fixed issue with flags parsed twice on multiflags.

Author: dastrobu

Sources/parsers/MultiFlag.swift

@@ -47,7 +47,14 @@ public class MultiFlag: Parser, ParserNode, ParsePathSegment {
                 return 1
             }
         }
-        return try parseTree(arguments: arguments, atIndex: i, path: path + [self], childParsers: parsers)
+        // parse flag normally
+        for parser in parsers {
+            let tokensConsumed = try parser.parse(arguments: arguments, atIndex: i, path: path + [self])
+            if tokensConsumed > 0 {
+                return tokensConsumed
+            }
+        }
+        return 0
     }
 
     public var description: [(argument: String, description: String)] {

Tests/argtreeTests/parsers/MultiFlagTests.swift

@@ -6,7 +6,7 @@ final class MultiFlagTests: XCTestCase {
     func testFlagParsing() {
         var xPath: [ParsePathSegment] = []
         var yPath: [ParsePathSegment] = []
-        let tokensConsumed = try? ArgTree(parsers: [
+        let tokensConsumed = try! ArgTree(parsers: [
             MultiFlag(parsers: [
                 Flag(shortName: "x", parsed: { path in
                     xPath = path
@@ -22,6 +22,21 @@ final class MultiFlagTests: XCTestCase {
         XCTAssertEqual(yPath.count, 1, "yPath \(yPath)")
     }
 
+    func testFlagParsingWithOneFlag() {
+        var xPath: [ParsePathSegment] = []
+        let tokensConsumed = try! ArgTree(parsers: [
+            MultiFlag(parsers: [
+                Flag(shortName: "x", parsed: { path in
+                    xPath = path
+                }),
+            ]),
+            VarArgs(),
+        ]).parse(arguments: ["ignored", "foo", "-x"])
+
+        XCTAssertEqual(tokensConsumed, 3)
+        XCTAssertEqual(xPath.count, 1, "xPath \(xPath)")
+    }
+
     func testFlagParsingStopToken() {
         var xPath: [ParsePathSegment] = []
         var yPath: [ParsePathSegment] = []