fix: replace bare assert with graceful handler in _guess_method (#1614)

httpie/cli/argparser.py

@@ -413,7 +413,16 @@ def _guess_method(self):
         """
         if self.args.method is None:
             # Invoked as `http URL'.
-            assert not self.args.request_items
+            if self.args.request_items and self.args.url is None:
+        # Promote what argparse put in request_items[0] as the URL.
+                self.args.url = self.args.request_items.pop(0)
+            elif self.args.request_items:
+        # url is already set AND request_items is non-empty: genuine error.
+                self.error(
+            "Could not determine the request URL. "
+            "Make sure the URL comes directly after the HTTP method:\n"
+            f"  http {self.args.method} URL [REQUEST_ITEM ...]"
+        )
             if self.has_input_data:
                 self.args.method = HTTP_POST
             else:

tests/test_cli.py

@@ -315,6 +315,24 @@ def test_guess_when_method_set_but_invalid_and_item_exists(self):
             KeyValueArg(
                 key='old_item', value='b', sep='=', orig='old_item=b'),
         ]
+
+    def test_guess_when_method_set_and_url_in_request_items(self):
+        """Regression test for https://github.com/httpie/cli/issues/1614.
+        When optional flags appear between METHOD and URL, argparse can
+        land the URL in request_items. _guess_method should recover gracefully.
+        """
+        self.parser.args = argparse.Namespace()
+        self.parser.args.method = 'POST'
+        self.parser.args.url = None           # url not yet parsed
+        self.parser.args.request_items = ['https://example.org']  # URL ended up here
+        self.parser.args.ignore_stdin = False
+        self.parser.env = MockEnvironment()
+
+        self.parser._guess_method()
+
+        assert self.parser.args.method == 'POST'
+        assert self.parser.args.url == 'https://example.org'
+        assert self.parser.args.request_items == []
 
 
 class TestNoOptions: