GraphQL doesn't compile on Linux Swift 5.4

[adam-fowler]

Using Dockerfile

FROM swift:5.4 as build

WORKDIR /build
COPY ./Package.* ./
RUN swift package resolve

# Copy entire repo into container
COPY . .

RUN swift test --enable-test-discovery

I get these errors

#8 8.305 /build/Sources/GraphQL/Map/AnyCoder.swift:2058:22: error: '_cfTypeID' is inaccessible due to 'internal' protection level
#8 8.305         guard number._cfTypeID == CFBooleanGetTypeID() else {
#8 8.305                      ^~~~~~~~~
#8 8.305 Foundation.NSNumber (internal):45:27: note: '_cfTypeID' declared here
#8 8.305     override internal var _cfTypeID: CFTypeID { get }
#8 8.305                           ^
#8 8.305 [148/184] Compiling GraphQL Parser.swift
#8 8.305 /build/Sources/GraphQL/Map/AnyCoder.swift:2058:22: error: '_cfTypeID' is inaccessible due to 'internal' protection level
#8 8.305         guard number._cfTypeID == CFBooleanGetTypeID() else {
#8 8.305                      ^~~~~~~~~
#8 8.305 Foundation.NSNumber (internal):45:27: note: '_cfTypeID' declared here
#8 8.305     override internal var _cfTypeID: CFTypeID { get }
#8 8.305                           ^
#8 8.305 [149/184] Compiling GraphQL Source.swift
#8 8.305 /build/Sources/GraphQL/Map/AnyCoder.swift:2058:22: error: '_cfTypeID' is inaccessible due to 'internal' protection level
#8 8.305         guard number._cfTypeID == CFBooleanGetTypeID() else {
#8 8.305                      ^~~~~~~~~
#8 8.305 Foundation.NSNumber (internal):45:27: note: '_cfTypeID' declared here
#8 8.305     override internal var _cfTypeID: CFTypeID { get }
#8 8.305                           ^
#8 8.305 [150/184] Compiling GraphQL Visitor.swift
#8 8.305 /build/Sources/GraphQL/Map/AnyCoder.swift:2058:22: error: '_cfTypeID' is inaccessible due to 'internal' protection level
...

[alexsteinerde]

This issue seems to be introduced to the Foundation library with this commit: apple/swift-corelibs-foundation@75f3bac
I'm not sure if it is possible to make this property public again or if there is a workaround.

[alexsteinerde]

I just saw the official Jira issue for this (https://bugs.swift.org/browse/SR-464). This property is intended to be private. So I think there is no chance in getting this changed back in the Foundation source code.

[adam-fowler]

It looks like a lot of this code is based off the JSONEncoder/Decoder from Foundation. The majority of this code (at least in swift-corelibs-foundation) has been rewritten and does not depend on NSNumber anymore. Is it possible to re-write to avoid NSNumber?

[alexsteinerde]

I created a PR that fixes the build issue for me (I used the Dockerfile provided by you).
Please correct me if my solution is wrong.

If a re-write is possible I don't know. I'm not very familiar with the low level code to answer this question.

[adam-fowler]

Yeah looks to fix it. I hadn't thought of using CFGetTypeID.
Removing NSNumber will improve performance of the Coders. But I guess that can be done another time.