(
     selectedQuery: Uri
   ): Promise<void> {
-    const pathToQhelp = selectedQuery ? selectedQuery.fsPath : window.activeTextEditor!.document.uri.fsPath;
+    // selectedQuery is unpopulated when executing through the command palette
+    const pathToQhelp =  selectedQuery ? selectedQuery.fsPath : window.activeTextEditor!.document.uri.fsPath;
     if(pathToQhelp) {
       // Create temporary directory
-      return tmp.dir().then(async o => {
-        const relativePathToMd = path.basename(pathToQhelp, '.qhelp') + '.md';
-        const absolutePathToMd = path.join(o.path, relativePathToMd);
-        const uri = Uri.file(absolutePathToMd);
-        try {
-          await cliServer.generateQueryHelp(pathToQhelp , absolutePathToMd);
-          await commands.executeCommand('markdown.showPreviewToSide', uri);
-        } catch (err) {
-          const errorMessage =  err.message.includes('Generating qhelp in markdown') ? (
-            `Could not generate markdown from ${pathToQhelp}: Bad formatting in .qhelp file.`
-          ) : `Could not open a preview of the generated file (${absolutePathToMd}).`;
-          void helpers.showAndLogErrorMessage(errorMessage, { fullMessage: `${errorMessage}\n${err}` });
-        }
-        // Manual cleanup
-        void o.cleanup();
-      });
+      const relativePathToMd = path.basename(pathToQhelp, '.qhelp') + '.md';
+      const absolutePathToMd = path.join(tmpDir.name, relativePathToMd);
+      const uri = Uri.file(absolutePathToMd);
+      try {
+        await cliServer.generateQueryHelp(pathToQhelp , absolutePathToMd);
+        await commands.executeCommand('markdown.showPreviewToSide', uri);
+      } catch (err) {
+        const errorMessage =  err.message.includes('Generating qhelp in markdown') ? (
+          `Could not generate markdown from ${pathToQhelp}: Bad formatting in .qhelp file.`
+        ) : `Could not open a preview of the generated file (${absolutePathToMd}).`;
+        void helpers.showAndLogErrorMessage(errorMessage, { fullMessage: `${errorMessage}\n${err}` });
+      }
     }
 
   }