Ok merci à toi j'ai géré le truc avec un header () php qui redirige. C'est pas ce que je voulais faire à la base mais ça convient au chef.

Salut, déjà le répertoire racine du nom de domaine ou de l'alias doit être le dossier web du projet Symfony. Ça c'est de la configuration du serveur web, apache je suppose.
Et ensuite le htaccess doit faire le job pour ne pas avoir besoin de spécifier le fichier app.php.

Bonjour Pour une application métier en symfony 2.8 avec mon collègue nous cherchons à faire en sorte que l’url de base soit : http://xampdev/prevision_paiement/ et non http://xampdev/prevision_paiement/web/app.php/
La première adresse nous renvoie à l’index de l’application avec toute l’architecture des fichiers….

Nous sommes tombés sur ces topics en faisant nos recherches :
https://openclassrooms.com/forum/sujet/symfony-2-url-rewriting-vers-web-avec-htaccess-96060
…qui renvoie sur la dernière partie du cours suivant :
https://openclassrooms.com/fr/courses/3619856-developpez-votre-site-web-avec-le-framework-symfony/3626249-deployer-son-site-symfony-en-production

Qui nous disent de modifier le fichier .htaccess dans le fichier web.

[code]
# Use the front controller as index file. It serves as a fallback solution when
# every other rewrite/redirect fails (e.g. in an aliased environment without
# mod_rewrite). Additionally, this reduces the matching process for the
# start page (path "/") because otherwise Apache will apply the rewriting rules
# to each configured DirectoryIndex file (e.g. index.php, index.html, index.pl).
DirectoryIndex app.php

# By default, Apache does not evaluate symbolic links if you did not enable this
# feature in your server configuration. Uncomment the following line if you
# install assets as symlinks or if you experience problems related to symlinks
# when compiling LESS/Sass/CoffeScript assets.
# Options FollowSymlinks

# Disabling MultiViews prevents unwanted negotiation, e.g. "/app" should not resolve
# to the front controller "/app.php" but be rewritten to "/app.php/app".
<IfModule mod_negotiation.c>
Options -MultiViews
</IfModule>

<IfModule mod_rewrite.c>
RewriteEngine On

# Determine the RewriteBase automatically and set it as environment variable.
# If you are using Apache aliases to do mass virtual hosting or installed the
# project in a subdirectory, the base path will be prepended to allow proper
# resolution of the app.php file and to redirect to the correct URI. It will
# work in environments without path prefix as well, providing a safe, one-size
# fits all solution. But as you do not need it in this case, you can comment
# the following 2 lines to eliminate the overhead.
RewriteCond %{REQUEST_URI}::$1 ^(/.+)/(.*)::\2$
RewriteRule ^(.*) - [E=BASE:%1]

# Sets the HTTP_AUTHORIZATION header removed by apache
RewriteCond %{HTTP:Authorization} .
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]

# Redirect to URI without front controller to prevent duplicate content
# (with and without `/app.php`). Only do this redirect on the initial
# rewrite by Apache and not on subsequent cycles. Otherwise we would get an
# endless redirect loop (request -> rewrite to front controller ->
# redirect -> request -> ...).
# So in case you get a "too many redirects" error or you always get redirected
# to the start page because your Apache does not expose the REDIRECT_STATUS
# environment variable, you have 2 choices:
# - disable this feature by commenting the following 2 lines or
# - use Apache >= 2.3.9 and replace all L flags by END flags and remove the
# following RewriteCond (best solution)
RewriteCond %{ENV:REDIRECT_STATUS} ^$
RewriteRule ^app\.php(/(.*)|$) %{ENV:BASE}/$2 [R=301,L]

# If the requested filename exists, simply serve it.
# We only want to let Apache serve files and not directories.
# RewriteCond %{REQUEST_FILENAME} -f
# RewriteRule .? - [L]

# Rewrite all other queries to the front controller.
# RewriteRule .? %{ENV:BASE}/app.php [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ web/$1 [QSA,L]
</IfModule>

<IfModule !mod_rewrite.c>
<IfModule mod_alias.c>
# When mod_rewrite is not available, we instruct a temporary redirect of
# the start page to the front controller explicitly so that the website
# and the generated links can still be used.
RedirectMatch 302 ^/$ /app.php/
# RedirectTemp cannot be used instead
</IfModule>
</IfModule>
[/code]

ça ramène toujours à l’index pourtant on a bien changé les lignes qui étaient à changer à savoir :
mise en commentaire des lignes 53, 54 et 57
# RewriteCond %{REQUEST_FILENAME} -f
# RewriteRule .? - [L]
# RewriteRule .? %{ENV:BASE}/app.php [L]
Et ajout des lignes 58 et 59 :
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ web/$1 [QSA,L]

Bref on comprend pas pourquoi ça ne nous supprime pas les deux dernières étapes du chemin /web/app.php/
On ne comprend pas pourquoi ceux qui avaient le problème ont bien réussi à le résoudre….