I would not have taken a C++ role. But that's because I don't like C++. Could I learn C++? Presumably, I assume it'd take quite a bit longer than C# but I don't want to.

A lot of programming skill that's transferable from one role to another is also transferable from one general purpose language to another. Almost everything about programming generally is transferable. All the practical implications of architecture is transferable. All the theory is transferable. Data structures are transferable (albeit if you've got very narrow experience you may not be aware of just what's possible). A lot of high level APIs are transferable.

On the other hand corporate knowledge isn't. So, the fresh graduate hire who is an expert in your preferred language does not know that around here nobody above an Engineer Lead reads their Teams chat, and nobody above Group Manager reads email. They don't know that tweaking the CSS requires a Design Team Lead authorisation because once somebody made the text the wrong colour and branding were furious - and they equally don't know that "Normal Minor" changes take six months to approve around here so they should mark small changes "Urgent Minor" instead and then pester a Senior Engineer to OK them, but never pester a Senior Engineer if it needs a Config change because that is an ops problem and... you are going to need to hire internally if you actually need them to "hit the ground running".

Yes, there are differences, but they are not fundamental. And with google, it really takes little time to learn things on the go. And with a team sharing necessary experience it will take no time at all.

EDIT: "I might want someone who can hit the ground running" - this is luxury, so one wanting it gotta pay up... And such short projects where such quick ramp up is important perhaps will be a better suited for contracting out the work anyway.

(And if you are such a startup, you want mostly senior generalists anyway.)

[0] Well, this is also probably begging the question. For me that's part of the definition of senior. Based on resumes I see lately it's far from everyone's.

Sent them on a course and within a couple of weeks they were committing stuff with minimal review needed in terms of language things.

It's now been a year and they're still learning about our code base. For me it took about two-three years before I felt comfortable on my own in the most-used areas.

The lat thing I need about any of my colleagues is to learning all gotchas, at the same time as integrating into our team.

Some tech I'll argue against, other tech I will require.

Some tech is fundamental to a domain. Some tech is a nice to have. Some tech is just generic.

My current team will not hire anyone for a senior role, without Spark experience. No matter how good you are in C++...

An example close to my heart. The company I'm currently at had a totally ossified Spark monolith and data eng team because they only wanted Spark developers. Drop one C++ developer in there to start spreading the good news about data-oriented design and suddenly there are a dozen previously-intractable "big data" problems we can rip out of the ball of mud and run outside of the cluster. Drop in another SRE who doesn't know shit about Java but can actually write shell scripts, and hey alerts from bad orchestration from weekly to twice yearly.

Yeah if you have a Spark job, you probably need a Spark dev. But if you have a team of Spark devs, suddenly everything that involves more than 1MB of input data looks like a Spark problem and you're in for a real bad time in a couple years.

C++ programmers know map/reduce/filter too.

Thanks for generalizing Spark engineers to an insulting level, though.

I have no clue how you got that from what I wrote. I even said a Spark project needs a Spark dev!

It really sounds to me like you're the one generalizing from "the one C++ dev we hired couldn't do data engineering right at all" to "senior programmers are dangerous to us unless they are Spark developers" (which imo, is more indicative of serious deficiencies in your architecture / design process), to "all senior programmers crossing subdomains are dangerous."

Sure LLVM or C pro will cringe looking at my code. But the business problem is solved, by someone who is not LLVM/C pro, and there is no need for more of that LLVM/C skills for now at the organization...

I've often seen organizations spend 6 months or more to find the perfect Foo developer when they could have hired someone right away who had Foo-adjacent skills and was very willing to learn Foo.

Would you rather hire a developer with 20 years experience but only 3 in the language you want, or would you rather hire the guy who has 6 years experience in the language you want and that’s it?

Personally, I’d hire the former every single time, even though he didn’t have the requisite 5 years in the language.

Pretty much better to reduce the years on the resume.

Sometimes, the right tool for the job is just a hammer :-)

I think more pragmatic question in such situations however, is why the potential employer is requiring $A years of experience in $TECHNOLOGY. For example, why they need someone to be productive from the say day $N and what does it actually mean (for them) to be productive?..

IMHO getting to shared understanding of what drives such requirements can help find a better path forward for both sides.

Is that the right analogy, or is it more like requiring CUDA experience vs knowing OpenCL (or Vulcan/Metal/etc.)?

I haven’t done C or asm since college but haven’t forgotten the concepts. Probably know more now than then.

I my experience, when working in a programming job, your programming skills rather degrade quite fast if you are not actively working in your free time to work hard against this degradation.

I rather get better in programming almost exclusively by the side projects that I do in my free time.

So, I would rather say that x years of job experience show nothing; what is important is what you do in your free time (if such side projects are possible).

Engineer? Yes.

Someone with a solid track record and a good foundation and background should be able to pivot relatively quickly.