🥅 Goals
Splitting up the GUI (and splitting out modules in general) has been brought up often in recent years. Now that the GUI is primarily connected through (internal) interfaces with the node, it seems an appropriate time to revive this discussion.
Before looking for solutions, we should define a set of goals that we want to achieve. I will start with some ideas to get started and I hope that others will chime in to share and prioritize their goals.
Separate issue and patch management
It is currently not possible to subscribe to only a subset of modules in Bitcoin Core, or exclude modules from issue and patch notifications. While it is possible to reactively mute conversations in the stream of all ongoing discussions, there is no way to proactively achieve this. Moreover, the list of open issues and pull request will always include GUI related ones by default. Only with filters it is possible to hide them.
More focused review and interests
Long term goals of the GUI are partially unclear #17395 . Bitcoin Core developers are generally fluent on the command line. Thus, they might not be interested or motivated to review improvements to the GUI, which might not affect their workflow on the command line at all. Splitting up the GUI will hopefully attract similar minded people to a project whose primary goal is to build and improve the GUI.
Maintain high quality assurance
The quality of the GUI (and even more importantly Bitcoin Core in general) must not degrade. This means that code review itself is not negatively affected by splitting the GUI, but also the integration of the GUI into the rest of Bitcoin Core. One issue could arise when arbitrary version-combinations are allowed. We are struggling hard to test against all supported versions of Boost. Making the GUI version another dimension is going to make testing impossible.
The GUI is Bitcoin Core
When a user downloads Bitcoin Core from our website (or another package manager) they expect the GUI to be included. This should not change (at least not as a result of splitting up the GUI into another project).
Similarly, when building Bitcoin Core, the gui should still be built when --with-gui
is specified.
🌳 Proposed solution: Monotree
TLDR. Everything stays the same, the development process for the GUI changes slightly.
Long version:
- An exact mirror of the master development branch is hosted at
bitcoin-core/gui
. The new repository is used to track gui-only issues and pull requests. Global changes that happen to touch gui code still go to the main repo. - All pull requests will be merged into
bitcoin/bitcoin
. - Decision making process and maintainers will be identical for both repos.
Disadvantages
-
Review activity might decrease?
-
It doesn’t go far enough. bitcoin/bitcoin#3440 is proposing a modularized Bitcoin Core. The GUI could be an “add-on”, connected over RPC or capnproto (bitcoin/bitcoin#10102). Thus, the gui could even be hosted as a subtree or completely separate project.
Advantages
-
Review activity might increase? It is impossible to predict the future, but for example the
libsecp256k1
subtree has a lot of domain specific experts, maintainers and reviewers. I think longer term it makes sense to at least try this route for the gui as well. -
A smaller step is easier to undo when it turns out to come with any unforeseen downsides.
-
No substantial changes to the decision making progress.
-
Nothing changes in how developers set up their dev environment or how users build from the source. Also, the release binaries and process will stay exactly the same. No version drift. Finally, code sharing between the GUI and Bitcoin Core is not made any harder.
-
The organizational side. There are 72 open issues (~14%) and 61 open PRs (~16%) with the GUI label. If moved to its own repo, non-GUI developers wouldn’t have to be distracted with GUI-only issues and PRs and GUI enhancements. GUI developers have their own repo to focus on GUI development exclusively.
Implementation (outstanding TODOs)
-
Adjust maintainer merge script https://github.com/bitcoin-core/bitcoin-maintainer-tools/pull/57
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Create bitcoin-core/gui repository (empty or with master branch only)
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Assign all existing bitcoin core maintainers to the new repo
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Celebrate? :partying_face:
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Long-term: Think how long the grace period is for existing GUI related issues and pull requests. Issues can be transferred with a script after a grace period of some months?