[wp-trac] [WordPress Trac] #64635: IXR_Client: Undefined array key "host" when parse_url returns no host

[WordPress Trac]

#64635: IXR_Client: Undefined array key "host" when parse_url returns no host
--------------------------+-----------------------------
 Reporter:  bluefuton     |      Owner:  (none)
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  XML-RPC       |    Version:  trunk
 Severity:  trivial       |   Keywords:
  Focuses:                |
--------------------------+-----------------------------
 `IXR_Client::__construct()` in `wp-includes/IXR/class-IXR-client.php`
 accesses `$bits['host']` on line 33 without a key existence check after
 calling `parse_url()`. This triggers an "Undefined array key" warning when
 the URL passed has no host (e.g. a relative path like `/xmlrpc.php`).

 Lines 34-35 already guard against missing keys for `port` and `path`:

   {{{#!php
   $bits = parse_url($server);
   $this->server = $bits['host'];  // <- unguarded
   $this->port = $bits['port'] ?? 80;
   $this->path = $bits['path'] ?? '/';
   }}}

 To improve resilience, we could apply the same pattern to `host`:

   {{{#!php
   $this->server = $bits['host'] ?? '';
   }}}

   '''How to reproduce:''' Pass a relative URL (no scheme/host) as the
 `$server` parameter to `IXR_Client` with `$path = false`. For example,
 this occurs in Jetpack when `Jetpack_IXR_Client` constructs an
 `IXR_Client` and `JETPACK__API_BASE` is undefined.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/64635>
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