Add 'Discard All and Pull' button (#1020)

* Add discard and pull menu item

* Apply suggestions from code review

Co-authored-by: Frédéric Collonval <fcollonval@gmail.com>

* Add missing entry menu in settings description

* Add discard fallback to pull operation

* Remove unused command ids

* Apply suggestions from code review

Co-authored-by: Frédéric Collonval <fcollonval@gmail.com>

* Apply suggestions from code review

* Rename `discard` to `force` to align with `push`

* Hide toast if action cancelled by user

Co-authored-by: Frédéric Collonval <fcollonval@gmail.com>
Co-authored-by: Frédéric Collonval <fcollonval@users.noreply.github.com>

Author: navn-r

schema/plugin.json

@@ -98,9 +98,17 @@
           {
             "command": "git:push"
           },
+          {
+            "command": "git:push",
+            "args": { "force": true }
+          },
           {
             "command": "git:pull"
           },
+          {
+            "command": "git:pull",
+            "args": { "force": true }
+          },
           {
             "command": "git:add-remote"
           },

src/commandsAndMenu.tsx

@@ -46,6 +46,7 @@ import {
   Level
 } from './tokens';
 import { GitCredentialsForm } from './widgets/CredentialsBox';
+import { discardAllChanges } from './widgets/discardAllChanges';
 import { GitCloneForm } from './widgets/GitCloneForm';
 
 interface IGitCloneArgs {
@@ -389,15 +390,26 @@ export function addCommands(
 
   /** Add git pull command */
   commands.addCommand(CommandIDs.gitPull, {
-    label: trans.__('Pull from Remote'),
-    caption: trans.__('Pull latest code from remote repository'),
+    label: args =>
+      args.force
+        ? trans.__('Pull from Remote (Force)')
+        : trans.__('Pull from Remote'),
+    caption: args =>
+      args.force
+        ? trans.__(
+            'Discard all current changes and pull from remote repository'
+          )
+        : trans.__('Pull latest code from remote repository'),
     isEnabled: () => gitModel.pathRepository !== null,
-    execute: async () => {
-      logger.log({
-        level: Level.RUNNING,
-        message: trans.__('Pulling…')
-      });
+    execute: async args => {
       try {
+        if (args.force) {
+          await discardAllChanges(gitModel, trans, args.fallback as boolean);
+        }
+        logger.log({
+          level: Level.RUNNING,
+          message: trans.__('Pulling…')
+        });
         const details = await Private.showGitOperationDialog(
           gitModel,
           Operation.Pull,
@@ -413,11 +425,37 @@ export function addCommands(
           'Encountered an error when pulling changes. Error: ',
           error
         );
-        logger.log({
-          message: trans.__('Failed to pull'),
-          level: Level.ERROR,
-          error: error as Error
-        });
+
+        const errorMsg =
+          typeof error === 'string' ? error : (error as Error).message;
+
+        // Discard changes then retry pull
+        if (
+          errorMsg
+            .toLowerCase()
+            .includes(
+              'your local changes to the following files would be overwritten by merge'
+            )
+        ) {
+          await commands.execute(CommandIDs.gitPull, {
+            force: true,
+            fallback: true
+          });
+        } else {
+          if ((error as any).cancelled) {
+            // Empty message to hide alert
+            logger.log({
+              message: '',
+              level: Level.INFO
+            });
+          } else {
+            logger.log({
+              message: trans.__('Failed to pull'),
+              level: Level.ERROR,
+              error
+            });
+          }
+        }
       }
     }
   });
@@ -1155,10 +1193,13 @@ export function createGitMenu(
     CommandIDs.gitAddRemote,
     CommandIDs.gitTerminalCommand
   ].forEach(command => {
+    menu.addItem({ command });
     if (command === CommandIDs.gitPush) {
       menu.addItem({ command, args: { force: true } });
     }
-    menu.addItem({ command });
+    if (command === CommandIDs.gitPull) {
+      menu.addItem({ command, args: { force: true } });
+    }
   });
 
   menu.addItem({ type: 'separator' });

src/components/FileList.tsx

@@ -21,6 +21,7 @@ import { ContextCommandIDs, CommandIDs, Git } from '../tokens';
 import { ActionButton } from './ActionButton';
 import { FileItem } from './FileItem';
 import { GitStage } from './GitStage';
+import { discardAllChanges } from '../widgets/discardAllChanges';
 
 export interface IFileListState {
   selectedFile: Git.IStatusFile | null;
@@ -189,7 +190,7 @@ export class FileList extends React.Component<IFileListProps, IFileListState> {
     const result = await showDialog({
       title: this.props.trans.__('Discard all changes'),
       body: this.props.trans.__(
-        'Are you sure you want to permanently discard changes to all files? This action cannot be undone.'
+        'Are you sure you want to permanently discard changes to all unstaged files? This action cannot be undone.'
       ),
       buttons: [
         Dialog.cancelButton({ label: this.props.trans.__('Cancel') }),
@@ -211,26 +212,7 @@ export class FileList extends React.Component<IFileListProps, IFileListState> {
   /** Discard changes in all unstaged and staged files */
   discardAllChanges = async (event: React.MouseEvent): Promise<void> => {
     event.stopPropagation();
-    const result = await showDialog({
-      title: this.props.trans.__('Discard all changes'),
-      body: this.props.trans.__(
-        'Are you sure you want to permanently discard changes to all files? This action cannot be undone.'
-      ),
-      buttons: [
-        Dialog.cancelButton({ label: this.props.trans.__('Cancel') }),
-        Dialog.warnButton({ label: this.props.trans.__('Discard') })
-      ]
-    });
-    if (result.button.accept) {
-      try {
-        await this.props.model.resetToCommit();
-      } catch (reason) {
-        showErrorMessage(
-          this.props.trans.__('Discard all changes failed.'),
-          reason
-        );
-      }
-    }
+    await discardAllChanges(this.props.model, this.props.trans);
   };
 
   /** Add a specific unstaged file */

src/tokens.ts

@@ -1074,7 +1074,6 @@ export enum CommandIDs {
   gitMerge = 'git:merge',
   gitOpenGitignore = 'git:open-gitignore',
   gitPush = 'git:push',
-  gitForcePush = 'git:force-push',
   gitPull = 'git:pull',
   gitSubmitCommand = 'git:submit-commit',
   gitShowDiff = 'git:show-diff'

src/widgets/discardAllChanges.ts

@@ -0,0 +1,43 @@
+import { showDialog, Dialog, showErrorMessage } from '@jupyterlab/apputils';
+import { TranslationBundle } from '@jupyterlab/translation';
+import { IGitExtension } from '../tokens';
+
+/**
+ * Discard changes in all unstaged and staged files
+ *
+ * @param isFallback If dialog is called when the classical pull operation fails
+ */
+export async function discardAllChanges(
+  model: IGitExtension,
+  trans: TranslationBundle,
+  isFallback?: boolean
+): Promise<void> {
+  const result = await showDialog({
+    title: trans.__('Discard all changes'),
+    body: isFallback
+      ? trans.__(
+          'Your current changes forbid pulling the latest changes. Do you want to permanently discard those changes? This action cannot be undone.'
+        )
+      : trans.__(
+          'Are you sure you want to permanently discard changes to all files? This action cannot be undone.'
+        ),
+    buttons: [
+      Dialog.cancelButton({ label: trans.__('Cancel') }),
+      Dialog.warnButton({ label: trans.__('Discard') })
+    ]
+  });
+
+  if (result.button.accept) {
+    try {
+      return model.resetToCommit('HEAD');
+    } catch (reason) {
+      showErrorMessage(trans.__('Discard all changes failed.'), reason);
+      return Promise.reject(reason);
+    }
+  }
+
+  return Promise.reject({
+    cancelled: true,
+    message: 'The user refused to discard all changes'
+  });
+}