fix: exclude positionals from default completion

lib/completion.ts

@@ -105,13 +105,20 @@ export class Completion implements CompletionInstance {
   ) {
     if (current.match(/^-/) || (current === '' && completions.length === 0)) {
       const options = this.yargs.getOptions();
+      const positionalKeys =
+        this.yargs.getGroups()[this.usage.getPositionalGroupName()] || [];
+
       Object.keys(options.key).forEach(key => {
         const negable =
           !!options.configuration['boolean-negation'] &&
           options.boolean.includes(key);
+        const isPositionalKey = positionalKeys.includes(key);
 
-        // If the key and its aliases aren't in 'args', add the key to 'completions'
-        if (!this.argsContainKey(args, argv, key, negable)) {
+        // If the key is not positional and its aliases aren't in 'args', add the key to 'completions'
+        if (
+          !isPositionalKey &&
+          !this.argsContainKey(args, argv, key, negable)
+        ) {
           this.completeOptionKey(key, completions, current);
           if (negable && !!options.default[key])
             this.completeOptionKey(`no-${key}`, completions, current);

test/completion.cjs

@@ -214,6 +214,29 @@ describe('Completion', () => {
       r.logs.should.include('--opt2');
     });
 
+    it('ignores positionals for the correct command', () => {
+      process.env.SHELL = '/bin/bash';
+      const r = checkUsage(
+        () =>
+          yargs(['./completion', '--get-yargs-completions', 'cmd', '--o'])
+            .help(false)
+            .version(false)
+            .command('cmd', 'command', subYargs => {
+              subYargs
+                .options({
+                  opt: {
+                    describe: 'option',
+                  },
+                })
+                .positional('pos-opt', {type: 'string'});
+            }).argv
+      );
+
+      r.logs.should.have.length(1);
+      r.logs.should.include('--opt');
+      r.logs.should.not.include('--pos-opt');
+    });
+
     it('does not complete hidden commands', () => {
       process.env.SHELL = '/bin/bash';
       const r = checkUsage(