Debian 10.5 buster
MediaWiki 1.35.0-rc.2
PHP 7.3.19-1~deb10u1 (apache2handler)
MariaDB 10.4.8-MariaDB-log
When I try to create a page using Visual Editor that has either : or / in the title I get an error: **Error contacting the Parsoid/RESTBase server (HTTP 404)**
Debugging the warning emitted in file ApiParsoidTrait.php
(/extensions/VisualEditor/includes/ApiParsoidTrait.php) line 160 I get the following values (when I try to create /User:John/Testpage):
```
'code':
404
'trace':
#0 /var/www/html/w/extensions/VisualEditor/includes/ApiVisualEditor.php(67): ApiVisualEditor->requestRestbase(Object(Title), 'POST', 'transform/wikit...', Array)
#1 /var/www/html/w/extensions/VisualEditor/includes/ApiVisualEditor.php(251): ApiVisualEditor->parseWikitextFragment(Object(Title), 'testtext', false, NULL, true)
#2 /var/www/html/w/includes/api/ApiMain.php(1593): ApiVisualEditor->execute()
#3 /var/www/html/w/includes/api/ApiMain.php(529): ApiMain->executeAction()
#4 /var/www/html/w/includes/api/ApiMain.php(500): ApiMain->executeActionWithErrorHandling()
#5 /var/www/html/w/api.php(90): ApiMain->execute()
#6 /var/www/html/w/api.php(45): wfApiMain()
#7 {main}
'response':
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"> <html><head> <title>404 Not Found</title> </head><body> <h1>Not Found</h1> <p>The requested URL was not found on this server.</p> <hr> <address>Apache/2.4.38 (Debian) Server at localhost Port 80</address> </body></html>
'requestPath':
transform/wikitext/to/html/User%3AJohn%2FTestpage
```
What looks strange to me is this part:
```
'requestPath': transform/wikitext/to/html/User%3AJohn%2FTestpage
```
given that some / are sanitized and some are not. So what I did is remove the function urlencode from lines 230 & 250 in file ApiParsoidTrait.php then Visual Editor creates new pages either inside the User namespace or subpages in the Main namespace without problem.
i.e. the use of urlencode there seems to create problems.