Note This document is not a guide about how to migrate recipes to Conan v2.
Note This is a working document that will be updated as we walk this path. There are no dates intentionally, and if any they should be considered as an estimation, there are still some unknowns to provide certain steps and dates.
Conan v2 is under heavy development and it will be released in the following months. It comes with many improvements that will benefit recipes and users, and we are willing to adopt it.
It is a new major version that will come with many breaking changes. Lot of the features and syntax that we were used to in Conan v1 will no longer be available and will be supersedes by improved alternatives. All these alternatives should be backported to v1.x releases, so there will be a subset of features that will work using Conan v1 and v2.
Our main goal in ConanCenter during this migration process is to ensure that recipes work with v1 and v2 and to make the transition as smooth as possible for contributors and users. In the end we will be providing working recipes and binaries for both versions.
This process will require a lot of work also in the internals, we will keep communicating those changes and the relevant updates in the changelog. Here there are the main steps that we are planning for the following months.
Workers for Conan v2 will be ready for Windows, Macos and Linux alternatives.
Modern docker images with Conan v2 are already
available to use, for example conanio/gcc11-ubuntu16.04:2.0.0-pre.
Note that we will be using tag name 2.0.0-pre until there is an
actual Conan v2 release, this tag will use the latest pre-release
available (alpha, beta or release candidate).
We will start to run conan export using Conan v2 and the result will be
added to the comments by the bot. Failing this command won't make the
pull-request fail at this moment, but we expect contributors to start
gaining awareness about changes in Conan v2.
We want to provide a Conan recipe's linter in this repository. We will add warnings and errors to it following the pace dictated by the community. The purpose is that this linter will fail pull-requests if there is any error and, this way, we can start to migrate small (and easy) bits of recipes... and ensure that future pull-requests don't introduce regressions.
This linter can (and surely will) implement some of the checks that are being currently done by hooks, but the purpose is not replace them:
- hooks are really useful from the CLI, and are easier to install and run.
- linter provides much better output in GitHub interface.
The same way we export all the recipes every night using Conan v1, we will run something similar using Conan v2 and report the results to an issue in this repository.
It will help us to know how many recipes are fixed at a given time and think about efforts and impact of next steps.
Add CI running Conan v2 (hidden)
We will start working on a CI running Conan v2. Once recipes start to be exported successfully, next step is to start building the packages.
We are going to prepare the CI and start running it behind the scenes (sorry, at this moment hidden to users) in order to understand and experiment ourself some challenges that will come with Conan v2: syntax, configuration defaults,...
Once the errors start to make sense, we will start to provide these outputs in pull-requests (although successful builds using v2 won't be required to merge). Again, we expect some contributors to be aware of these errors, maybe try to fix those builds, and for sure report feedback.
During all this time, the plan is to move linter warnings to errors, one
by one and taking into account the effort required to fix them. With the
help of the linter more recipes should start to work (just conan export)
using Conan v2.
When a significant number (TBD) of recipes start to be exported successfully, we will turn those export warnings into actual errors and they will be become required to merge the pull-requests
Next step is to start running and reporting the results of the builds using v2 for all the configurations, like we do for Conan v1. At this time all pull-requests need to work with v1 and v2 to be merged.
Packages built using Conan v2 are available for users on conancenter remote.
ConanCenter webpage will start to show relevant information related to v2 packages and, eventually, v2 information will be the only available.
After this process in completed, we will consider the deprecation and decommission of the infrastructure to generate v1 packages.
The change should occur by steps, less used configurations, like older compiler versions, will be dropped first. Any changed will notified before to occur, so users can be prepared.