bug#24365: 24.4; [PATCH] url-http-options fails when connection refused

[Noam Postavsky]

found 24365 25.3
quit

Mark Schreiber <mark7@alumni.cmu.edu> writes:

> url-http-options fails when a web server refuses its connection.
>
> Evaluating (url-http-options "http://127.0.0.1:33333/";) results in the
> following error:
>
> Debugger entered--Lisp error: (wrong-type-argument number-or-marker-p nil)
>   url-http-options("http://127.0.0.1:33333/";)

In emacs-26, I get a "Connection refused" error, which seems reasonable.

Debugger entered--Lisp error: (file-error "make client process failed" 
"Connection refused" :name "127.0.0.1" :buffer #<buffer  *url-http-temp*> :host 
"127.0.0.1" :service 33333 :nowait nil :tls-parameters nil)
  make-network-process(:name "127.0.0.1" :buffer #<buffer  *url-http-temp*> 
:host "127.0.0.1" :service 33333 :nowait nil :tls-parameters nil)
  open-network-stream("127.0.0.1" #<buffer  *url-http-temp*> "127.0.0.1" 33333 
:type plain :nowait nil)
  url-open-stream("127.0.0.1" #<buffer  *url-http-temp*> "127.0.0.1" 33333 nil)
  url-http-find-free-connection("127.0.0.1" 33333 nil)
  url-http(#s(url :type "http" :user nil :password nil :host "127.0.0.1" 
:portspec 33333 :filename "/" :target nil :attributes nil :fullness t :silent 
nil :use-cookies t :asynchronous nil) #f(compiled-function (&rest ignored) 
#<bytecode 0x5a532d>) (nil))
  url-retrieve-internal("http://127.0.0.1:33333/"; #f(compiled-function (&rest 
ignored) #<bytecode 0x5a532d>) (nil) nil nil)
  url-retrieve("http://127.0.0.1:33333/"; #f(compiled-function (&rest ignored) 
#<bytecode 0x5a532d>) nil nil nil)
  url-retrieve-synchronously("http://127.0.0.1:33333/";)
  url-http-options("http://127.0.0.1:33333/";)

> In my case, this caused the third-party package org-caldav to fail with
> this error when M-x org-caldav-sync was invoked and given an incorrect
> org-caldav-url.
>
> I believe that the correct behavior would be to have url-http-options
> return nil, which is the behavior of that function when it receives an
> HTTP error response.

The error which is thrown in emacs-26 would make it clear that you need
to correct the url, so I think we should leave it as is.