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0 pointsrubymamis2y ago0 comments

So they mention my exact concerns and addressed them, very cool. But their solution in practice doesn't look very different from what we can already achieve with git (apart from seeing your collaborator changes in real-time, which I'm not sure how substantial it is), or am I missing something?

At the end of the day, how will this look to the end user?

> a user may work in isolation on their own copy of a document for a while, without seeing other users’ real-time updates; sometime later, when they are ready to share their work, they can choose to merge it with their collaborators’ edits. Several such copies may exist side-by-side, and some might never be merged (e.g. if the user changed their mind about a set of edits).

Again, this sounds almost exactly like what we already achieve using git, so why do we need CRDTs for that?

0 comments

11 comments · 3 top-level

spencerflem2y ago· 4 in thread

The merging is automatic, for one

josephg2y ago

Yeah; and the merging is correct in all cases. You don't get spurious conflicts like you can with git.

Also the same system can work both in realtime and offline scenarios. And CRDTs can handle a lot more than just plain text editing.

That said, one thing git does that I like is that sometimes I want conflict markers to be added to my document when concurrent edits happen on the same line. CRDTs (and REGs like this) store strictly more information than git does, so theoretically it should be possible to make a CRDT which adds conflict markers too like git does. But as far as I know, nobody has built that yet! I really hope someone does, because it would be really neat.

I really want a git style version control system built on top of CRDTs with optional merge conflicts.

bmacho2y ago

> Yeah; and the merging is correct in all cases.

No, it's obviously not.

I'd say most of the time the merging is incorrect, that is, it is in contrast to both of the parties intention. Unlike git, which actually notifies them, Loro just silently modifies both changes into something nonsense/wrong.

2 more replies

WorldMaker2y ago

darcs [0] patch theory was a predecessor to OTs/CRDTs (and a predecessor to git as well; in some ways it is the "smart" to which git was named "dumb"). When it works and performs well it is still sometimes version control magic.

pijul [1] is an interesting experiment to watch, trying to keep the patch theory flag flying and also trying to bring in updates from OTs and CRDTs as it can.

[0] https://darcs.net

[1] https://pijul.org/

cubefox2y ago

What's more realistic: Git switching to some form of CRDT, or Git being superseded by a different system which is based on CRDTs?

wim2y ago· 2 in thread

Another issue which git won't solve is if you collaborate on text which has "structure". For example when merging indented (todo) lists as flat text, bullets might end up in the wrong place, e.g.

  [ ] Project
      [ ] Don't do this
          [ ] Task A

While offline, user #1 adds '[ ] Task B' and '[ ] rm -rf /' under "Don't Do This", while user #2 adds '[ ] Do This' under 'Project'. Obviously you don't want to merge this as:

   [ ] Project
      [ ] Don't do this
          [ ] A
      [ ] Do This
          [ ] B
          [ ] rm -rf /

We're working on an app [1] which needs to deal with this, but in general it also makes git less suitable for things like outliners or other collaborative text editors where people can work on lists, tables, and so on (structured data basically).

[1] https://thymer.com/

zachmu2y ago

Does the app store structured text in a structured way? You probably need to for this to work the way you want.

We are writing a version controlled database (Dolt) and we recently implemented automatic merging of the contents of JSON documents, seems related to what you're doing:

https://www.dolthub.com/blog/2024-01-16-announcing-json-merg...

samatman2y ago

I believe that handling merges like this correctly was a motive for designing pijul: https://pijul.org

See the item on the splash page about 'merge correctness'. Unfortunately I wasn't able to find the post detailing the behavior with a bit of searching.

codetrotter2y ago· 2 in thread

Plenty of people would rather spend their time doing their job at hand, than to fight with git and spend time having to learn git.

Suggesting that everyone should use git, is like the famous HN comment that dismissed Dropbox because “you could just use rsync”. IMO.

Like yeah, you could. But no, plenty of people will never want to do that.

rubymamisOP2y ago

Git is just the underlying mechanism. What you show to the user depends on your UX/UI. You don't need to show users the words "fork/merge" even. How about:

1. "Edit Joe's text"

2. "Ask Joe for a review"

3. "Do you want to add Alice's changes?"

jitl2y ago

For one thing, Git is abysmal at merging rich text formats that need balancing open/close annotation markers, like HTML <strong> and similar. With line/character oriented merge algorithms syntax errors from merge are inevitable. Once you start pulling that thread, like “ok can we clean up such mistakes automatically with a better merge algorithm that understands the content a bit more?” you’ll end up back here at CRDTs.

I’ve tried managing markdown docs in git a few times. Even with a team of senior+ engineer git experts it became a pain on frequently changing documents because conflicts were so common — if you wrap markdown at 80 characters, rewording a sentence is more likely to merge conflict than changing a variable in code since it may re-wrap several lines; and if you don’t wrap at all, any change in the paragraph will conflict on the entire paragraph.

2 more replies

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11 comments · 3 top-level

spencerflem2y ago· 4 in thread

The merging is automatic, for one

josephg2y ago

Yeah; and the merging is correct in all cases. You don't get spurious conflicts like you can with git.

Also the same system can work both in realtime and offline scenarios. And CRDTs can handle a lot more than just plain text editing.

I really want a git style version control system built on top of CRDTs with optional merge conflicts.

bmacho2y ago

> Yeah; and the merging is correct in all cases.

No, it's obviously not.

2 more replies

WorldMaker2y ago

pijul [1] is an interesting experiment to watch, trying to keep the patch theory flag flying and also trying to bring in updates from OTs and CRDTs as it can.

[0] https://darcs.net

[1] https://pijul.org/

cubefox2y ago

What's more realistic: Git switching to some form of CRDT, or Git being superseded by a different system which is based on CRDTs?

wim2y ago· 2 in thread

Another issue which git won't solve is if you collaborate on text which has "structure". For example when merging indented (todo) lists as flat text, bullets might end up in the wrong place, e.g.

  [ ] Project
      [ ] Don't do this
          [ ] Task A

While offline, user #1 adds '[ ] Task B' and '[ ] rm -rf /' under "Don't Do This", while user #2 adds '[ ] Do This' under 'Project'. Obviously you don't want to merge this as:

   [ ] Project
      [ ] Don't do this
          [ ] A
      [ ] Do This
          [ ] B
          [ ] rm -rf /

[1] https://thymer.com/

zachmu2y ago

Does the app store structured text in a structured way? You probably need to for this to work the way you want.

We are writing a version controlled database (Dolt) and we recently implemented automatic merging of the contents of JSON documents, seems related to what you're doing:

https://www.dolthub.com/blog/2024-01-16-announcing-json-merg...

samatman2y ago

I believe that handling merges like this correctly was a motive for designing pijul: https://pijul.org

See the item on the splash page about 'merge correctness'. Unfortunately I wasn't able to find the post detailing the behavior with a bit of searching.

codetrotter2y ago· 2 in thread

Plenty of people would rather spend their time doing their job at hand, than to fight with git and spend time having to learn git.

Suggesting that everyone should use git, is like the famous HN comment that dismissed Dropbox because “you could just use rsync”. IMO.

Like yeah, you could. But no, plenty of people will never want to do that.

rubymamisOP2y ago

Git is just the underlying mechanism. What you show to the user depends on your UX/UI. You don't need to show users the words "fork/merge" even. How about:

1. "Edit Joe's text"

2. "Ask Joe for a review"

3. "Do you want to add Alice's changes?"

jitl2y ago

2 more replies

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