Updates mean you have to copy over all the code into your repo, which creates a large diff, and hope you aren't overwriting any local changes someone might have made.
It bloats your repo, both with the actual code, and the large diffs when you update it.
You have to manually track new versions, without something to tell you if new versions are available, or if your version has known security vulnerabilities.
If the dependency has it's own dependencies, you have to vendor those too recursively. And if multiple dependencies have the same transitive dependency, it is up to you to deduplicate them, and make sure you have a version compatible with all dependents.
Etc.
Disk is cheap.
Recursive dependencies have the same issues whether you vend them or not.
Ensuring that diffs to updated dependencies remain within a vendor folder is trivial.
So, what’s left?
> Disk is cheap
The biggest problem isn't (usually) disk space, or network bandwidth, it is that git operations slow down as the size of the repo grows. And it means that cloning or pulling the repo takes longer, which can be especially problematic for CI.
> Recursive dependencies have the same issues whether you vend them or not.
Package managers usually handle resolving recursive/transitive dependencies for you. Some have support for vendoring dependencies, but not all do. In theory, you could have similar tooling for vendoring dependencies, but in practice that often isn't the case.
These are all solvable problems IME. But it does mean you need people who are experienced at solving them or who care enough to learn.
> But it does mean you need people who are experienced at solving them or who care enough to learn.
That sounds like it's inconvenient to me.
The price of security and business continuity is the occasional inconvenience. Tale as old as time.
> Disk is cheap
If I want to upgrade the disk on my MacBook Pro, I need to buy a new MacBook Pro with a larger disk. If I want to upgrade the disk on my work laptop, I’m SOL.
> Ensuring that diffs to updated dependencies remain within a vendor folder is trivial.
It’s not obvious to me how putting the dependencies in a vendor folder solves the diff problem. Does every code host allow you to hide diffs to certain directories?
And what’s the advantageous scenario for vendored dependencies? Is it just when the mod proxy and the upstream code host go down at the same time?
> If I want to upgrade the disk on my MacBook Pro, I need to buy a new MacBook Pro with a larger disk
Is this a significant risk in reality? MBPs today come with a minimum of 1TB of storage. Even 5 years ago I think the minimum was 256 GB. This is more than large enough for all but the hugest repositories, even with vendored dependencies. And you can always plug in external SSDs or HDDs or connect to a network server. Let’s talk about actual problems, shall we?
> And what’s the advantageous scenario for vendored dependencies? Is it just when the mod proxy and the upstream code host go down at the same time?
This is a useful homework assignment. Ask your favorite LLM or consult some respected release engineering books. Also consult your local AppSec and infosec teams.