Use variadic generics in Swift 5.9

Sources/PostgresNIO/New/PostgresRow-multi-decode.swift

@@ -1,5 +1,6 @@
 /// NOTE: THIS FILE IS AUTO-GENERATED BY dev/generate-postgresrow-multi-decode.sh
 
+#if compiler(<5.9)
 extension PostgresRow {
     @inlinable
     @_alwaysEmitIntoClient
@@ -1171,3 +1172,4 @@ extension PostgresRow {
         try self.decode((T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14).self, context: .default, file: file, line: line)
     }
 }
+#endif

Sources/PostgresNIO/New/PostgresRowSequence-multi-decode.swift

@@ -1,6 +1,6 @@
 /// NOTE: THIS FILE IS AUTO-GENERATED BY dev/generate-postgresrowsequence-multi-decode.sh
 
-#if canImport(_Concurrency)
+#if compiler(<5.9)
 extension AsyncSequence where Element == PostgresRow {
     @inlinable
     @_alwaysEmitIntoClient

Sources/PostgresNIO/New/VariadicGenerics.swift

@@ -0,0 +1,174 @@
+#if compiler(>=5.9)
+extension PostgresRow {
+    // --- snip TODO: Remove once bug is fixed, that disallows tuples of one
+    @inlinable
+    public func decode<Column: PostgresDecodable>(
+        _: Column.Type,
+        file: String = #fileID,
+        line: Int = #line
+    ) throws -> (Column) {
+        try self.decode(Column.self, context: .default, file: file, line: line)
+    }
+
+    @inlinable
+    public func decode<Column: PostgresDecodable>(
+        _: Column.Type,
+        context: PostgresDecodingContext<some PostgresJSONDecoder>,
+        file: String = #fileID,
+        line: Int = #line
+    ) throws -> (Column) {
+        precondition(self.columns.count >= 1)
+        let columnIndex = 0
+        var cellIterator = self.data.makeIterator()
+        var cellData = cellIterator.next().unsafelyUnwrapped
+        var columnIterator = self.columns.makeIterator()
+        let column = columnIterator.next().unsafelyUnwrapped
+        let swiftTargetType: Any.Type = Column.self
+
+        do {
+            let r0 = try Column._decodeRaw(from: &cellData, type: column.dataType, format: column.format, context: context)
+
+            return (r0)
+        } catch let code as PostgresDecodingError.Code {
+            throw PostgresDecodingError(
+                code: code,
+                columnName: column.name,
+                columnIndex: columnIndex,
+                targetType: swiftTargetType,
+                postgresType: column.dataType,
+                postgresFormat: column.format,
+                postgresData: cellData,
+                file: file,
+                line: line
+            )
+        }
+    }
+    // --- snap TODO: Remove once bug is fixed, that disallows tuples of one
+
+    @inlinable
+    public func decode<each Column: PostgresDecodable>(
+        _ columnType: (repeat each Column).Type,
+        context: PostgresDecodingContext<some PostgresJSONDecoder>,
+        file: String = #fileID,
+        line: Int = #line
+    ) throws -> (repeat each Column) {
+        let packCount = ComputeParameterPackLength.count(ofPack: repeat (each Column).self)
+        precondition(self.columns.count >= packCount)
+
+        var columnIndex = 0
+        var cellIterator = self.data.makeIterator()
+        var columnIterator = self.columns.makeIterator()
+
+        return (
+            repeat try Self.decodeNextColumn(
+                (each Column).self,
+                cellIterator: &cellIterator,
+                columnIterator: &columnIterator,
+                columnIndex: &columnIndex,
+                context: context,
+                file: file,
+                line: line
+            )
+        )
+    }
+
+    @inlinable
+    static func decodeNextColumn<Column: PostgresDecodable>(
+        _ columnType: Column.Type,
+        cellIterator: inout IndexingIterator<DataRow>,
+        columnIterator: inout IndexingIterator<[RowDescription.Column]>,
+        columnIndex: inout Int,
+        context: PostgresDecodingContext<some PostgresJSONDecoder>,
+        file: String,
+        line: Int
+    ) throws -> Column {
+        defer { columnIndex += 1 }
+
+        let column = columnIterator.next().unsafelyUnwrapped
+        var cellData = cellIterator.next().unsafelyUnwrapped
+        do {
+            return try Column._decodeRaw(from: &cellData, type: column.dataType, format: column.format, context: context)
+        } catch let code as PostgresDecodingError.Code {
+            throw PostgresDecodingError(
+                code: code,
+                columnName: column.name,
+                columnIndex: columnIndex,
+                targetType: Column.self,
+                postgresType: column.dataType,
+                postgresFormat: column.format,
+                postgresData: cellData,
+                file: file,
+                line: line
+            )
+        }
+    }
+
+    @inlinable
+    public func decode<each Column: PostgresDecodable>(
+        _ columnType: (repeat each Column).Type,
+        file: String = #fileID,
+        line: Int = #line
+    ) throws -> (repeat each Column) {
+        try self.decode(columnType, context: .default, file: file, line: line)
+    }
+}
+
+extension AsyncSequence where Element == PostgresRow {
+    // --- snip TODO: Remove once bug is fixed, that disallows tuples of one
+    @inlinable
+    public func decode<Column: PostgresDecodable>(
+        _: Column.Type,
+        context: PostgresDecodingContext<some PostgresJSONDecoder>,
+        file: String = #fileID,
+        line: Int = #line
+    ) -> AsyncThrowingMapSequence<Self, (Column)> {
+        self.map { row in
+            try row.decode(Column.self, context: context, file: file, line: line)
+        }
+    }
+
+    @inlinable
+    public func decode<Column: PostgresDecodable>(
+        _: Column.Type,
+        file: String = #fileID,
+        line: Int = #line
+    ) -> AsyncThrowingMapSequence<Self, (Column)> {
+        self.decode(Column.self, context: .default, file: file, line: line)
+    }
+    // --- snap TODO: Remove once bug is fixed, that disallows tuples of one
+
+    public func decode<each Column: PostgresDecodable>(
+        _ columnType: (repeat each Column).Type,
+        context: PostgresDecodingContext<some PostgresJSONDecoder>,
+        file: String = #fileID,
+        line: Int = #line
+    ) -> AsyncThrowingMapSequence<Self, (repeat each Column)> {
+        self.map { row in
+            try row.decode(columnType, context: context, file: file, line: line)
+        }
+    }
+
+    public func decode<each Column: PostgresDecodable>(
+        _ columnType: (repeat each Column).Type,
+        file: String = #fileID,
+        line: Int = #line
+    ) -> AsyncThrowingMapSequence<Self, (repeat each Column)> {
+        self.decode(columnType, context: .default, file: file, line: line)
+    }
+}
+
+@usableFromInline
+enum ComputeParameterPackLength {
+    @usableFromInline
+    enum BoolConverter<T> {
+        @usableFromInline
+        typealias Bool = Swift.Bool
+    }
+
+    @inlinable
+    static func count<each T>(ofPack t: repeat each T) -> Int {
+        MemoryLayout<(repeat BoolConverter<each T>.Bool)>.size / MemoryLayout<Bool>.stride
+    }
+}
+#endif // compiler(>=5.9)
+

Tests/IntegrationTests/AsyncTests.swift

@@ -8,7 +8,6 @@ import NIOPosix
 import NIOCore
 
 final class AsyncPostgresConnectionTests: XCTestCase {
-
     func test1kRoundTrips() async throws {
         let eventLoopGroup = MultiThreadedEventLoopGroup(numberOfThreads: 1)
         defer { XCTAssertNoThrow(try eventLoopGroup.syncShutdownGracefully()) }
@@ -37,7 +36,8 @@ final class AsyncPostgresConnectionTests: XCTestCase {
         try await withTestConnection(on: eventLoop) { connection in
             let rows = try await connection.query("SELECT generate_series(\(start), \(end));", logger: .psqlTest)
             var counter = 0
-            for try await element in rows.decode(Int.self, context: .default) {
+            for try await row in rows {
+                let element = try row.decode(Int.self)
                 XCTAssertEqual(element, counter + 1)
                 counter += 1
             }
@@ -259,7 +259,8 @@ final class AsyncPostgresConnectionTests: XCTestCase {
         try await withTestConnection(on: eventLoop) { connection in
             let rows = try await connection.query("SELECT generate_series(\(start), \(end));", logger: .psqlTest)
             var counter = 1
-            for try await element in rows.decode(Int.self, context: .default) {
+            for try await row in rows {
+                let element = try row.decode(Int.self, context: .default)
                 XCTAssertEqual(element, counter)
                 counter += 1
             }

Tests/IntegrationTests/PostgresNIOTests.swift

@@ -1246,10 +1246,10 @@ final class PostgresNIOTests: XCTestCase {
             return EventLoopFuture.whenAllSucceed([a, b, c], on: self.eventLoop)
         }).wait())
         XCTAssertEqual(queries?.count, 3)
-        var resutIterator = queries?.makeIterator()
-        XCTAssertEqual(try resutIterator?.next()?.first?.decode(String.self, context: .default), "a")
-        XCTAssertEqual(try resutIterator?.next()?.first?.decode(String.self, context: .default), "b")
-        XCTAssertEqual(try resutIterator?.next()?.first?.decode(String.self, context: .default), "c")
+        var resultIterator = queries?.makeIterator()
+        XCTAssertEqual(try resultIterator?.next()?.first?.decode(String.self, context: .default), "a")
+        XCTAssertEqual(try resultIterator?.next()?.first?.decode(String.self, context: .default), "b")
+        XCTAssertEqual(try resultIterator?.next()?.first?.decode(String.self, context: .default), "c")
     }
 
     // https://github.com/vapor/postgres-nio/issues/122

Tests/PostgresNIOTests/New/PostgresRowSequenceTests.swift

@@ -59,7 +59,7 @@ final class PostgresRowSequenceTests: XCTestCase {
 
         var counter = 0
         for try await row in rowSequence {
-            XCTAssertEqual(try row.decode(Int.self, context: .default), counter)
+            XCTAssertEqual(try row.decode(Int.self), counter)
             counter += 1
 
             if counter == 64 {
@@ -135,7 +135,7 @@ final class PostgresRowSequenceTests: XCTestCase {
 
         var counter = 0
         for try await row in rowSequence {
-            XCTAssertEqual(try row.decode(Int.self, context: .default), counter)
+            XCTAssertEqual(try row.decode(Int.self), counter)
             counter += 1
         }
 
@@ -163,7 +163,7 @@ final class PostgresRowSequenceTests: XCTestCase {
 
         var counter = 0
         for try await row in rowSequence {
-            XCTAssertEqual(try row.decode(Int.self, context: .default), counter)
+            XCTAssertEqual(try row.decode(Int.self), counter)
             counter += 1
         }
 
@@ -220,7 +220,7 @@ final class PostgresRowSequenceTests: XCTestCase {
         }
 
         let row1 = try await rowIterator.next()
-        XCTAssertEqual(try row1?.decode(Int.self, context: .default), 0)
+        XCTAssertEqual(try row1?.decode(Int.self), 0)
 
         DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(1)) {
             stream.receive(completion: .success("SELECT 1"))
@@ -252,7 +252,7 @@ final class PostgresRowSequenceTests: XCTestCase {
         }
 
         let row1 = try await rowIterator.next()
-        XCTAssertEqual(try row1?.decode(Int.self, context: .default), 0)
+        XCTAssertEqual(try row1?.decode(Int.self), 0)
 
         DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(1)) {
             stream.receive(completion: .failure(PSQLError.serverClosedConnection(underlying: nil)))
@@ -415,7 +415,7 @@ final class PostgresRowSequenceTests: XCTestCase {
         var counter = 1
         for _ in 0..<(2 * messagePerChunk - 1) {
             let row = try await rowIterator.next()
-            XCTAssertEqual(try row?.decode(Int.self, context: .default), counter)
+            XCTAssertEqual(try row?.decode(Int.self), counter)
             counter += 1
         }