FPM: Always use script name in PHP_SELF if cgi.discard_path = 1 and cgi.fix_pathinfo = 0

[bukka]

Description

Currently if PATH_INFO set, then it is used in PHP_SELF if cgi.fix_pathinfo is disabled. This makes sense if the executable is used from PATH_TRANSLATED which is default behaviour. However if cgi.discard_path is enabled, it uses SCRIPT_FILENAME executable instead. This however does not match the documentation which states that PHP_SELF is relative path to the executable because PATH_INFO has nothing to do with executable path.

This was first mentioned in https://bugs.php.net/bug.php?id=68053 and this issue is an extraction of that problem (the primary concern won't be fixed due to a significant BC break). Even though this could be considered as a bug, it is not that critical and it has some BC break concern. It means it should be treated more as a feature change to improve the current behaviour and should go only to master and be mentioned in UPGRADING.

[bukka]

Just comment for myself. The fix should be pretty much just

diff --git a/sapi/fpm/fpm/fpm_main.c b/sapi/fpm/fpm/fpm_main.c
index 64ef27dade..61c24b7569 100644
--- a/sapi/fpm/fpm/fpm_main.c
+++ b/sapi/fpm/fpm/fpm_main.c
@@ -1310,7 +1310,7 @@ static void init_request_info(void)
                        }
                } else {
                        /* pre 4.3 behaviour, shouldn't be used but provides BC */
-                       if (env_path_info) {
+                       if (!CGIG(discard_path) && env_path_info) {
                                SG(request_info).request_uri = env_path_info;
                        } else {
                                SG(request_info).request_uri = env_script_name;

and some changes in the tests. I'm still working on better coverage so will address it once all the tests are added.

[danog]

@bukka I feel this is a more general issue, as PHP_SELF shouldn't contain the PATH_INFO in any case, regardless of the value of fix_pathinfo, but it is specifically appended if fix_pathinfo is true: https://github.com/php/php-src/blob/master/sapi/fpm/fpm/fpm_main.c#L560