Pretty cool. I didn't know there were groups using Haskell at NASA.
My suspicion is that once it's generally accepted as part of the kernel, things may change.
If the rust community wants rust to be used in safety-critical, my personal view is that they need to prioritize robustness and stability of the rust ecosystem as a whole over frequent changes to the language or libraries to save 1-2 lines of code.
Breaking changes to APIs and tool changes are a big issue in general, so they are best avoided (almost every time some introduces a breaking change that we are forced to adopt, we have to spend thousands of dollars (in time) to adapt). It's best to take longer to release a tool, but when you do it, make sure it'll work for a long time.
We recently had this case with a tool and our project was delayed by several weeks because someone replaced a version of a tool in homebrew that introduced a breaking change. We hit multiple bugs during the upgrade.
A mission that flies won't depend on homebrew, but it would be very plausible for a bug to be fixed in a version that pulls a dependency with a higher version number, and for it to be impossible or impractical to upgrade only one or two packages. In particular (and I don't "speak" rust), if your compiler comes with core libraries that necessarily need a version of the compiler to work, you want those to be de-coupled and the core API not to change.
Please be aware that this is just my personal opinion. I don't speak on behalf of any agencies.
> Breaking changes to APIs and tool changes are a big issue in general, so they are best avoided
There seem to be two different camps in the rust world. Any crates that have to do with web (orthogonal to but not distinct from async) or some GUI-related aspects seem to be constantly breaking in major ways between releases, way too often to actually keep up with. Anything else in the rust world, such that someone coming from a traditional C/C++ background would be interacting with, has a much more mature ecosystem around it w/ saner breakage (i.e. only when/where necessary and typically only changing a name or restructuring a type, but not "let's wholly rearchitecture both our own code and the code of anyone using this in the wild" kind of thing).
I've been betting on creating good software that survives for decades, but most people just want quick fixes and new features, and few are willing to put in the time to "do the homework" (that is, clean up the code, debug it, benchmark it, reduce it, modularize it, etc.). Over time, with more and more fixes and features, code rots and the maintenance burden increases.
People seem to be creating open source like it's free, with no regards for the time and effort put before. Every solution we create adds to the global maintenance burden of the community. We need to set processes in place that make open source code better over time, not bigger.
> live with developing processes to stay on top of updates like the rest of us?
NASA follows very robust software engineering processes (even for research projects like e.g., Copilot and, to a lesser extend, Ogma). It would not be able to do what it does if it didn't.
This is a topic for a longer discussion and definitely not to be had here, but I will say that it's not conductive to a constructive discussion to see it as a problem with our processes, or us ("developing processes to stay on top of updates", "like the rest of us").
The people who work on these things are smart. This is a topic we've had long discussions on. If it was obvious or viable to fix internally, we would have done it already.
I have been programming in particular in Haskell for 20y. I've worked for all kinds of companies and organizations, big and small, for the last 18y. I am like the rest of us. The problem is not exclusive to NASA, and NASA's processes are not to blame here.
It's a problem with how to build languages and ecosystems.
On the dependency front, Rust solves this about as well as you can hope for at the language level since dependencies between components don’t imply anything else about the dependency chain. I was just trying to convey that at that point there’s no way I can think of to reduce the cost of upgrading unless you make agreements with your exact SW dependencies about what versioning and changes look like for them (for general OSS that’s not generally tenable as NASA is likely to be a very small use case compared with the number of environments a popular package might get deployed to). That works in some cases but there’s no way to enforce that and nothing any language can do about it.
Generally I’ve found that organizations ossify their dependency chain on the assumption of “if it ain’t broke don’t fix it”. I’m not sure I buy that because that’s just tech debt that starts accruing and it’s better to just always pay a little bit of money along the way. Of course I don’t have any experience running teams on the kinds of problem domains NASA focuses on so I can’t speak to which development process is better for that use case. All I can note is that using off the shelf software and reducing the reliability requirements on as many components as possible generally results in a cheaper outcome (eg the Mars drone). When you’re in that domain you’re out of the high reliability domain of expensive space rocket launches and into more of the traditional SW development processes. Generally I’ve seen Rust libraries do semver better than most since that’s culturally the expectation. Even with Semver though you’re stuck if the library authors decide to go to the next major version.
This is a topic for a longer discussion and definitely not to be had here.