Decode + as a space in query items

Sources/OpenAPIRuntime/Conversion/Converter+Server.swift

@@ -139,7 +139,7 @@ extension Converter {
                     configuration: .init(
                         style: .init(style),
                         explode: explode,
-                        spaceEscapingCharacter: .percentEncoded,
+                        spaceEscapingCharacter: .plus,
                         dateTranscoder: configuration.dateTranscoder
                     )
                 )
@@ -177,7 +177,7 @@ extension Converter {
                     configuration: .init(
                         style: .init(style),
                         explode: explode,
-                        spaceEscapingCharacter: .percentEncoded,
+                        spaceEscapingCharacter: .plus,
                         dateTranscoder: configuration.dateTranscoder
                     )
                 )

Sources/OpenAPIRuntime/Conversion/CurrencyExtensions.swift

@@ -296,7 +296,14 @@ extension Converter {
     /// - Returns: The decoded value, or `nil` if the query item isn't present.
     /// - Throws: An error if decoding the query item or the JSON value fails.
     func convertJSONQueryItemToCodable<T: Decodable>(_ query: Substring, name: String) throws -> T? {
-        let uriDecoder = URIDecoder(configuration: uriCoderConfiguration(style: .form, explode: true, inBody: false))
+        let uriDecoder = URIDecoder(
+            configuration: .init(
+                style: .form,
+                explode: true,
+                spaceEscapingCharacter: .plus,
+                dateTranscoder: configuration.dateTranscoder
+            )
+        )
         guard let json = try uriDecoder.decodeIfPresent(String.self, forKey: name, from: query) else { return nil }
         return try decoder.decode(T.self, from: Data(json.utf8))
     }

Sources/OpenAPIRuntime/Interface/QuerySpaceNormalizingMiddleware.swift

@@ -18,13 +18,16 @@ public import HTTPTypes
 /// query string to `%20`, so that requests from clients that use
 /// `application/x-www-form-urlencoded` conventions decode correctly.
 ///
+/// - Important: Deprecated. The server now decodes `+` as a space in query
+///   items, so this middleware is no longer needed and can be removed.
+///
 /// The OpenAPI specification follows RFC 3986, which requires spaces in query
 /// strings to be percent-encoded as `%20`. However, many widely-used HTTP
 /// client libraries — including Python's `requests`, Java's `URLEncoder`,
 /// Scala's `sttp`, and JavaScript's `URLSearchParams` — encode spaces as `+`,
-/// following the `application/x-www-form-urlencoded` convention. Without this
-/// middleware, query parameters sent from such clients arrive at handlers with
-/// literal `+` characters instead of spaces.
+/// following the `application/x-www-form-urlencoded` convention. Previously,
+/// query parameters sent from such clients arrived at handlers with literal
+/// `+` characters instead of spaces.
 ///
 /// This middleware rewrites `+` to `%20` in the query portion of the request
 /// path before the request is parsed, so both encoding conventions produce the
@@ -41,6 +44,7 @@ public import HTTPTypes
 ///
 /// - Note: Only the query of the request is modified. The path, fragment, and
 ///   body are not touched.
+@available(*, deprecated, message: "`+` in query items is now decoded as a space by default; remove this middleware.")
 public struct QuerySpaceNormalizingMiddleware: ServerMiddleware {
     /// Creates a new middleware.
     public init() {}

Tests/OpenAPIRuntimeTests/Conversion/Test_Converter+Server.swift

@@ -186,6 +186,28 @@ final class Test_ServerConverterExtensions: Test_Runtime {
         XCTAssertEqual(value, "foo")
     }
 
+    func test_getOptionalQueryItemAsURI_string_plusAsSpace() throws {
+        let value: String? = try converter.getOptionalQueryItemAsURI(
+            in: "search=foo+bar%20baz%2Bqux",
+            style: nil,
+            explode: nil,
+            name: "search",
+            as: String.self
+        )
+        XCTAssertEqual(value, "foo bar baz+qux")
+    }
+
+    func test_getRequiredQueryItemAsURI_string_plusAsSpace() throws {
+        let value: String = try converter.getRequiredQueryItemAsURI(
+            in: "search=foo+bar%20baz%2Bqux",
+            style: nil,
+            explode: nil,
+            name: "search",
+            as: String.self
+        )
+        XCTAssertEqual(value, "foo bar baz+qux")
+    }
+
     func test_getOptionalQueryItemAsURI_arrayOfStrings() throws {
         let query: Substring = "search=foo&search=bar"
         let value: [String]? = try converter.getOptionalQueryItemAsURI(
@@ -234,6 +256,18 @@ final class Test_ServerConverterExtensions: Test_Runtime {
         XCTAssertEqual(value, ["foo", "bar"])
     }
 
+    func test_getRequiredQueryItemAsURI_arrayOfStrings_plusAsSpace() throws {
+        let query: Substring = "search=foo+bar&search=baz%2Bqux"
+        let value: [String] = try converter.getRequiredQueryItemAsURI(
+            in: query,
+            style: nil,
+            explode: nil,
+            name: "search",
+            as: [String].self
+        )
+        XCTAssertEqual(value, ["foo bar", "baz+qux"])
+    }
+
     func test_getRequiredQueryItemAsURI_arrayOfStrings_unexploded() throws {
         let query: Substring = "search=foo,bar"
         let value: [String] = try converter.getRequiredQueryItemAsURI(
@@ -298,6 +332,17 @@ final class Test_ServerConverterExtensions: Test_Runtime {
         XCTAssertEqual(value, [Filter(id: 1, name: "a/b")])
     }
 
+    func test_getRequiredQueryItemAsJSON_plusAsSpace() throws {
+        let value = try converter.getRequiredQueryItemAsJSON(
+            in: "filter=%22foo+bar%2Bbaz%22",
+            style: nil,
+            explode: nil,
+            name: "filter",
+            as: String.self
+        )
+        XCTAssertEqual(value, "foo bar+baz")
+    }
+
     func test_getOptionalQueryItemAsJSON_absent() throws {
         let value = try converter.getOptionalQueryItemAsJSON(
             in: "existing=1",

Tests/OpenAPIRuntimeTests/Interface/Test_QuerySpaceNormalizingMiddleware.swift

@@ -17,7 +17,7 @@ import HTTPTypes
 import XCTest
 @_spi(Generated) @testable import OpenAPIRuntime
 
-final class Test_QuerySpaceNormalizingMiddleware: XCTestCase {
+@available(*, deprecated) final class Test_QuerySpaceNormalizingMiddleware: XCTestCase {
     static let middleware = QuerySpaceNormalizingMiddleware()
 
     func testPlusInQueryIsReplacedWithPercent20() async throws {