Fix parsing for single-dash names with .upToNextOption parsing

Sources/ArgumentParser/Parsing/ArgumentSet.swift

@@ -221,6 +221,7 @@ extension ArgumentSet {
         if let value = parsed.value {
           // This was `--foo=bar` style:
           try update(origin, parsed.name, value, &result)
+          usedOrigins.formUnion(origin)
         } else if argument.allowsJoinedValue,
            let (origin2, value) = inputArguments.extractJoinedElement(at: originElement)
         {
@@ -243,6 +244,7 @@ extension ArgumentSet {
         if let value = parsed.value {
           // This was `--foo=bar` style:
           try update(origin, parsed.name, value, &result)
+          usedOrigins.formUnion(origin)
         } else if argument.allowsJoinedValue,
             let (origin2, value) = inputArguments.extractJoinedElement(at: originElement) {
           // Found a joined argument
@@ -320,6 +322,11 @@ extension ArgumentSet {
           inputArguments.removeAll(in: usedOrigins)
         }
 
+        // Clear out the initial origin first, since it can include
+        // the exploded elements of an options group (see issue #327).
+        usedOrigins.formUnion(origin)
+        inputArguments.removeAll(in: origin)
+
         // ...and then consume the arguments until hitting an option
         while let (origin2, value) = inputArguments.popNextElementIfValue() {
           let origins = origin.inserting(origin2)

Tests/ArgumentParserEndToEndTests/LongNameWithShortDashEndToEndTests.swift

@@ -107,3 +107,28 @@ extension LongNameWithSingleDashEndToEndTests {
     XCTAssertThrowsError(try Bar.parse(["--file"]))
   }
 }
+
+extension LongNameWithSingleDashEndToEndTests {
+  private struct Issue327: ParsableCommand {
+    @Option(name: .customLong("argWithAnH", withSingleDash: true),
+            parsing: .upToNextOption)
+    var args: [String]
+  }
+
+  func testIssue327() {
+    AssertParse(Issue327.self, ["-argWithAnH", "03ade86c0", "8f2058e3ade86c84ec5b"]) { issue327 in
+      XCTAssertEqual(issue327.args, ["03ade86c0", "8f2058e3ade86c84ec5b"])
+    }
+  }
+
+  private struct JoinedItem: ParsableCommand {
+    @Option(name: .customLong("argWithAnH", withSingleDash: true))
+    var arg: String
+  }
+
+  func testJoinedItem_Issue327() {
+    AssertParse(JoinedItem.self, ["-argWithAnH=foo"]) { joinedItem in
+      XCTAssertEqual(joinedItem.arg, "foo")
+    }
+  }
+}