[Generator] Integrate the new URI and String coders (#226)

[Generator] Integrate the new URI and String coders

### Motivation

Depends on runtime changes from apple/swift-openapi-runtime#45.

Up until now, we relied on a series of marker and helper protocols `_StringConvertible` and `_AutoLosslessStringConvertible` to handle converting between various types and their string representation.

This has been very manual and required a non-trivial amount of work to support any extra type, especially `Date` and generated string enums.

Well, turns out this was an unnecessarily difficult way to approach the problem - we had a better solution available for a long time - `Codable`.

Since all the generated types and all the built-in types we reference are already `Codable`, there is no need to reinvent a way to serialize and deserialize types, and we should just embrace it.

While a JSON encoder and decoder already exists in Foundation, we didn't have one handy for encoding to and from URIs (used by headers, query and path parameters), and raw string representation (using `LosslessStringConvertible`). We created those in the runtime library in PRs apple/swift-openapi-runtime#44 and apple/swift-openapi-runtime#41, and integrated them into our helper functions (which got significantly simplified this way) in apple/swift-openapi-runtime#45.

Out of scope of this PR, but this also opens the door to supporting URL form encoded bodies (#182), multipart (#36), and base64 (#11).

While this should be mostly invisible to our adopters, this refactoring creates space for implementing more complex features and overall simplifies our serialization story.

### Modifications

- Updated the generator to use the new helper functions.
- Updated the article about serialization, shows how we reduced the number of helper functions by moving to `Codable`.
- Set the `lineLength` to 120 on the formatter configuration, it was inconsistent with our `.swift-format` file, and lead to the soundness script trying to update the reference files, but then the reference tests were failing. Since we're planning to sync these in #40, this is a step closer to it, but it means that it's probably best to review this PR's diff with whitespace ignored.

### Result

Now the generated code uses the new helper functions, allowing us to delete all the deprecated helpers in 0.2.0.

### Test Plan

Updated file-based reference, snippet, and unit tests.


Reviewed by: glbrntt

Builds:
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     ✔︎ pull request validation (nightly) - Build finished. 
     ✔︎ pull request validation (soundness) - Build finished. 

#226

Author: czechboy0

Package.swift

@@ -80,7 +80,7 @@ let package = Package(
         // Tests-only: Runtime library linked by generated code, and also
         // helps keep the runtime library new enough to work with the generated
         // code.
-        .package(url: "https://github.com/apple/swift-openapi-runtime", .upToNextMinor(from: "0.1.10")),
+        .package(url: "https://github.com/apple/swift-openapi-runtime", .upToNextMinor(from: "0.1.11")),
 
         // Build and preview docs
         .package(url: "https://github.com/apple/swift-docc-plugin", from: "1.0.0"),

Sources/_OpenAPIGeneratorCore/Extensions/SwiftFormat.swift

@@ -32,6 +32,7 @@ extension String {
             configuration.lineBreakAroundMultilineExpressionChainComponents = true
             configuration.indentConditionalCompilationBlocks = false
             configuration.maximumBlankLines = 0
+            configuration.lineLength = 120
             let formatter = SwiftFormatter(configuration: configuration)
             try formatter.format(
                 source: self,

Sources/_OpenAPIGeneratorCore/Translator/ClientTranslator/translateClientMethod.swift

@@ -30,7 +30,7 @@ extension ClientFileTranslator {
             left: "path",
             right: .try(
                 .identifier("converter")
-                    .dot("renderedRequestPath")
+                    .dot("renderedPath")
                     .call([
                         .init(label: "template", expression: .literal(pathTemplate)),
                         .init(label: "parameters", expression: pathParamsArrayExpr),

Sources/_OpenAPIGeneratorCore/Translator/CommonTranslations/translateStringEnum.swift

@@ -48,10 +48,12 @@ extension FileTranslator {
         let generateUnknownCases = shouldGenerateUndocumentedCaseForEnumsAndOneOfs
         let baseConformance =
             generateUnknownCases ? Constants.StringEnum.baseConformanceOpen : Constants.StringEnum.baseConformanceClosed
+        let conformances =
+            generateUnknownCases ? Constants.StringEnum.conformancesOpen : Constants.StringEnum.conformancesClosed
         let unknownCaseName = generateUnknownCases ? Constants.StringEnum.undocumentedCaseName : nil
         return try translateRawRepresentableEnum(
             typeName: typeName,
-            conformances: [baseConformance] + Constants.StringEnum.conformances,
+            conformances: [baseConformance] + conformances,
             userDescription: userDescription,
             cases: cases,
             unknownCaseName: unknownCaseName,

Sources/_OpenAPIGeneratorCore/Translator/CommonTypes/Constants.swift

@@ -151,13 +151,19 @@ enum Constants {
         static let baseConformanceClosed: String = "String"
 
         /// The types that every enum conforms to.
-        static let conformances: [String] = [
+        static let conformancesOpen: [String] = [
             "Codable",
             "Hashable",
             "Sendable",
-            "_AutoLosslessStringConvertible",
             "CaseIterable",
         ]
+
+        /// The types that every enum conforms to.
+        static let conformancesClosed: [String] = [
+            "Codable",
+            "Hashable",
+            "Sendable",
+        ]
     }
 
     /// Constants related to generated oneOf enums.
@@ -370,8 +376,11 @@ enum Constants {
         /// The substring used in method names for the JSON coding strategy.
         static let json: String = "JSON"
 
-        /// The substring used in method names for the text coding strategy.
-        static let text: String = "Text"
+        /// The substring used in method names for the URI coding strategy.
+        static let uri: String = "URI"
+
+        /// The substring used in method names for the string coding strategy.
+        static let string: String = "String"
 
         /// The substring used in method names for the binary coding strategy.
         static let binary: String = "Binary"

Sources/_OpenAPIGeneratorCore/Translator/Content/CodingStrategy.swift

@@ -18,8 +18,11 @@ enum CodingStrategy: String, Hashable, Sendable {
     /// A strategy using JSONEncoder/JSONDecoder.
     case json
 
-    /// A strategy using LosslessStringConvertible.
-    case text
+    /// A strategy using URIEncoder/URIDecoder.
+    case uri
+
+    /// A strategy using StringEncoder/StringDecoder.
+    case string
 
     /// A strategy that passes through the data unmodified.
     case binary
@@ -29,8 +32,10 @@ enum CodingStrategy: String, Hashable, Sendable {
         switch self {
         case .json:
             return Constants.CodingStrategy.json
-        case .text:
-            return Constants.CodingStrategy.text
+        case .uri:
+            return Constants.CodingStrategy.uri
+        case .string:
+            return Constants.CodingStrategy.string
         case .binary:
             return Constants.CodingStrategy.binary
         }

Sources/_OpenAPIGeneratorCore/Translator/Content/ContentInspector.swift

@@ -203,7 +203,7 @@ extension FileTranslator {
             {
                 diagnostics.emitUnsupportedIfNotNil(
                     chosenContent.1.encoding,
-                    "Custom encoding for JSON content",
+                    "Custom encoding for multipart/formEncoded content",
                     foundIn: "\(foundIn), content \(contentType.originallyCasedTypeAndSubtype)"
                 )
             }
@@ -234,11 +234,15 @@ extension FileTranslator {
     ) -> SchemaContent? {
         if contentKey.isJSON {
             let contentType = ContentType(contentKey.typeAndSubtype)
-            diagnostics.emitUnsupportedIfNotNil(
-                contentValue.encoding,
-                "Custom encoding for JSON content",
-                foundIn: "\(foundIn), content \(contentKey.rawValue)"
-            )
+            if contentType.lowercasedType == "multipart"
+                || contentType.lowercasedTypeAndSubtype.contains("application/x-www-form-urlencoded")
+            {
+                diagnostics.emitUnsupportedIfNotNil(
+                    contentValue.encoding,
+                    "Custom encoding for multipart/formEncoded content",
+                    foundIn: "\(foundIn), content \(contentType.originallyCasedTypeAndSubtype)"
+                )
+            }
             return .init(
                 contentType: contentType,
                 schema: contentValue.schema

Sources/_OpenAPIGeneratorCore/Translator/Content/ContentType.swift

@@ -70,7 +70,7 @@ struct ContentType: Hashable {
             case .json:
                 return .json
             case .text:
-                return .text
+                return .string
             case .binary:
                 return .binary
             }

Sources/_OpenAPIGeneratorCore/Translator/Parameters/TypedParameter.swift

@@ -158,23 +158,23 @@ extension FileTranslator {
             schema = schemaContext.schema
             style = schemaContext.style
             explode = schemaContext.explode
-            codingStrategy = .text
+            codingStrategy = .uri
 
             // Check supported exploded/style types
             let location = parameter.location
             switch location {
             case .query:
-                guard case .form = schemaContext.style else {
+                guard case .form = style else {
                     diagnostics.emitUnsupported(
-                        "Non-form style query params",
+                        "Query params of style \(style.rawValue), explode: \(explode)",
                         foundIn: foundIn
                     )
                     return nil
                 }
             case .header, .path:
-                guard case .simple = schemaContext.style else {
+                guard case .simple = style else {
                     diagnostics.emitUnsupported(
-                        "Non-simple style \(location.rawValue) params",
+                        "\(location.rawValue) params of style \(style.rawValue), explode: \(explode)",
                         foundIn: foundIn
                     )
                     return nil

Sources/_OpenAPIGeneratorCore/Translator/Parameters/translateParameter.swift

@@ -207,7 +207,7 @@ extension ServerFileTranslator {
             convertExpr = .try(
                 .identifier("converter").dot(methodName("QueryItem"))
                     .call([
-                        .init(label: "in", expression: .identifier("metadata").dot("queryParameters")),
+                        .init(label: "in", expression: .identifier("request").dot("query")),
                         .init(label: "style", expression: .dot(typedParameter.style.runtimeName)),
                         .init(label: "explode", expression: .literal(.bool(typedParameter.explode))),
                         .init(label: "name", expression: .literal(parameter.name)),

Sources/_OpenAPIGeneratorCore/Translator/Responses/TypedResponseHeader.swift

@@ -113,7 +113,7 @@ extension FileTranslator {
         switch header.schemaOrContent {
         case let .a(schemaContext):
             schema = schemaContext.schema
-            codingStrategy = .text
+            codingStrategy = .uri
         case let .b(contentMap):
             guard
                 let typedContent = try bestSingleTypedContent(

Sources/swift-openapi-generator/Documentation.docc/Articles/Supported-OpenAPI-features.md

@@ -210,21 +210,22 @@ Supported features are always provided on _both_ client and server.
 
 - [ ] matrix (in path)
 - [ ] label (in path)
-- [ ] form (in query)
-    - [x] primitive
-    - [x] array
-    - [ ] object
+- [x] form (in query)
 - [ ] form (in cookie)
 - [x] simple (in path)
 - [x] simple (in header)
 - [ ] spaceDelimited (in query)
 - [ ] pipeDelimited (in query)
 - [ ] deepObject (in query)
 
-Supported location + styles + exploded combinations:
-- path + simple + false
-- query + form + true/false
-- header + simple + false
+#### Supported combinations
+
+| Location | Style | Explode |
+| -------- | ----- | ------- |
+| path | `simple` | `false` |
+| query | `form` | `true` |
+| query | `form` | `false` |
+| header | `simple` | `false` |
 
 #### Reference Object