CoreCLR VS source-build

Yes, that is true. I'm not sure about JVM implementation details but the reason the comment says "virtual and interface" calls is to outline the difference. Virtual calls in .NET are sufficiently close[0] to virtual calls in C++. Interface calls, however, are coded differently[1].

Also you are correct - virtual calls are not terribly expensive, but they encroach on ever limited* CPU resources like indirect jump and load predictors and, as noted in parent comments, block inlining, which is highly undesirable for small and frequently called methods, particularly when they are in a loop.

* through great effort of our industry to take back whatever performance wins each generation brings with even more abstractions that fail to improve our productivity

[0] https://github.com/dotnet/coreclr/blob/4895a06c/src/vm/amd64...

[1] https://github.com/dotnet/runtime/blob/main/docs/design/core... (mind you, the text was initially written 18 ago, wow)

Sort of, some topic are not relevant anymore, consider this - https://github.com/dotnet/coreclr/tree/master/Documentation/botr

Fairly advanced stuff but the Book Of The Runtime (BOTR) it's a invaluable resource

After that you can check out the The Book of the Runtime, which is the CoreCLR version of the previous book.

Technically the restrictions already exist, just as a part of the development experience.

- .NET Hot Reload is only implemented on Windows. It requires support in the .NET runtime, which is technically possible to implement, but the team has not gotten around to implementing it for years. This doesn't have to do with the issue around MS removing the "dotnet watch" command, it's for the "Edit and Continue" feature in IDEs.[1][2]

- MS was considering deprecating Omnisharp, the open-source language server that implements C# support for VS Code, and replacing it with a closed-source version. Since the announcement, commits to omnisharp-vscode have dropped off significantly. The lack of Omnisharp would mean there would be no real open-source C# development environment for Linux anymore, since MonoDevelop was abandoned a few years ago. [3]

[1] https://youtrack.jetbrains.com/issue/RIDER-31366/EditContinu...

[2] https://github.com/dotnet/coreclr/issues/23685

[3] https://github.com/omnisharp/omnisharp-vscode/issues/5276

The next step is to realize everything you think you know about .NET is just an abstraction. Next step is to learn about what is going on behind all that syntax sugar and facades. 1st step might be https://github.com/dotnet/coreclr/tree/master/Documentation/botr then go down the rabbit hole and have fun

Book of the Runtime

As for the books, back in the days I really enjoyed reading “CLR via C#" by Jeffrey Richter which helped a lot to understand what is under the hood. Other from that, try The Book of the Runtime

.NET applications are technically challenging for Linux distributions to package. https://github.com/dotnet/source-build/discussions/2960

Git Credential Manager indeed release a self-contained binary for Linux x86_64 (no arm64 yet), though the installation size is necessarily large (80 MB) to include the .NET runtime. git-credential-oauth Linux binaries (x86_64 and arm64) are much smaller at 5 MB. https://github.com/hickford/git-credential-oauth#comparison-...

It's recommended to build from source for Debian, at least. Here's the latest stable release of the SDK announcement: https://github.com/dotnet/source-build/discussions/3369

Unfortunately, packaging applications built on .NET is still a challenge for any OS that wants to build everything from source and doesn't allow network access. Like you say, duplicating nuget into os-app-package-manager is challenging. Even side from the duplication, we need to bootstrap the ecosystem, in particular dealing with cyclic dependencies and version explosion as a result of all the different versions of all the dependencies that an average dotnet application needs.

We are starting to work through it here: https://github.com/dotnet/source-build/discussions/2960. Any advice/tips/contributions would be welcome, I think.

If you want to build .NET Core yourself, Microsoft provides you with the steps necessary to do so here: https://github.com/dotnet/source-build

Maybe our definitions of open source are different, or maybe you're just shitting on Microsoft for your own reasons. Regardless of whatever your experiences have been with .NET in the past, they don't mirror the majority of the folks that use it everyday.

The C# compiler and parts of the supporting .NET runtime are written in C#, so yes there is a boot strapping issue. Other languages like Rust or even C compilers written in C have this problem.

For initial porting to a new system or processor architecture, the C++ part of CoreCLR (the main runtime for .NET) can be built with CMake and LLVM on the target system. The libraries can be cross-compiled on another system that already supports .NET and copied to the target system. Some Details are here:

https://github.com/dotnet/runtime/blob/main/docs/design/core...

For building from source to satisfy requirements Linux distributions, Microsoft has a system to build from source. My understanding from the last time I closely looked at it is some binary dependencies are de compiled to MSIL (the bytecode used by .NET). Since CoreCLR includes a MSIL assembler written in C++ (ilasm), it can bootstrap using these MSIL sources. But I have not looked at this project closely in a while and it evolved quite a lot while I was watching it. The system for the source build is here:

https://github.com/dotnet/source-build

Note that there's a bug with the version of dotnet from Fedora's repositories (basically any version built from source by distro maintainers) that breaks Omnisharp for a lot of projects. See https://github.com/dotnet/source-build/issues/2006

It's coming. Progress is being tracked here: https://github.com/dotnet/source-build/issues/1139