2. I don't know for a fact they're using OTs but given that you can edit from local / web pretty much simultaneously that's a good guess. Since you don't generally get actual simultaneous edits however (or you don't really have to optimize for this use case since a dev is either editing from the IDE or locally and "simultaneous usage" would generally be a product of network latency), one idea is you could use a tree-like CRDT that tracks divergences and have a UI element that allows nice manual conflict merges. Or you could invent an automated merging strategy, which may or may not be pretty hard.
2b. in re distributed building, https://www.bazel.io Google actually open sourced their build system but I'm not sure (I don't think) the distributed building aspect of it is included. Here's to hoping some headstrong engineer decides to write the open source version of it...that said it's probably not actually that important for most software
3. Cool. I'd love to see something like this from Gitlab! I think once people feel that they have control over the software and their code, it's all about usability, and if you nail that there will be plenty evangelizing the solution.
1. So the web idea syncs with the distributed filesystem before any commits are made. We plan to sync the filesystem of the application development container to both your local filesystem and to another container that runs the web idea. That would allow for the same effect, or not?
2. Pretty cool it has operational transformations (OT). We looked at this but it seemed that you either have to pick someone with OT or something that works well with code. We're not doing distributed building but we're considering distributed testing https://gitlab.com/gitlab-org/gitlab-ce/issues/19267
3. Yeah, this would work on your local GitLab instance, no third party needed.