Reading some feedback on meta.stackexchange.com I got the impression that this community feels quite tense about the upcoming CommonMark migration. I feel that some extra levels of transparency shared right here might make your lives a little easier and help alleviate some of the tension, so let me try to address some of the concerns and give you a more detailed schedule so none of you needs to feel trapped waiting for the migration to kick off at any time today.
- 12:06 UTC: kicking off the migration for tex.meta.se. CommonMark is enabled, posts are migrating
- 12:11 UTC: posts on tex.meta.se are migrated. No problems detected.
- 12:16 UTC: kicking off the migration for tex.se. CommonMark is enabled, posts are migrating
- 12:48 UTC: migration for meta and the main sites are done. CommonMark is enabled for all new posts and incoming edits.
Schedule for tex.meta.se and tex.se
I'm in no rush to get this migration started right away. If you want to be around during the migration to double-check that nothing broke that's great.
I aim to run the migration around 12pm UTC.
Things might shift a bit since my days are sometimes unpredictable, but that's roughly what I'm aiming for. I'll update this post once I start the migration and once the migration has finished.
The migration run itself should not take longer than 15 minutes.
Will this break any posts?
I don't know the history of the issues during the last migration first hand but did my best to understand what happened based on what you shared on meta.se. I understand that this has been painful to find and fix.
To reiterate what's going to happen during the migration:
- we take the Markdown source of each post on a site
- we apply some fixes to make that Markdown CommonMark compliant
- we render the new, CommonMark compliant markdown source with our new CommonMark renderer to produce HTML output
- we take that HTML and compare it to the current HTML version of that post (the HTML that has been rendered with the old Markdown renderer)
- if we figure out that there's a difference between the old and the new HTML output, we will leave the post untouched and continue serving the old HTML version until someone goes in and edits the post in question
- if we think there's no difference between new and old HTML, we will store the new, tweaked markdown source as a new revision on the post. The new HTML will be served when viewing the post moving forward
This mechanism itself is quite defensive and will prevent breaking a large scale of posts at once. If a post looks differently after the migration, we won't touch it.
Using revisions allows us to undo things should we detect that something broke. We have a mechanism in place that can roll back all changes that have been done as part of this migration. I hope we never have to use it, but it's there just in case.
These precautions might alleviate some of the concerns we have and I personally put a lot of trust into this process. I tried to do my due diligence and tested scenarios specifically related to the last round of issues that you mentioned.
I also know that I'm fallible and things can go wrong for unforeseen reasons. Please don't take my word that things are going to be just fine. I appreciate feedback and double-checking that we didn't break anything - you all know this site better than I do.
I hope with this more detailed schedule and explanation we can make this experience as smooth as possible. I'll keep this post updated so that you know when you can start hunting for bugs!