Fix freeze on pad deletion

[Chocobozzz]

Fix freeze on pad deletion (if it has many revisions)

Needs ether/ueberDB#118 first (because of https://github.com/Pita/ueberDB/pull/118/files#diff-0a774d4a9cc6e6d690c76811449906c1R214)

[muxator]

Now that we implemented #3540 this patch should be adapted to async/await style.

[raybellis]

I think this needs to be tested with the async version to see whether it still even causes any freezes.

The new code doesn't explicitly wait for any of the db.remove() operations to complete before returning, they're all just sent to the backend database engine asynchronously.

[Chocobozzz]

@raybellis yes we wait: https://github.com/ether/etherpad-lite/pull/3562/files#diff-89eec47c9f1563e5a2c346b4a649a7f0R680

[raybellis]

Sorry, I was talking about the new async code in the develop branch, not the new code in your patch.

[muxator]

@Chocobozzz, any chance you are able to forward port this fix to the current develop? It would be nice if it gets included in 1.8.0.

[Chocobozzz]

Sorry for the late. Can I add bluebird as dependency to use the map function?

[Chocobozzz]

ping @muxator

[muxator]

Hi, @Chocobozzz, sorry for being late.

I just tested installing it and bluebird has no dependencies and is not too big (~700 KB).
May there any way of accomplishing what you need just using the standard library?
If not, please go on adding it.

~/test$ npm install bluebird
+ bluebird@3.7.2
added 1 package from 1 contributor in 0.247s

~/test/node_modules$ du -sch bluebird/
712K    bluebird/
712K    total

[raybellis]

IMHO, adding Bluebird is excessive just to get access to a Promise .map function. In the new async code there are plenty of instances where I've used trivial "native" code to implement similar functionality.

[Chocobozzz]

IMHO, adding Bluebird is excessive just to get access to a Promise .map function. In the new async code there are plenty of instances where I've used trivial "native" code to implement similar functionality.

Where do you use a map with a concurrency limit?

[raybellis]

Fair enough, although you didn't call that out as a specific requirement in your suggestion.

[muxator]

Before merging this PR, we have to remember that we depend on a new release of ueberdb (that incorporates ether/ueberDB#118), or we have to go on with #3675.

[Chocobozzz]

I created a custom function instead of adding bluebird and updated the PR

[JohnMcLear]

FWIW the UeberDB patch got merged ages ago and it's released on npm so should be good from UeberDB side. cc @muxator

[muxator]

This will be pulled in as soon as #3734 is integrated.

[muxator]

We can go on with this PR, since ueberDB was updated via #3734.

But I see there are conflicts.

If the conflicts are trivial I can take care of it. If they end up being more that pure dumb text manipulation I will need support from @Chocobozzz.

[muxator]

@Chocobozzz: before merging, I would like - please - that you insert a short note explaining the purpose of src/node/utils/promises.js for the posterity.

I think I got the reason for the conflicts: your develop branch still points to 4944945. There are no particular conflicts otherwise, is a well contained change. I can take care of that if updating your repo is complicated.

Just write me a bit of documentation. 😄

[Chocobozzz]

Done 👍

[muxator]

This was long overdue.

Merged & queued for 1.8.3, thanks.