fix: positionals should not overwrite options

lib/command.ts

@@ -598,7 +598,18 @@ export class CommandInstance {
           // any new aliases need to be placed in positionalMap, which
           // is used for validation.
           if (!positionalMap[key]) positionalMap[key] = parsed.argv[key];
-          argv[key] = parsed.argv[key];
+          // Addresses: https://github.com/yargs/yargs/issues/1637
+          // If both positionals/options provided,
+          // and if at least one is an array: don't overwrite, combine.
+          if (
+            Object.prototype.hasOwnProperty.call(argv, key) &&
+            Object.prototype.hasOwnProperty.call(parsed.argv, key) &&
+            (Array.isArray(argv[key]) || Array.isArray(parsed.argv[key]))
+          ) {
+            argv[key] = ([] as string[]).concat(argv[key], parsed.argv[key]);
+          } else {
+            argv[key] = parsed.argv[key];
+          }
         }
       });
     }

lib/yargs-factory.ts

@@ -809,7 +809,7 @@ export class YargsInstance {
       );
     } else {
       globals.forEach(g => {
-        if (this.#options.local.indexOf(g) === -1) this.#options.local.push(g);
+        if (!this.#options.local.includes(g)) this.#options.local.push(g);
       });
     }
     return this;

test/command.cjs

@@ -209,6 +209,58 @@ describe('Command', () => {
       argv['--'].should.eql(['apple', 'banana']);
       called.should.equal(true);
     });
+
+    // Addresses: https://github.com/yargs/yargs/issues/1637
+    it('does not overwrite options in argv if variadic', () => {
+      yargs
+        .command({
+          command: 'cmd [foods..]',
+          desc: 'cmd desc',
+          builder: yargs =>
+            yargs.positional('foods', {
+              desc: 'foods desc',
+              type: 'string',
+            }),
+          handler: argv => {
+            argv.foods.should.deep.equal(['apples', 'cherries', 'grapes']);
+          },
+        })
+        .parse('cmd --foods apples cherries grapes');
+    });
+
+    it('does not overwrite options in argv if variadic and when using default command', () => {
+      yargs
+        .command({
+          command: '$0 [foods..]',
+          desc: 'default desc',
+          builder: yargs =>
+            yargs.positional('foods', {
+              desc: 'foods desc',
+              type: 'string',
+            }),
+          handler: argv => {
+            argv.foods.should.deep.equal(['apples', 'cherries', 'grapes']);
+          },
+        })
+        .parse('--foods apples cherries grapes');
+    });
+
+    it('does not overwrite options in argv if variadic and preserves falsey values', () => {
+      yargs
+        .command({
+          command: '$0 [numbers..]',
+          desc: 'default desc',
+          builder: yargs =>
+            yargs.positional('numbers', {
+              desc: 'numbers desc',
+              type: 'number',
+            }),
+          handler: argv => {
+            argv.numbers.should.deep.equal([0, 1, 2]);
+          },
+        })
+        .parse('--numbers 0 1 2');
+    });
   });
 
   describe('variadic', () => {