Git VS git

Boy, I can't find this either (but also, the kernel mailing list is _really_ difficult to search). I really remember Linus saying something like "it's not a real SCM, but maybe someone could build one on top of it someday" or something like that, but I cannot figure out how to find that.

You _can_ see, though, that in his first README, he refers to what he's building as not a "real SCM":

https://github.com/git/git/commit/e83c5163316f89bfbde7d9ab23...

Here is the direct link, as HN somehow removes the query string: https://github.com/git/git/commits?author=peff&since=2023-10...

I understand all that.

I'm saying, if you write a survey and one of the possible answers is "diff", but you don't clearly define what you mean by "diff", then don't be surprised if respondents use any reasonable definition that makes sense to them. Ask an ambiguous question, get a mishmash of answers.

The thing that Git uses for packfiles is called a "delta" by Git, but it's also reasonable to call it a "diff". After all, Git's delta algorithm is "greatly inspired by parts of LibXDiff from Davide Libenzi"[1]. Not LibXDelta but LibXDiff.

Yes, how Git stores blobs (using deltas) is orthogonal to how Git uses blobs. But while that orthogonality is useful for reasoning about Git, it's not wrong to think of a commit as the totality of what Git does, including that optimization. (Some people, when learning Git, stumble over the way it's described as storing full copies, think it's wasteful. For them to wrap their heads around Git, they have to understand that the optimization exists. Which makes sense because Git probably wouldn't be practical if it lacked that optimization.)

The reason I'm bringing all this up is, if you're trying to explain Git, which is what the original article is about, then it's very important to keep in mind that someone who is learning Git needs to know what you mean when you say "diff". Most people who already know Git would tend to gravitate toward the definition of "diff" that you're assuming (the thing that Git computes on the fly and never stores), but people who already know Git aren't the target audience when you're teaching Git.

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[1] https://github.com/git/git/blob/master/diff-delta.c

Didn't Git have a new default merge strategy, `ort` https://github.com/git/git/blob/master/Documentation/RelNote... ?

Yes, but you are referring to standalone scripts, not functions defined within a Bash script.

Compare for example the following helper code used for git command completion inside Bash and inside PowerShell.

Bash: https://github.com/git/git/blob/master/contrib/completion/gi...

Microsoft had a bunch of solutions to handle their massive Windows repo: VFS for Git (GVFS), Scalar, and now it has a bunch of MS specific patches on top of the official git client, but apparently that one is also not required any more as partial clone is now supported on azure as well (which is another such implementation from Microsoft employees that made it to both GitHub and upstream git).

https://github.blog/2020-01-17-bring-your-monorepo-down-to-s...

https://devblogs.microsoft.com/devops/introducing-scalar/

https://github.com/microsoft/git

https://devblogs.microsoft.com/devops/git-partial-clone-now-...

That was discontinued (like multiple times under different names). And is moved into a git fork. https://github.com/microsoft/git

Interesting! It seems some of Scalar from late 2021 has already made it into the official git project's contrib dir [0]. It looks like Scalar is mostly an opinionated way to configure git [1], especially by using git partial-clone.

Git partial-clone looks almost perfect, except it only downloads and displays files explicitly added to the git sparse-checkout list. I want some "magic" vfs shenanigans that lets me view and browse the full repo exactly as if the full repo where checked out, but when I open a directory or file the contents are downloaded on-demand.

[0]: https://github.com/git/git/tree/master/contrib/scalar

[1]: https://github.com/microsoft/git/blob/vfs-2.37.0/Documentati...

Ironically, Microsoft has been a major contributor to improvements in git for handling large repos after Windows was migrated to git.

https://github.com/microsoft/git

300GB git repo... anyway, good to see there's work for merge in back to git proper, though it seems like that is still a work in progress (maybe) as https://github.com/Microsoft/git/ still seems pretty active.

This is well written and deserves my upvote, because sparse-checkout is part of git and knowing how it works is useful.

That said, there's absolutely no reason to structure your code in a monorepo.

Here's what I think GitHub is doing:

1) Encourage monorepo adoption

2) Build tooling for monorepos

3) Selling tooling to developers stranded in monorepos

Microsoft, which owns GitHub, created the microsoft/git fork linked in the article, and they explain their justification here: https://github.com/microsoft/git#why-is-this-fork-needed

> Well, because Git is a distributed version control system, each Git repository has a copy of all files in the entire history. As large repositories, aka monorepos grow, Git can struggle to manage all that data. As Git commands like status and fetch get slower, developers stop waiting and start switching context. And context switches harm developer productivity.

I believe that Google's brand is so big that it led to this mass cognitive dissonance, which is being exploited by GitHub.

To be clear, here are the two ideas in conflict:

* Git is decentralized and fast, and Google famously doesn't use it.

* Companies want to use "industry standard" tech, and Google is the standard for success.

Now apply those observations to a world where your engineers only use "git".

The result is market demand to misuse git for monorepos, which Microsoft is pouring huge amounts of resources into enabling via GitHub.

It makes great sense that GitHub wants to lean into this. More centralization and being more reliant on GitHub's custom tooling is obviously better for GitHub.

It just so happens that GitHub is building tools to enable monorepos, essentially normalizing their usage.

Then GitHub can sell tools to deal with your enormous monorepo, because your traditional tools will feel slow and worse than GitHub's tools.

In other words, GitHub is propping up the failed monorepo idea as a strategy to get people in the pipeline for things like CodeSpaces: https://github.com/features/codespaces

Because if you have 100 projects and they're all separate, you can do development locally for each and it's fast and sensible. But if all your projects are in one repo, the tools grind to a halt, and suddenly you need to buy a solution that just works to meet your business goals.

VFS for Git was superceded by https://github.com/microsoft/scalar and then many of the features were merged into mainline git, so what is left now is a thin shell around git features in the form of MS's forked git binary: https://github.com/microsoft/git