[SR-12926] provide a way to get the SHA of the current package in code

[weissi]

Previous ID	SR-12926
Radar	rdar://problem/63888891
Original Reporter	@weissi
Type	New Feature

Additional Detail from JIRA

Votes	2
Component/s	Package Manager
Labels	New Feature
Assignee	None
Priority	Medium

md5: c119e8705c814a44ed478dbb1dec3864

relates to:

• SR-473 Add version constants to each package
• SR-4265 [SwiftPM] CURRENT_PROJECT_VERSION should be defined on generated-xcodeproj

Issue Description:

This needs design of course but in certain cases it's really helpful if the binary contains the version (ie. the current SHA (+ a "dirty" marker if modified)) of its package in the binary. Even better if accessible in code.

Potentially we could even embed something like Package.resolved into the binary too so that every module could get the information for all packages.

See also:

• embed NIO version in binaries apple/swift-nio#684

• embedded http client user-agent string should include library version swift-server/swift-aws-lambda-runtime#108

• Add a User-Agent when using the Lambda Runtime API swift-server/swift-aws-lambda-runtime#98 (comment)

[weissi]

@swift-ci create

[ktoso]

Just a thought, if we end up wanting to have a built-in rather than implement the same as a plugin that's fine as well:

If we had "extensible build tools" this could rather be solved as a plugin (again, if we had those), and this way it becomes "gather some resources and put them somewhere task".

I've built such thing many years ago for the java ecosystem for including git information https://github.com/git-commit-id/git-commit-id-maven-plugin what we found is that people may want to include various things, like marking things as "dev" if on some specific branch or for specific customer/build etc...

It might be nice to think about this as "how do we enable building this" rather than a built-in in SPM that would be less flexible. Such plugin would want to write a resource, and then the resource would use all the normal ways to get accessed (so https://github.com/apple/swift-evolution/blob/master/proposals/0271-package-manager-resources.md )