Comment by pm90
3 days ago
Its oddly fascinating that Microsoft has managed to survive for so long with ancient/bad tools for software engineering. Almost like “life finds a way” but for software dev. From the outside it seems like they are doing better now after embracing OSS/generic dev tools.
At one point source depot was Toincredibly advanced, and there are still features that it had that git doesn't. Directory mapping being a stand out feature! Being able to only pull down certain directories from a depot and also remap where they are locally, and even have the same file be in multiple places. Makes sharing dependencies across multiple projects really easy, and a lot of complicated tooling around "monorepos" wouldn't need to exist if git supported directory mapping.
(You can get 80% of the way there with symlinks but in my experience they eventually break in git when too many different platforms making commits)
Also at one point I maintained an obscenely advanced test tool at MS, it pounded through millions of test cases across a slew of CPU architectures, intermingling emulators and physical machines that were connected to dev boxes hosting test code over a network controlled USB switch. (See: https://meanderingthoughts.hashnode.dev/how-microsoft-tested... for more details!)
Microsoft had some of the first code coverage tools for C/C++, spun out of a project from Microsoft Research.
Their debuggers are still some of the best in the world. NodeJS debugging in 2025 is dog shit compared to C# debugging in 2005.
I never understood the value of directory mapping when we used Perforce. It only seemed to add complexity when one team checked out code in different hierarchies and then some builds worked, some didn’t. Git was wonderful for having a simple layout.
You might feel differently if you worked on just a few directories in a giant repo. Sparse client views were a great feature of SD.
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As always, git's answer to the problem is "stop being afraid of `git submodule`."
Cross-repo commits are not a problem as long as you understand "it only counts as truly committed if the child repo's commit is referenced from the parent repo".
Git submodules are awful. Using subversion's own submodule system should be mandatory for anyone claiming Git's implementation is somehow worthwhile or good.
> it only counts as truly committed if the child repo's commit is referenced from the parent repo
This is a big problem in my experience. Relying on consumers of your dependency to upgrade their submodules isn't realistic.
Ok, but now tell me your real thoughts on sysgen. ;-)
> git supported directory mapping.
Is this a "git" failure or a "Linux filesystems suck" failure?
It seems like "Linux fileystems" are starting to creak under several directions (Nix needing binary patching, atomic desktops having poor deduplication, containers being unable to do smart things with home directories or too many overlays).
Would Linux simply sucking it up and adopting ZFS solve this or am I missing something?
How is that related? I don’t think anyone would suggest ntfs is a better fit for these applications. It worked because it was a feature of the version control software, not because of file system features.
What would ZFS do for those issues? I guess maybe deduplication, but otherwise I'm not thinking of anything that you can't do with mount --bind and overlays (and I'm not even sure ZFS would replace overlays)
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Let’s not forget that Microsoft developed a lot of tools in the first place, as in, they were one of the companies that created things that didn’t really exist before Microsoft created them.
Git isn’t even very old, it came out in 2005. Microsoft Office first came out in 1990. Of course Office wasn’t using git.
Office is a package including things like Word and Excel. Word itself came out in 1984 for the first Macintosh. Windows OS did not yet exist.
Some examples would be useful here. Not knocking MS tools in general but are there any that were industry fists? Source code control for example existed at least since SCCS which in turn predates Microsoft itself.
Microsoft rarely did or does anything first. They are typically second or third to the post and VC is no different.
Most people don’t know or realize that Git is where it is because of Microsoft. About 1/2 of the TFS core team spun out to a foundation where they spent several years doing things like making submodules actually work, writing git-lfs, and generally making git scale.
You can look for yourself at the libgit2 repo back in the 2012-2015 timeframe. Nearly the whole thing was rewritten by Microsoft employees as the earliest stages of moving the company off source depot.
It was a really cool time that I’m still amazed to have been a small part of.
Of course that's only half the story - Microsoft invents amazing things, and promptly fails to capitalize on them.
AJAX, that venerable piece of kit that enabled every dynamic web-app ever, was a Microsoft invention. It didn't really take off, though, until Google made some maps with it.
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Google used Perforce for years and I think Piper still has basically the same interface? So no, MSFT wasn’t ridiculously behind the times by using Source Depot for so long.