Raise minimum supported Swift version from 5.4 to 5.5 (#355)

Motivation:

SwiftNIO periodically drops support for older Swift versions. Now that 5.7 has been released, 5.4 will be dropped.

Modifications:

- Remove 5.4 specific Package.swift and docker-compose
- Update the 5.7 docker-compose to use the released 5.7 and move from focal (2004) to jammy (2204)
- Fix tools version in [email protected]
- Update docs

Results:

Minimum Swift version is 5.5

Author: glbrntt

[email protected]

@@ -1,4 +1,4 @@
-// swift-tools-version:5.4
+// swift-tools-version:5.5
 //===----------------------------------------------------------------------===//
 //
 // This source file is part of the SwiftNIO open source project

[email protected]

@@ -24,7 +24,15 @@ To depend on `swift-nio-http2`, put the following in the `dependencies` of your
 
     .package(url: "https://github.com/apple/swift-nio-http2.git", from: "1.19.2"),
 
-SwiftNIO HTTP2 1.21.x and later support Swift 5.4 and above. 1.20.x and earlier also support Swift 5.2 and 5.3. 1.17.x and earlier also support Swift 5.0 and 5.1.
+The most recent versions of SwiftNIO HTTP/2 support Swift 5.5 and newer. The minimum Swift version supported for SwiftNIO HTTP/2 releases are detailed below:
+
+SwiftNIO HTTP/2     | Minimum Swift Version
+--------------------|----------------------
+`1.0.0 ..< 1.18.0`  | 5.0
+`1.18.0 ..< 1.21.0` | 5.2
+`1.21.0 ..< 1.23.0` | 5.4
+`1.24.0 ...`        | 5.5
+
 
 ### `swift-nio-http2` 0.x
 

README.md

@@ -26,14 +26,11 @@ import XCTest
    @testable import NIOHPACKTests
    @testable import NIOHTTP2Tests
 
-// This protocol is necessary to we can call the 'run' method (on an existential of this protocol)
-// without the compiler noticing that we're calling a deprecated function.
-// This hack exists so we can deprecate individual tests which test deprecated functionality without
-// getting a compiler warning...
-protocol LinuxMainRunner { func run() }
-class LinuxMainRunnerImpl: LinuxMainRunner {
+@main
+@available(*, deprecated, message: "not actually deprecated. Just deprecated to allow deprecated tests (which test deprecated functionality) without warnings")
+class LinuxMainRunner {
    @available(*, deprecated, message: "not actually deprecated. Just deprecated to allow deprecated tests (which test deprecated functionality) without warnings")
-   func run() {
+   static func main() {
        XCTMain([
              testCase(CircularBufferExtensionsTests.allTests),
              testCase(CompoundOutboundBufferTest.allTests),
@@ -66,5 +63,4 @@ class LinuxMainRunnerImpl: LinuxMainRunner {
         ])
     }
 }
-(LinuxMainRunnerImpl() as LinuxMainRunner).run()
 #endif

Tests/LinuxMain.swift

@@ -1,4 +1,4 @@
-ARG swift_version=5.4
+ARG swift_version=5.7
 ARG ubuntu_version=focal
 ARG base_image=swift:$swift_version-$ubuntu_version
 FROM $base_image

docker/Dockerfile

@@ -3,26 +3,27 @@ version: "3"
 services:
 
   runtime-setup:
-    image: swift-nio-http2:20.04-5.7
+    image: swift-nio-http2:22.04-5.7
     build:
       args:
-        base_image: "swiftlang/swift:nightly-5.7-focal"
+        ubuntu_version: "jammy"
+        swift_version: "5.7"
         h2spec_version: "2.2.1"
 
   unit-tests:
-    image: swift-nio-http2:20.04-5.7
+    image: swift-nio-http2:22.04-5.7
 
   integration-tests:
-    image: swift-nio-http2:20.04-5.7
+    image: swift-nio-http2:22.04-5.7
 
   performance-test:
-    image: swift-nio-http2:20.04-5.7
+    image: swift-nio-http2:22.04-5.7
 
   h2spec:
-    image: swift-nio-http2:20.04-5.7
+    image: swift-nio-http2:22.04-5.7
 
   test:
-    image: swift-nio-http2:20.04-5.7
+    image: swift-nio-http2:22.04-5.7
     environment:
       - MAX_ALLOCS_ALLOWED_1k_requests_interleaved=43200
       - MAX_ALLOCS_ALLOWED_1k_requests_noninterleaved=42100
@@ -37,4 +38,4 @@ services:
       - MAX_ALLOCS_ALLOWED_stream_teardown_100_concurrent=293350
 
   shell:
-    image: swift-nio-http2:20.04-5.7
+    image: swift-nio-http2:22.04-5.7

docker/docker-compose.1804.54.yaml

@@ -98,14 +98,11 @@ def createLinuxMain(testsDirectory, allTestSubDirectories, files)
       file.write '   @testable import ' + testSubDirectory + "\n"
     end
     file.write "\n"
-    file.write "// This protocol is necessary to we can call the 'run' method (on an existential of this protocol)\n"
-    file.write "// without the compiler noticing that we're calling a deprecated function.\n"
-    file.write "// This hack exists so we can deprecate individual tests which test deprecated functionality without\n"
-    file.write "// getting a compiler warning...\n"
-    file.write "protocol LinuxMainRunner { func run() }\n"
-    file.write "class LinuxMainRunnerImpl: LinuxMainRunner {\n"
+    file.write "@main\n"
+    file.write '@available(*, deprecated, message: "not actually deprecated. Just deprecated to allow deprecated tests (which test deprecated functionality) without warnings")' + "\n"
+    file.write "class LinuxMainRunner {\n"
     file.write '   @available(*, deprecated, message: "not actually deprecated. Just deprecated to allow deprecated tests (which test deprecated functionality) without warnings")' + "\n"
-    file.write "   func run() {\n"
+    file.write "   static func main() {\n"
     file.write "       XCTMain([\n"
 
     testCases = []
@@ -121,7 +118,6 @@ def createLinuxMain(testsDirectory, allTestSubDirectories, files)
     file.write "        ])\n"
     file.write "    }\n"
     file.write "}\n"
-    file.write "(LinuxMainRunnerImpl() as LinuxMainRunner).run()\n"
     file.write "#endif\n"
   end
 end