Remove the dependency on libreadline

It was only active on macOS and Linux but not other platforms due to existing dependency complexities, and just isn't that useful overall. This will help unblock swiftlang/swift-package-manager#8271 without having to add new dependencies to the Swift Docker images.

Author: jakepetroules

Package.swift

@@ -22,7 +22,6 @@ let appleOS = false
 
 let useLocalDependencies = Context.environment["SWIFTCI_USE_LOCAL_DEPS"] != nil
 let useLLBuildFramework = Context.environment["SWIFTBUILD_LLBUILD_FWK"] != nil
-let readlinePackage = !appleOS ? "readline" : nil
 
 let swiftSettings: [SwiftSetting] = [
     // Upcoming Swift 6.0 features
@@ -162,7 +161,6 @@ let package = Package(
             dependencies: [
                 "SWBCSupport",
                 "SWBLibc",
-                .target(name: "readline", condition: .when(platforms: [.linux])),
                 .product(name: "ArgumentParser", package: "swift-argument-parser"),
                 .product(name: "Crypto", package: "swift-crypto", condition: .when(platforms: [.linux, .android])),
                 .product(name: "SystemPackage", package: "swift-system", condition: .when(platforms: [.linux, .android, .windows])),
@@ -343,17 +341,6 @@ let package = Package(
             dependencies: ["SwiftBuild", "SWBTestSupport", "SwiftBuildTestSupport"],
             swiftSettings: swiftSettings),
 
-        // System libraries
-        .systemLibrary(
-            name: "readline",
-            path: "Packages/Sources/readline",
-            pkgConfig: readlinePackage,
-            providers: [
-                .apt(["libreadline-dev"]),
-                .yum(["readline-devel"]),
-            ]
-        ),
-
         // Commands
         .plugin(
             name: "launch-xcode",

Packages/.gitignore

@@ -19,15 +19,6 @@
 #include <TargetConditionals.h>
 #endif
 
-#ifndef __APPLE__
-// Re-exported from readline
-char *readline(const char *);
-int add_history(const char *);
-int read_history(const char *);
-int write_history(const char *);
-int history_truncate_file(const char *, int);
-#endif
-
 #include "CLibclang.h"
 #include "CLibRemarksHelper.h"
 #include "PluginAPI.h"

Packages/Sources/readline/module.modulemap

@@ -15,27 +15,19 @@ import SWBUtil
 
 import Foundation
 
-let kHistoryFilePath = "~/.swbuild_history"
-let kMaxHistoryLines = 100
-
 func swbuild_handle_command_result(result: SWBServiceConsoleResult)  {
     print(result.output, terminator: "")
 }
 
 /// Process a command line.
 ///
 /// - returns: True if the console should continue handling commands, otherwise the console should quit.
-func swbuild_process_command(console: SWBBuildServiceConsole, command: String, historyPath: String) async -> (shouldContinue: Bool, success: Bool) {
+func swbuild_process_command(console: SWBBuildServiceConsole, command: String) async -> (shouldContinue: Bool, success: Bool) {
     // Ignore empty commands.
     if command.isEmpty {
         return (true, true)
     }
 
-    // Add the line to the history.
-    swb_add_history(command)
-    swb_write_history(historyPath)
-    swb_history_truncate_file(historyPath, kMaxHistoryLines)
-
     // Process the line.
     let (result, success) = await console.sendCommandString(command)
     swbuild_handle_command_result(result: result)
@@ -71,24 +63,20 @@ func swbuild_repl() async throws -> Bool {
     // Save the terminal attributes (and restore them and exit).
     return try await withTerminalAttributes { terminalAttributes in
         return try await withServiceConsole { console in
-            let historyPath = (kHistoryFilePath as NSString).expandingTildeInPath
-
-            // Read in the command history.
-            swb_read_history(historyPath)
-
             // Disable echo, after all readline initialization is done.
             terminalAttributes.disableEcho()
 
             var ok = true
             var shouldContinue = true
             while shouldContinue {
-                guard let line = swb_readline("swbuild> ") else {
+                print("swbuild> ", terminator: "")
+                guard let line = readLine() else {
                     // If we received the EOF then exit.
                     print()
                     break
                 }
 
-                (shouldContinue, ok) = await swbuild_process_command(console: console, command: line, historyPath: historyPath)
+                (shouldContinue, ok) = await swbuild_process_command(console: console, command: line)
             }
 
             return ok