[SR-1119] Process.arguments isn't available when 'main' isn't generated by Swift

[belkadan]

Previous ID	SR-1119
Radar	None
Original Reporter	@belkadan
Type	Bug
Status	Resolved
Resolution	Done

Additional Detail from JIRA

Votes	0
Component/s	Standard Library
Labels	Bug, StarterBug
Assignee	@CodaFi
Priority	Medium

md5: 0f34c53480ec273df4a5db445681eff4

Issue Description:

If you have a Swift library that's loaded into a non-Swift executable, or a mixed-source executable whose main function isn't generated from Swift, we never get the chance to set argc and argv on Process, resulting in traps when a client attempts to access them. We should give up on using the "real" argc and argv (i.e. the ones passed to main) and just use _NSGetArgv() on Darwin, /proc/(pid)/cmdline on Linux, and whatever the appropriate API is on FreeBSD, initializing the arguments lazily (and independently from main.

(Alternately, we could put a static initializer in the Swift standard library, at least on Darwin platforms. But static initializers are evil incur a runtime cost on every client, so that's not a great answer.)

[CodaFi]

Playing devil's advocate: Perhaps a hybrid approach? If we know how to get "real" args on a select few platforms we can fall back to the others on everybody else.

[CodaFi]

Fun how these things work out. apple/swift#3108