AllowOverride and RewriteCond/RewriteRule interactions - apache

Question

I'm trying to set up a site running on Apache 2.4.16 to redirect all www URLs to non-www URLs. I'm using HTML5 Boilerplate's Apache configs to do this (as well as everything else they provide).
https://github.com/h5bp/server-configs-apache/blob/master/dist/.htaccess
This happens on line 380, seen below:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTPS} !=on
RewriteCond %{HTTP_HOST} ^www\.(.+)$ [NC]
RewriteRule ^ %{ENV:PROTO}://%1%{REQUEST_URI} [R=301,L]
</IfModule>
I'm using Include to add the whole file to my vhost config for the site, as well as an AllowOverride All for another .htaccess file at my doc root (same one that comes with Laravel 5):
production.vhost.conf (relevant part)
<Directory /var/www/hostname/production>
AllowOverride All
# Include H5BP server configs
Include server-configs-apache/dist/.htaccess
</Directory>
.htaccess (at doc root)
<IfModule mod_rewrite.c>
<IfModule mod_negotiation.c>
Options -MultiViews
</IfModule>
RewriteEngine On
# Redirect Trailing Slashes If Not A Folder...
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)/$ /$1 [L,R=301]
# Handle Front Controller...
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ index.php [L]
</IfModule>
Now, almost everything from H5BP's .htaccess was working, except for the redirect from www to non-www. After poking around I noticed that the redirect was only working when I'd remove AllowOverride All from the <Directory> block in the vhost. So the doc root .htaccess was somehow overriding the rewrite conditions.
I've actually already fixed my initial issue by moving the doc root .htaccess contents into the vhost file and removing the AllowOverride, but I'm more curious as to why this was happening; more specifically how AllowOverride interacts with RewriteCond and RewriteRule.
My hunch is that the .htaccess in my doc root was overriding the www to non-www redirect, but I'm not sure why that one specifically. For example, the http -> https redirect worked without issue (line 352 of H5BP, uncommented out in mine), it seemed to be just that one redirect. I didnt even think that those rules could be overridden since RewriteCond/RewriteRules feel unique to me.
If there are any, what are the rules that determine how an .htaccess can override a rewrite rule?

Answer 1

If there are any, what are the rules that determine how an .htaccess
can override a rewrite rule?
Conditions and rules don't dictate how .htaccess works. AllowOverride is what allows .htaccess usage. If you have AllowOverride All then .htaccess is allowed, if you have AllowOverride None, then it's not and it will be ignored. In 2.4 None is the default.
.htaccess is per directory so it will take precedence if it's located in a directory that has rules applied as long as .htaccess file usage is allowed there. Which is confgiured in the server config in VirtualHost or Directory directives.
Also using an include for .htaccess in a vhost is a very bad configuration. If you have access to the vhost file or the config, you should create another config and include it with the .htaccess contents.
You should not be using .htaccess files at all actually with access to the server config. See this apache recommendation on not using .htaccess.
https://httpd.apache.org/docs/2.4/howto/htaccess.html#when