[SR-3313] Swift package manager should clone with depth 1 by default

[alblue]

Previous ID	SR-3313
Radar	None
Original Reporter	@alblue
Type	Improvement
Status	Resolved
Resolution	Won't Do

Additional Detail from JIRA

Votes	0
Component/s	Package Manager
Labels	Improvement
Assignee	None
Priority	Medium

md5: 2e0e90cba36b930978412b088062e00b

Issue Description:

In the source code, swift package manager clones with depth 10:

https://github.com/apple/swift-package-manager/blob/57c5be1db1c1e12e089dff02241ffbce5722fb0e/Sources/Get/Git.swift#L31-L34

try system(Git.tool, "clone",
"--recursive", // get submodules too so that developers can use these if they so choose
"--depth", "10",
url, dstdir.asString, environment: env, message: "Cloning (url)")

The additional depth is unnecessary and in almost all cases won't be used; in addition, a remote git server can serve a --depth 1 quicker than a --depth >1, because a --depth 1 clone is simply a pack of the current tree.

Current versions of Git document the ability to extend the depth at a later stage if desired, which means that on a case-by-case basis this can easily be extended:

http://stackoverflow.com/questions/6941889/is-it-safe-to-shallow-clone-with-depth-1-create-commits-and-pull-updates-aga#21217267

[aciidgh]

This is old resolution mechanism which is going away soon. In new model, SwiftPM will clone the entire repository which is preferable by github.

[swift-ci]

Comment by Josh Kasten (JIRA)

@aciidb0mb3r Could we reconsider the clone depth for SwiftPM?

Some repos have a long history with large files in them. Example, a github repo with releases where binary frameworks were checked in for every release.

The downsides if the clone depth isn't 1 or something low is:

1. Package takes a long time to import over a slow internet connection.

2. Package uses extra disk space for history that normally won't be used.

I real world example of this is the OneSignal-iOS-SDK is ~400 MiB in size due it's age and binary frameworks for Cocoapod releases.

OneSignal/OneSignal-iOS-SDK#721