Option parsing fixes:

1. If a flag has an unexpected suffix and is not supported by the current driver mode, diagnose it as an unsupported option instead of being available in another mode
2. Reject 'separate' options if they have an unexpected suffix

Author: owenv

Sources/SwiftOptions/OptionParsing.swift

@@ -76,11 +76,13 @@ extension OptionTable {
           index: index - 1, argument: argument)
       }
 
-      // Make sure this option is supported by the current driver kind.
-      guard option.isAccepted(by: driverKind) else {
-        throw OptionParseError.unsupportedOption(
-          index: index - 1, argument: argument, option: option,
-          currentDriverKind: driverKind)
+      let verifyOptionIsAcceptedByDriverKind = {
+        // Make sure this option is supported by the current driver kind.
+        guard option.isAccepted(by: driverKind) else {
+          throw OptionParseError.unsupportedOption(
+            index: index - 1, argument: argument, option: option,
+            currentDriverKind: driverKind)
+        }
       }
 
       // Translate the argument
@@ -90,6 +92,7 @@ extension OptionTable {
 
       case .commaJoined:
         // Comma-separated list of arguments follows the option spelling.
+        try verifyOptionIsAcceptedByDriverKind()
         let rest = argument.dropFirst(option.spelling.count)
         parsedOptions.addOption(
           option,
@@ -101,16 +104,19 @@ extension OptionTable {
           throw OptionParseError.unknownOption(
             index: index - 1, argument: argument)
         }
+        try verifyOptionIsAcceptedByDriverKind()
         parsedOptions.addOption(option, argument: .none)
 
       case .joined:
         // Argument text follows the option spelling.
+        try verifyOptionIsAcceptedByDriverKind()
         parsedOptions.addOption(
           option,
           argument: .single(String(argument.dropFirst(option.spelling.count))))
 
       case .joinedOrSeparate:
         // Argument text follows the option spelling.
+        try verifyOptionIsAcceptedByDriverKind()
         let arg = argument.dropFirst(option.spelling.count)
         if !arg.isEmpty {
           parsedOptions.addOption(option, argument: .single(String(arg)))
@@ -131,6 +137,12 @@ extension OptionTable {
         index = arguments.endIndex
 
       case .separate:
+        if argument != option.spelling {
+          throw OptionParseError.unknownOption(
+            index: index - 1, argument: argument)
+        }
+        try verifyOptionIsAcceptedByDriverKind()
+
         if index == arguments.endIndex {
           throw OptionParseError.missingArgument(
             index: index - 1, argument: argument)

Tests/SwiftOptionsTests/OptionParsingTests.swift

@@ -32,6 +32,15 @@ final class SwiftDriverTests: XCTestCase {
       XCTAssertEqual(error as? OptionParseError, .unknownOption(index: 0, argument: "-unrecognized"))
     }
 
+    // Ensure we check for an unexpected suffix on flags before checking if they are accepted by the current mode.
+    XCTAssertThrowsError(try options.parse(["-c-NOT"], for: .interactive)) { error in
+      XCTAssertEqual(error as? OptionParseError, .unknownOption(index: 0, argument: "-c-NOT"))
+    }
+
+    XCTAssertThrowsError(try options.parse(["-module-name-NOT", "foo"], for: .batch)) { error in
+      XCTAssertEqual(error as? OptionParseError, .unknownOption(index: 0, argument: "-module-name-NOT"))
+    }
+
     XCTAssertThrowsError(try options.parse(["-I"], for: .batch)) { error in
       XCTAssertEqual(error as? OptionParseError, .missingArgument(index: 0, argument: "-I"))
     }