API Calls with Undo Leave Cursor in Wrong Position

[jpotterm]

Environment

• VSCode Version: 1.19.3
• OS Version: macOS 10.13.3
• Does this issue occur when all extensions are disabled?: Yes

Steps to Reproduce

Create an extension with the following activate function:

export async function activate(context: vscode.ExtensionContext): Promise<void> {
    const editor = vscode.window.activeTextEditor;

    if (!editor) return;

    await editor.edit(function(editBuilder) {
        editBuilder.delete(
            new vscode.Range(
                new vscode.Position(0, 0),
                new vscode.Position(0, 2),
            )
        );
    });

    await vscode.commands.executeCommand('undo');

    await editor.edit(function(editBuilder) {
        editBuilder.delete(
            new vscode.Range(
                new vscode.Position(0, 0),
                new vscode.Position(0, 1),
            )
        );
    });
}

And run it on a text file containing:

|ab

Where | denotes the cursor position. I would expect the result to be |b but the cursor ends up in the wrong position: b|.

Here are the expected results for each of the three steps that the code does:

1. The first edit should and does give |
2. Then the undo should and does give |ab
3. Then the second edit should give |b, but does give b|

Another peculiarity that may be related is that if I undo after running that code I get a TextEditorSelectionChangeEvent with kind: keyboard even though I haven't moved the cursor. That doesn't happen with similar code that leaves the cursor in the expected position.