Format button breaks undo

[broady]

To reproduce:

1. Go to http://www.gopherjs.org/playground
2. De-indent the three lines in main
3. Press "Format"
4. Ctrl-Z repeatedly

What I see:

Corrupted text.

What I want to see:

Ctrl+Z undoes formatting, then continues to undo previous operations.

/cc @francesc

[dmitshur]

Thanks for reporting this with clear reproduce steps.

I can reproduce this both on http://www.gopherjs.org/playground/ AND on https://play.golang.org/ in latest stable version of Chrome.

The code for applying formatting is very straightforward, it simply overwrites the entire content with the new formatted code.</p> <p>Given that it's also a bug on the official Go Playground, I suspect it's a browser thing. Whatever the fix is there is likely to be applicable here as well.</p> <hr /> <p>Okay, I just tried the same steps in Firefox, and the issue does not occur there. It undoes the formatting and edits before it without issues.</p> <p>So, given it's a browser bug (that's likely to be fixed in the future) and not a bug specific to GopherJS Playground, it should be reasonable to close this, right?</p> <p>It's probably also a good idea to make a small repro case and submit a bug report to Chrome project, if it's not already a known/reported bug.</p> </div> </div> <div class="comment"> <div class="user"> <a rel="noreferrer nofollow" target="_blank" href="https://github.com/dmitshur"><img src="https://avatars.githubusercontent.com/u/1924134?v=4" />dmitshur</a> commented <strong> 8 years ago</strong> </div> <div class="markdown-body"> <p>Tested in latest stable Safari (Version 9.1.2 (11601.7.7)) and the bug happens there too (on both playgrounds). So I suspect it might be a long-standing WebKit issue (and probably already reported, but not easy to fix).</p> </div> </div> <div class="page-bar-simple"> </div> <div class="footer"> <ul class="body"> <li>© <script> document.write(new Date().getFullYear()) </script> Githubissues.</li> <li>Githubissues is a development platform for aggregating issues.</li> </ul> </div> <script src="https://cdn.jsdelivr.net/npm/jquery@3.5.1/dist/jquery.min.js"></script> <script src="/githubissues/assets/js.js"></script> <script src="/githubissues/assets/markdown.js"></script> <script src="https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.4.0/build/highlight.min.js"></script> <script src="https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.4.0/build/languages/go.min.js"></script> <script> hljs.highlightAll(); </script> </body> </html>