Fix Linux compatibility issues

[abdimaye]

Issue #1506

List of changes:

• Swift-tools-version:5.3
• Optionally import swift-crypto for Linux
• Create Crypt wrapper for crypto functions
• Import FoundationNetworking - required due to new recent move of network-related objects https://stackoverflow.com/questions/58592508/how-can-i-use-foundations-urlrequest-type-on-linux
• Create StringEncoding wrapper and map encoding for Linux

[apollo-cla]

@abdimaye: Thank you for submitting a pull request! Before we can merge it, you'll need to sign the Apollo Contributor License Agreement here: https://contribute.apollographql.com/

[designatednerd]

@abdimaye can you elaborate a bit on what's still not working?

[abdimaye]

@abdimaye can you elaborate a bit on what's still not working?

Planning to add the details to the list of outstanding errors later today 👍

[designatednerd]

Some thoughts that might help looking over those errors:

• I'm pretty sure for Bundle+Helpers you can just throw an if not linux around the contents of that file since it deals with Bundle stuff that I'm almost positive doesn't exist in the Linux version of Foundation.
• Is URLRequest not one of the things that's in FoundationNetworking? That's a significant surprise if not.
• I think for the URLSessionTaskMetrics and URLSessionStreamTask you should be able to use an unavailable marker for linux on the enclosing methods.
• Not sure what Foundation for Linux has got to figure out the string encoding, but you'd probably need to do something similar to what you're doing with Crypt to create a protocol to handle those
• Not sure what the hell is going on with the JSON error, tbh.

[abdimaye]

@designatednerd sorry I've been ghost! I think the encoding issue was the last. Looks like there are some merge conflicts also which I'll take a peek at later.

[designatednerd]

Awesome work - though I'm a bit confused as to why the tests aren't running on this at all. I'll poke at it this afternoon.

[designatednerd]

I'd also like to know if you have suggestions for at least making sure things continue to build on linux - what linux setup should we be using for tests, etc

[designatednerd]

I wonder if it wasn't building because this was a draft from a forked repo - can you make another commit please?

[abdimaye]

I'd also like to know if you have suggestions for at least making sure things continue to build on linux - what linux setup should we be using for tests, etc

I've now added a Dockerfile and build script for linux. Not entirely sure about the testing as I'm still trying to figure this out...

[designatednerd]

Taking a stab at adding a linux build to the matrix...apologies for pushing to your branch but it's not going to work on any other branch at the moment 😛

[designatednerd]

Woof. Running into some serious issues around the fact that even though we're specifically saying only import Crypto on linux, it's still saying it's a dependency on macOSX. I have no idea why this wasn't failing the build before - I'm going to try to do some swift 5.3 stuff on a separate branch to try and disentangle a bunch of changes I need to make to file structure because of resources from this PR

[designatednerd]

Looks like the SQlite sub-lib is not compiling on linux since it uses a bunch of stuff which is iOS specific. Ugh, I wish platform restrictions per target were a thing.

I'll have to reach out to the swift forums about why things are trying to import Crypto lib even though it specifically says it should only be brought in on linux

[abdimaye]

Looks like the SQlite sub-lib is not compiling on linux since it uses a bunch of stuff which is iOS specific. Ugh, I wish platform restrictions per target were a thing.

I'll have to reach out to the swift forums about why things are trying to import Crypto lib even though it specifically says it should only be brought in on linux

😕 Would it be reasonable to skip any tests which have platform specific dependencies for this first iteration?

[designatednerd]

Unfortunately the problem is not that the tests won't run, it's that the libraries won't even build. Again, I'm not sure why this wasn't showing up as a problem earlier. 😭

[abdimaye]

Have you tried xcodebuild? Something like xcodebuild -scheme Apollo?

[designatednerd]

That's what we're doing on the iOS and mac tests already, unfortuantely. And it's still giving us problems.

[abdimaye]

Found another issue that's kind of related to this - type checking queryDocument would timeout on linux. Here's the PR from my colleague: apollographql/apollo-tooling#2198

[abdimaye]

Completely forgot about this! I won't be looking into this further so closing PR.