Merge pull request codeigniter4#7287 from kenjis/docs-add-file-case-sensitive

docs: add note for case-sensitive file systems

Author: samsonasik

user_guide_src/source/concepts/autoloader.rst

@@ -13,6 +13,9 @@ classes that your project is using. Keeping track of where every single file is,
 hard-coding that location into your files in a series of ``requires()`` is a massive
 headache and very error-prone. That's where autoloaders come in.
 
+CodeIgniter4 Autoloader
+***********************
+
 CodeIgniter provides a very flexible autoloader that can be used with very little configuration.
 It can locate individual namespaced classes that adhere to
 `PSR-4 <https://www.php-fig.org/psr/psr-4/>`_ autoloading
@@ -27,6 +30,12 @@ they work in sequence and don't get in each other's way.
 The autoloader is always active, being registered with ``spl_autoload_register()`` at the
 beginning of the framework's execution.
 
+.. important:: You should always be careful about the case of filenames. Many
+    developers develop on case-insensitive file systems on Windows or macOS.
+    However, most server environments use case-sensitive file systems. If the
+    file name case is incorrect, the autoloader cannot find the file on the
+    server.
+
 Configuration
 *************
 

user_guide_src/source/installation/running.rst

@@ -9,6 +9,12 @@ A CodeIgniter 4 app can be run in a number of different ways: hosted on a web se
 using virtualization, or using CodeIgniter's command line tool for testing.
 This section addresses how to use each technique, and explains some of the pros and cons of them.
 
+.. important:: You should always be careful about the case of filenames. Many
+    developers develop on case-insensitive file systems on Windows or macOS.
+    However, most server environments use case-sensitive file systems. If the
+    file name case is incorrect, code that works locally will not work on the
+    server.
+
 If you're new to CodeIgniter, please read the :doc:`Getting Started </intro/index>`
 section of the User Guide to begin learning how to build dynamic PHP applications. Enjoy!
 

user_guide_src/source/installation/troubleshooting.rst

@@ -56,6 +56,19 @@ If you see "No input file specified", try to change the rewrite rule like the fo
 
     RewriteRule ^([\s\S]*)$ index.php?/$1 [L,NC,QSA]
 
+My app works fine locally but not on the production server
+----------------------------------------------------------
+
+Make sure that the case of the folder and file names matches the code.
+
+Many developers develop on case-insensitive file systems on Windows or macOS.
+However, most server environments use case-sensitive file systems.
+
+For example, when you have **app/Controllers/Product.php**, you must use
+``Product`` as the short classname, not ``product``.
+
+If the file name case is incorrect, the file is not found on the server.
+
 The tutorial gives 404 errors everywhere :(
 -------------------------------------------
 

user_guide_src/source/tutorial/static_pages.rst

@@ -19,6 +19,12 @@ Let's Make our First Controller
 Create a file at **app/Controllers/Pages.php** with the following
 code.
 
+.. important:: You should always be careful about the case of filenames. Many
+    developers develop on case-insensitive file systems on Windows or macOS.
+    However, most server environments use case-sensitive file systems. If the
+    file name case is incorrect, code that works locally will not work on the
+    server.
+
 .. literalinclude:: static_pages/001.php
 
 You have created a class named ``Pages``, with a ``view()`` method that accepts