libgit2 VS ck

Everything that is replicated on the network is stored as a Git object, using the libgit2[0] library. This library uses hardened SHA-1 internally, which is called sha1dc (for "detect collision").

[0]: https://github.com/libgit2/libgit2/blob/ac0f2245510f6c75db1b...

This is delightful and I can't wait to try it out. Right now, the libgit2 project (https://github.com/libgit2/libgit2) has a custom HTTP git server wrapper that will throttle the responses down to a very slow rate. It's fun watching a `git clone` running over 2400 baud modem speeds, but it's actually been incredibly helpful for testing timeouts, odd buffering problems, and other things that crop up in weird network environments.

I'd love to jettison our hacky custom code and use something off-the-shelf instead.

I've built a UI on top of libgit2 and I wish that this blog post expanded on which new features are missing (sparse checkout?).

To quote: "The migration to Git Executable will allow us to resolve long-standing issues with GitKraken Client, such as poor LFS performance, SSH configuration support and many other features/performance improvements."

I agree on LFS performance on Windows. SSH config support is a pain due to libssh2 but openssh support is on the way (https://github.com/libgit2/libgit2/pull/6617).

There are many cons to using the Git executable itself (parsing output, error reporting, version handling). Seems to me that there's more to this?

I'm curious about the license change? This is an executable is it not? Invoking it as a separate process does not require you make the software calling it GPL so switching to MIT should have no affect in the common case.

If the authors really wanted a more permissive license, then instead of relicensing from AGPL to MIT they should have gone AGPL with linking exception. An example of a project that does this is libgit2 [1]. This licensing is more permissive but still permits the author to sell commercial licenses to those making closed-source code changes.

[1] https://github.com/libgit2/libgit2#license

Using libxlsxwriter and libgit, it's straightforward -- just putting the equivalent of git shortlog and lines added and removed into a line of cells.

Maybe I'm missing something, but x is not volatile and the compiler is free to assume that it is not modified concurrently outside the bounds of C's memory model. Compilers can and do hoist out loop invariants, and https://github.com/concurrencykit/ck/commit/b54ae5c4ace9b94442bbb46858449069f566d269 seems like an example of compilers doing what you say they don't. What am I missing?

Recommend checking out http://concurrencykit.org instead.

If you're interested in how other approaches work, or how one achieves concurrency on shared mutable state without mutual exclusion, would recommend checking out concurrency kit.

There are plenty of practical solutions to the safe memory reclamation problem in C. The language just doesn't force one on you.

From epoch-based reclamation (https://github.com/concurrencykit/ck/blob/master/include/ck_..., especially with the multiplexing extension to Fraser's classic scheme), to quiescence schemes (https://liburcu.org/), or hazard pointers (https://github.com/facebook/folly/blob/master/folly/synchron..., or https://pvk.ca/Blog/2020/07/07/flatter-wait-free-hazard-poin...)... or even simple using a type-stable (https://www.usenix.org/legacy/publications/library/proceedin...) memory allocator.

In my experience, it's easier to write code that is resilient to hiccups in C than in Java. Solving SMR with GC only offers something close to lock-freedom when you can guarantee global GC pauses are short enough... and common techniques to bound pauses, like explicitly managed freelists land you back in the same problem space as C.

ck - Concurrency primitives, safe memory reclamation mechanisms and non-blocking data structures. BSD-2-Clause

Indeed they do, https://github.com/concurrencykit/ck