Avoid running query when a user cancels when there are unsaved changes

Fixes #538

Adds a new menu item to cancel a query run when the query is unsaved.

Also, ensures that no warning message is sent to the console.

extensions/ql-vscode/CHANGELOG.md

@@ -3,7 +3,7 @@
 ## 1.3.3 - [UNRELEASED]
 
 - Fix display of raw results entities with label but no url.
-- Fix bug where sort order is forgotten when changing raw results page
+- Fix bug where sort order is forgotten when changing raw results page.
 
 ## 1.3.2 - 12 August 2020
 

extensions/ql-vscode/src/extension.ts

@@ -408,7 +408,11 @@ async function activateWithInstalledDistribution(
         await showResultsForCompletedQuery(item, WebviewReveal.NotForced);
       } catch (e) {
         if (e instanceof UserCancellationException) {
-          helpers.showAndLogWarningMessage(e.message);
+          if (e.silent) {
+            logger.log(e.message);
+          } else {
+            helpers.showAndLogWarningMessage(e.message);
+          }
         } else if (e instanceof Error) {
           helpers.showAndLogErrorMessage(e.message);
         } else {

extensions/ql-vscode/src/run-queries.ts

@@ -34,7 +34,15 @@ export const tmpDirDisposal = {
   }
 };
 
-export class UserCancellationException extends Error { }
+export class UserCancellationException extends Error {
+  /**
+   * @param message The error message
+   * @param silent If silent is true, then this exception will avoid showing a warning message to the user.
+   */
+  constructor(message?: string, public readonly silent = false) {
+    super(message);
+  }
+}
 
 /**
  * A collection of evaluation-time information about a query,
@@ -307,7 +315,11 @@ async function checkDbschemeCompatibility(
 
 /**
  * Prompts the user to save `document` if it has unsaved changes.
- * Returns true if we should save changes.
+ *
+ * @param document The document to save.
+ *
+ * @returns true if we should save changes and false if we should continue without saving changes.
+ * @throws UserCancellationException if we should abort whatever operation triggered this prompt
  */
 async function promptUserToSaveChanges(document: vscode.TextDocument): Promise<boolean> {
   if (document.isDirty) {
@@ -317,9 +329,14 @@ async function promptUserToSaveChanges(document: vscode.TextDocument): Promise<b
     else {
       const yesItem = { title: 'Yes', isCloseAffordance: false };
       const alwaysItem = { title: 'Always Save', isCloseAffordance: false };
-      const noItem = { title: 'No', isCloseAffordance: true };
+      const noItem = { title: 'No (run anyway)', isCloseAffordance: false };
+      const cancelItem = { title: 'Cancel', isCloseAffordance: true };
       const message = 'Query file has unsaved changes. Save now?';
-      const chosenItem = await vscode.window.showInformationMessage(message, { modal: true }, yesItem, alwaysItem, noItem);
+      const chosenItem = await vscode.window.showInformationMessage(
+        message,
+        { modal: true },
+        yesItem, alwaysItem, noItem, cancelItem
+      );
 
       if (chosenItem === alwaysItem) {
         await config.AUTOSAVE_SETTING.updateValue(true, vscode.ConfigurationTarget.Workspace);
@@ -329,6 +346,10 @@ async function promptUserToSaveChanges(document: vscode.TextDocument): Promise<b
       if (chosenItem === yesItem) {
         return true;
       }
+
+      if (chosenItem === cancelItem) {
+        throw new UserCancellationException('Query run cancelled.', true);
+      }
     }
   }
   return false;