rfcs VS nix-ros-overlay

> (after eelco ignored the PR for quite a while, also!)

Clicking that link takes us to a PR that was opened on 2024-02-02. The initial response from the Nix author comes 7 minutes later. Puck has multiple back and forths with other members Github, but her next interaction with the Nix author comes the next day on 2024-02-03. This is also the first time in the conversation where she "reminds him ... to even read her PR message". There's a second interaction later that same day during which she does similar, but it's worth noting this is pointing to a different message and appears to be less a "reminder to read" and more re-iterating what they feel is their argument against the Nix author's own arguments. Puck then continues to have back and forth with other commenters but as of today, there has been no further comments from the Nix author after 2024-02-03, and no further comments from Puck after 2024-02-08.

This hardly to my mind qualifies either as "having to remind him multiple times to even read her PR message at all" or "after eelco ignored the PR for quite a while, also!" So as I said it's a fairly weak claim, and feels more like a "bastard eating crackers" reaction to the PR than an actual showing of poor behavior.

As for the "Meson example", I didn't ignore it. As I stated in my comment, I had at that point read two of the referenced discussions in detail, and thus commented on them. I didn't comment in the "Meson example" for the simple reason that I hadn't read it.

I have read it now, and equally find it confusing.

1) The claim in the letter is that the proposal has "passed RFC, for five years", yet the RFC itself only appears to have been opened 2022-08-24. It's been a while since grade school for me, and I'll admit COVID has warped all our sense of time, but I'm pretty sure 2022 is not 5 years ago.

2) The first completed working implementation of the change doesn't appear to have been done until 2023-01-18 (https://github.com/NixOS/rfcs/pull/132#issuecomment-13874661...). Again this is much less than 5 years old.

3) On 2023-03-20, the author of the PR for this change states:

> the RFC has made it past most of the early stages and the current goal is to achieve parity with the current buildsystem before replacing it.

(https://github.com/NixOS/rfcs/pull/132#issuecomment-14768433...)

Again, this doesn't seem to fit at all with the claim that the proposal has "passed RFC, for five years"

4) On 2023-11-01, the Nix author themselves asks for updates on the RFC implementation, an action which doesn't seem congruent with someone who is willy nilly single handedly blocking things and being a disruption to the process. And the author of the PR states:

>the main block is actually a lack of free time for the main devs!

(https://github.com/NixOS/rfcs/pull/132#issuecomment-17890770...)

This doesn't seem to point to evidence that the Nix author is single handedly holding up this process.

5) On 2024-03-21 the PR author notes:

> currently working on adding support to build nix-perl, waiting for assistance

(https://github.com/NixOS/rfcs/pull/132#issuecomment-20135356...)

Not to sound like a broken record, but if the issue isn't finished as of a few weeks ago, it can hardly be considered to be held up by the Nix author for 5 years.

I agree that one of the links in the open letter is to a comment on a PR from 2019, which is indeed 5 year ago, and does indeed contain the Nix author commenting that they are skeptical of the change because "he doesn't know meson but knows his own build system". But given that there's an entire wealth of history on the topic since then, including progress on the feature that appears completely unobstructed by the Nix author and an open PR that is a mere 3 weeks old for a current implementation, I find myself again unconvinced of this rampant bad behavior on the part of the Nix author. And I reiterate again that these complaints are very weak and don't do much to support the open letter at best, and act as contrary evidence at worst.

Again there might be other context to be had that is missing, but if one is going to write a massive "open letter" complaining about bad behavior, I expect the links in that letter to point to actual bad behavior, and or provide the relevant context necessary to show how what appears to be normal dissent is a passive aggressive continuation of obstruction. I have to assume the links one provides in an open letter is their strongest evidence, and if this is all the authors have... I am unconvinced.

Nix with dynamic derivations (RFC92) could potentially beat this curse.

https://github.com/NixOS/rfcs/blob/master/rfcs/0092-plan-dyn...

See: A plan to stabilize the new CLI and Flakes incrementally https://github.com/NixOS/rfcs/pull/136

NixOS recently introduced "problem" infrastructure to deal with such problems more gracefully and explicitly:

https://github.com/NixOS/rfcs/blob/master/rfcs/0127-issues-w...

For some more context: Flawed as they are, Flakes solve a large number of problems Nix experiences without them. This is why I, and presumably many others, use them even in their current experimental state.

An RFC was recently accepted to commit to forming a plan towards stabilization of Flakes: https://github.com/NixOS/rfcs/pull/136

Personally, I don't believe there won't be any breaking changes, but I also believe that the stabilization of Flakes is still a ways away and hope that there will be a reasonable migration path.

NixOS needs to merge https://github.com/NixOS/rfcs/pull/133 to solve the issue

I believe this might be due to me also using the ROS overlay for Nix (https://github.com/lopsided98/nix-ros-overlay). Some packages that I'm using from ROS also require PCL, so I suspect that Nix might be ignoring my CUDA-enabled overlay and using the regular PCL package in order to meet the required dependencies. I'm not too sure how to confirm this...

Thanks for the response!

> This is difficult to answer without knowing more details.

The situation specifically is the ROS ecosystem, where metadata is managed in these package.xml files:

https://github.com/ros2/rclcpp/blob/master/rclcpp/package.xm...

The federated nature of the ecosystem has led to a culture where it's very normal to be building dozens of these at once, in the same workspace together, often from multiple repos (the repo above has four in it). So there are several build tools which automate the work of examining a source workspace and building all the packages within it in the correct topological order, respecting build_depend tags. The newest of these tools (colcon) has actually made the package.xml optional in many cases, as it can examine CMakelists, setup.py, BUILD, etc, and discover for itself what the dependencies are.

Your "distribution" of ROS is formed by listing all the packages and repos in this big file, for which there is other tooling to manage pulling dependency sources, whatever: https://github.com/ros/rosdistro/blob/master/foxy/distributi...

Anyway, so the existing ROS/nix efforts (1) seem to basically consume all of this package/distribution metadata at once and generate a giant parallel structure of nix definitions (eg https://github.com/lopsided98/nix-ros-overlay/blob/master/di...), which I fear would be completely opaque to users and any system which required everyone to leave behind these existing workflows would be an immediate non-starter.

I think the ideal scenario (and what it would look like if I built this myself based on debs) would be that you could source the "base" workspace as usual (enter the nix-shell?), and check out source, build packages as usual with colcon, the usual workspace-building tool, but there'd be an extra plugin/verb/flag for it, which would make it build each package as a nix package instead of into the usual installspace. The verb would generate the nix definitions on the fly, and probably handle the invocation and build-parallelism side of it as well.

[1]: https://github.com/acowley/ros2nix, https://github.com/lopsided98/nix-ros-overlay