Enable more CI warnings (#347)

Enable more CI warnings

### Motivation

Fixes #332 and re-enables warnings as errors as we don't have deprecation warnings in our tests anymore.

### Modifications

Enabled a few previously disabled warnings/errors.

### Result

Stricter CI.

### Test Plan

The CI on this PR.


Reviewed by: PeterAdams-A

Builds:
     ✔︎ pull request validation (5.10) - Build finished. 
     ✔︎ pull request validation (5.8) - Build finished. 
     ✔︎ pull request validation (5.9) - Build finished. 
     ✔︎ pull request validation (compatibility test) - Build finished. 
     ✔︎ pull request validation (docc test) - Build finished. 
     ✔︎ pull request validation (integration test) - Build finished. 
     ✔︎ pull request validation (nightly) - Build finished. 
     ✔︎ pull request validation (soundness) - Build finished. 

#347

Sources/_OpenAPIGeneratorCore/Extensions/Foundation.swift

@@ -13,6 +13,12 @@
 //===----------------------------------------------------------------------===//
 import Foundation
 
+#if compiler(>=5.11)
+extension FileHandle: @retroactive TextOutputStream {}
+#else
+extension FileHandle: TextOutputStream {}
+#endif
+
 extension InMemoryInputFile {
     /// Creates a new in-memory file by reading the contents at the specified path.
     /// - Parameter url: The path to the file to read.
@@ -23,7 +29,7 @@ extension InMemoryInputFile {
 /// File handle to stderr.
 let stdErrHandle = FileHandle.standardError
 
-extension FileHandle: TextOutputStream {
+extension FileHandle {
     /// Writes the given string to the file handle.
     ///
     /// This method writes the provided string to the file handle using its UTF-8

Sources/swift-openapi-generator/Extensions.swift

@@ -16,7 +16,17 @@ import ArgumentParser
 import _OpenAPIGeneratorCore
 import Yams
 
-extension URL: ExpressibleByArgument {
+#if compiler(>=5.11)
+extension URL: @retroactive ExpressibleByArgument {}
+extension GeneratorMode: @retroactive ExpressibleByArgument {}
+extension FeatureFlag: @retroactive ExpressibleByArgument {}
+#else
+extension URL: ExpressibleByArgument {}
+extension GeneratorMode: ExpressibleByArgument {}
+extension FeatureFlag: ExpressibleByArgument {}
+#endif
+
+extension URL {
 
     /// Creates a `URL` instance from a string argument.
     ///
@@ -25,9 +35,6 @@ extension URL: ExpressibleByArgument {
     public init?(argument: String) { self.init(fileURLWithPath: argument) }
 }
 
-extension GeneratorMode: ExpressibleByArgument {}
-extension FeatureFlag: ExpressibleByArgument {}
-
 extension CaseIterable where Self: RawRepresentable, Self.RawValue == String {
 
     /// A string representation of the raw values of all the cases,

docker/docker-compose.2204.510.yaml

@@ -11,10 +11,7 @@ services:
     image: *image
     environment:
       - WARN_AS_ERROR_ARG=-Xswiftc -warnings-as-errors
-      # SwiftSyntax currently imports a module it does not explicitly depend
-      # on and so we must disable this for the time being.
-      # - IMPORT_CHECK_ARG=--explicit-target-dependency-import-check error
+      - IMPORT_CHECK_ARG=--explicit-target-dependency-import-check error
       - STRICT_CONCURRENCY_ARG=-Xswiftc -strict-concurrency=complete
-
   shell:
     image: *image

docker/docker-compose.2204.58.yaml

@@ -11,20 +11,8 @@ services:
   test:
     image: *image
     environment:
-      # Because OpenAPI supports deprecation, the generated code could include
-      # deprecated symbols, which will produce warnings.
-      #
-      # We'll disable -warnings-as-errors for now and revisit this when we
-      # refactor the compilation of the generated code into a separate
-      # pipeline.
-      #
-      # - WARN_AS_ERROR_ARG=-Xswiftc -warnings-as-errors
-
-      # SwiftSyntax currently imports a module it does not explicitly depend
-      # on and so we must disable this for the time being.
-      # - IMPORT_CHECK_ARG=--explicit-target-dependency-import-check error
-
+      - WARN_AS_ERROR_ARG=-Xswiftc -warnings-as-errors
+      - IMPORT_CHECK_ARG=--explicit-target-dependency-import-check error
       - STRICT_CONCURRENCY_ARG=-Xswiftc -strict-concurrency=complete
-
   shell:
     image: *image

docker/docker-compose.2204.59.yaml

@@ -12,10 +12,7 @@ services:
     image: *image
     environment:
       - WARN_AS_ERROR_ARG=-Xswiftc -warnings-as-errors
-      # SwiftSyntax currently imports a module it does not explicitly depend
-      # on and so we must disable this for the time being.
-      # - IMPORT_CHECK_ARG=--explicit-target-dependency-import-check error
+      - IMPORT_CHECK_ARG=--explicit-target-dependency-import-check error
       - STRICT_CONCURRENCY_ARG=-Xswiftc -strict-concurrency=complete
-
   shell:
     image: *image

docker/docker-compose.2204.main.yaml

@@ -11,20 +11,8 @@ services:
   test:
     image: *image
     environment:
-      # Because OpenAPI supports deprecation, the generated code could include
-      # deprecated symbols, which will produce warnings.
-      #
-      # We'll disable -warnings-as-errors for now and revisit this when we
-      # refactor the compilation of the generated code into a separate
-      # pipeline.
-      #
-      # - WARN_AS_ERROR_ARG=-Xswiftc -warnings-as-errors
-
-      # SwiftSyntax currently imports a module it does not explicitly depend
-      # on and so we must disable this for the time being.
-      # - IMPORT_CHECK_ARG=--explicit-target-dependency-import-check error
-
+      - WARN_AS_ERROR_ARG=-Xswiftc -warnings-as-errors
+      - IMPORT_CHECK_ARG=--explicit-target-dependency-import-check error
       - STRICT_CONCURRENCY_ARG=-Xswiftc -strict-concurrency=complete
-
   shell:
     image: *image