Web: cannot copy/cut/paste in webviews using keyboard

[bpasero]

Steps to Reproduce:

1. open https://vscode-web-test-playground.azurewebsites.net/?enter=true
2. open a markdown file
3. add <input> element
4. open preview
5. try to cut/copy/paste in the input field

=> 🐛 it does not work

I think this only reproduces in a built version of VSCode web, not running out of sources. Using bisect I found the commit range to be this: e7920dc...3bc3f95

My guess would be: 7e5937d

[mjbvz]

It seems to work for me when building from main with yarn web. Not sure what is different about that

In both cases however, we are not using our custom copy command. Here's what happens:

1. User presses cmd+c in webview
2. We intercept the keypresses in the webview and send them back to VS Code
3. We then handle the keypress in our keybindings service.
4. However on web, the copy command lacks an actual keybinding:

   vscode/src/vs/editor/contrib/clipboard/clipboard.ts

   Line 73 in f9d74e9

   // since browsers do that for us and it avoids security prompts

5. This means we never resolve a keybinding for cmd+c

@alexdima Any thoughts on how best to handle this case? Does the comment in clipboard.ts still apply?

[alexdima]

@mjbvz Yes, that is intentional. In browsers we don't want to ship with keybindings for cmd+c,cmd+v or cmd+x. We want browsers to execute their default action, we don't call preventDefault() and then browsers will invoke copy/paste/cut events without a security prompt. If we were to use a keybinding, we would have to go through clipboardService, which goes through the navigator clipboard API, which is not fully implemented in Firefox (so cmd+v will no longer work there at all) and which prompts in other browsers.

Long story short, my recommendation is that on the web you also do not capture cmd+c/cmd+v/cmd+x and allow the browser to generate copy/paste/cut events and add listeners for these events.

[mjbvz]

Thanks for the background @alexdima!

I previously added special logic that calls preventDefault for copy/paste: 7e5937d

We need this on desktop to prevent double pasting but I will remove the call to preventDefault on web

[bpasero]

Thanks, verified in https://vscode-web-test-playground.azurewebsites.net/?enter=true with todays build.