Potenially fix quoted string completion

worldedit-core/src/main/java/com/sk89q/worldedit/extension/platform/PlatformCommandManager.java

@@ -431,7 +431,7 @@ public final class PlatformCommandManager {
     }
 
     private Stream<Substring> parseArgs(String input) {
-        return new CommandArgParser(CommandArgParser.spaceSplit(input.substring(1))).parseArgs();
+        return CommandArgParser.forArgString(input.substring(1)).parseArgs();
     }
 
     @Subscribe

worldedit-core/src/main/java/com/sk89q/worldedit/internal/command/CommandArgParser.java

@@ -31,6 +31,10 @@ import java.util.stream.Stream;
 
 public class CommandArgParser {
 
+    public static CommandArgParser forArgString(String argString) {
+        return new CommandArgParser(spaceSplit(argString));
+    }
+
     public static ImmutableList<Substring> spaceSplit(String string) {
         ImmutableList.Builder<Substring> result = ImmutableList.builder();
         int index = 0;
@@ -79,14 +83,14 @@ public class CommandArgParser {
             if (strPart.endsWith("\"") && strPart.length() > 1) {
                 currentArg.add(Substring.wrap(
                         strPart.substring(1, strPart.length() - 1),
-                        part.getStart(), part.getEnd()
+                        part.getStart() + 1, part.getEnd() - 1
                 ));
                 finishArg();
             } else {
                 state = State.QUOTE;
                 currentArg.add(Substring.wrap(
                         strPart.substring(1),
-                        part.getStart(), part.getEnd()
+                        part.getStart() + 1, part.getEnd()
                 ));
             }
         } else {
@@ -100,7 +104,7 @@ public class CommandArgParser {
             state = State.NORMAL;
             currentArg.add(Substring.wrap(
                 part.getSubstring().substring(0, part.getSubstring().length() - 1),
-                part.getStart(), part.getEnd()
+                part.getStart(), part.getEnd() - 1
             ));
             finishArg();
         } else {

worldedit-core/src/main/java/com/sk89q/worldedit/internal/command/CommandUtil.java

@@ -21,6 +21,7 @@ package com.sk89q.worldedit.internal.command;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
+import com.google.common.collect.Iterators;
 import com.sk89q.worldedit.extension.platform.PlatformCommandManager;
 import com.sk89q.worldedit.internal.util.Substring;
 import com.sk89q.worldedit.util.formatting.text.Component;
@@ -65,7 +66,9 @@ public class CommandUtil {
      * Fix {@code suggestions} to replace the last space-separated word in {@code arguments}.
      */
     public static List<String> fixSuggestions(String arguments, List<Substring> suggestions) {
-        Substring lastArg = Iterables.getLast(CommandArgParser.spaceSplit(arguments));
+        Substring lastArg = Iterables.getLast(
+            CommandArgParser.spaceSplit(arguments)
+        );
         return suggestions.stream()
             .map(suggestion -> CommandUtil.suggestLast(lastArg, suggestion))
             .filter(Optional::isPresent)

worldedit-core/src/test/java/com/sk89q/worldedit/internal/command/CommandArgParserTest.java

@@ -23,29 +23,36 @@ import com.google.common.collect.ImmutableList;
 import com.sk89q.worldedit.internal.util.Substring;
 import org.junit.jupiter.api.Test;
 
-import static com.sk89q.worldedit.internal.command.CommandArgParser.spaceSplit;
+import java.util.List;
+import java.util.stream.Collectors;
+
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
-public class CommandArgParserTest {
+class CommandArgParserTest {
+
+    private static List<Substring> argParse(String s) {
+        return CommandArgParser.forArgString(s).parseArgs().collect(Collectors.toList());
+    }
+
     @Test
-    public void testSpaceSplit() {
+    void testArgumentParsing() {
         assertEquals(ImmutableList.of(
             Substring.wrap("", 0, 0)
-        ), spaceSplit(""));
+        ), argParse(""));
         assertEquals(ImmutableList.of(
             Substring.wrap("ab", 0, 2)
-        ), spaceSplit("ab"));
+        ), argParse("ab"));
         assertEquals(ImmutableList.of(
             Substring.wrap("", 0, 0),
             Substring.wrap("", 1, 1)
-        ), spaceSplit(" "));
+        ), argParse(" "));
         assertEquals(ImmutableList.of(
             Substring.wrap("a", 0, 1),
             Substring.wrap("", 2, 2)
-        ), spaceSplit("a "));
+        ), argParse("a "));
         assertEquals(ImmutableList.of(
             Substring.wrap("a", 0, 1),
             Substring.wrap("b", 2, 3)
-        ), spaceSplit("a b"));
+        ), argParse("a b"));
     }
 }