check port in use and add itself

spacy/displacy/__init__.py

@@ -11,7 +11,7 @@ from .render import DependencyRenderer, EntityRenderer, SpanRenderer
 from ..tokens import Doc, Span
 from ..errors import Errors, Warnings
 from ..util import is_in_jupyter
-
+from ..util import is_port_in_use
 
 _html = {}
 RENDER_WRAPPER = None
@@ -99,9 +99,15 @@ def serve(
     """
     from wsgiref import simple_server
 
+    if is_port_in_use(port):
+        port += 1
+        while is_port_in_use(port) and port < 65535:
+            port += 1
+
     if is_in_jupyter():
         warnings.warn(Warnings.W011)
     render(docs, style=style, page=page, minify=minify, options=options, manual=manual)
+
     httpd = simple_server.make_server(host, port, app)
     print(f"\nUsing the '{style}' visualizer")
     print(f"Serving on http://{host}:{port} ...\n")

spacy/util.py

@@ -31,7 +31,7 @@ import shlex
 import inspect
 import pkgutil
 import logging
-
+import socket
 try:
     import cupy.random
 except ImportError:
@@ -1736,3 +1736,8 @@ def all_equal(iterable):
     (or if the input is an empty sequence), False otherwise."""
     g = itertools.groupby(iterable)
     return next(g, True) and not next(g, False)
+
+
+def is_port_in_use(port):
+    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
+        return s.connect_ex(('localhost', port)) == 0