Add cml-send-comment --update

[0x2b3bfa0]

Running cml-send-comment with the newly introduced --update flag will update the last CML comment instead of creating a new one. Comment authorship is determined by checking an invisible watermark [sic] added by CML to every machine-made comment. Watermarks are just void images appended with Markdown at the end of comments.

Supported platforms

• GitHub
• GitLab¹
• Bitbucket²

---

¹ Blocked by gitlab-org/gitlab#333000; there is no known workaround.
² Requires user interaction for the first time, as per #581 (comment).

[casperdcl]

Given https://github.com/iterative/cml/wiki/Backend-Supported-Features we could still merge anyway

[0x2b3bfa0]

Pull Request Commit Links app must be installed first before using this API; installation automatically occurs when 'Go to pull request' is clicked from the web interface for a commit's details. (Clinical definition of insanity)

⚠️ Bitbucket support won't be fully functional until users (cough) install the Pull Request Commit Links application. In the worst case scenario, commit comments will be created and pull request comments won't.

[0x2b3bfa0]

Hopefully I won't have to think about John Woods' quote for a long, long time. 😈

[DavidGOrtega]

⚠️ Bitbucket support won't be fully functional until users (cough) install the Pull Request Commit Links application. In the worst case scenario, commit comments will be created and pull request comments won't.

I wonder if we should unsupport Bitbucket. Sounds very flaky and confusing

[0x2b3bfa0]

What if we convert the disabled API warning into a fatal error and put it first? This way, users will need to enable the API before using cml-send-comment on Bitbucket. Nevertheless, it's as confusing as you think and, even with good documentation, may be challenging for some users.

[DavidGOrtega]

...it's as confusing as you think and, even with good documentation, may be challenging for some users.

Let's remove it then for Bitbucket.

[casperdcl]

😱 I wouldn't remove BB functionality just because of a confusing one-click mechanism. Helpful error message (possibly throw/non-zero exit) plz.

[DavidGOrtega]

😱 I wouldn't remove BB functionality just because of a confusing one-click mechanism. Helpful error message (possibly throw/non-zero exit) plz.

Ok but also has to be well documented, the last thing I want is we having to answer questions about why is not working in BB

[0x2b3bfa0]

@DavidGOrtega & @casperdcl, do you like this fix à la #563ème?

[0x2b3bfa0]

I miss #538 with granular tests and ephemeral repositories. 🐲 Having to manually delete comments before running automated tests is... far from ideal.

FAIL src/drivers/bitbucket_cloud.test.js
[Forbidden] By default, you can't create more than 1000 comments per pull request. Contact support to update this limit.

[DavidGOrtega]

I miss #538 with granular tests and ephemeral repositories. 🐲 Having to manually delete comments before running automated tests is... far from ideal.

FAIL src/drivers/bitbucket_cloud.test.js
[Forbidden] By default, you can't create more than 1000 comments per pull request. Contact support to update this

This is weird, we fixed this already. As far as I remmber