1 files changed, 64 insertions, 39 deletions
diff --git a/nixpkgs/doc/languages-frameworks/php.section.md b/nixpkgs/doc/languages-frameworks/php.section.md
index a302a9a7f87d..763beeb59358 100644
--- a/nixpkgs/doc/languages-frameworks/php.section.md
+++ b/nixpkgs/doc/languages-frameworks/php.section.md
@@ -1,26 +1,30 @@
-# PHP
+# PHP {#sec-php}
 
-## User Guide
+## User Guide {#ssec-php-user-guide}
 
-### Using PHP
-
-#### Overview
+### Overview {#ssec-php-user-guide-overview}
 
 Several versions of PHP are available on Nix, each of which having a
 wide variety of extensions and libraries available.
 
-The attribute `php` refers to the version of PHP considered most
-stable and thoroughly tested in nixpkgs for any given release of
-NixOS. Note that while this version of PHP may not be the latest major
-release from upstream, any version of PHP supported in nixpkgs may be
-utilized by specifying the desired attribute by version, such as
-`php74`.
+The different versions of PHP that nixpkgs provides are located under
+attributes named based on major and minor version number; e.g.,
+`php74` is PHP 7.4.
 
 Only versions of PHP that are supported by upstream for the entirety
 of a given NixOS release will be included in that release of
 NixOS. See [PHP Supported
 Versions](https://www.php.net/supported-versions.php).
 
+The attribute `php` refers to the version of PHP considered most
+stable and thoroughly tested in nixpkgs for any given release of
+NixOS - not necessarily the latest major release from upstream.
+
+All available PHP attributes are wrappers around their respective
+binary PHP package and provide commonly used extensions this way. The
+real PHP 7.4 package, i.e. the unwrapped one, is available as
+`php74.unwrapped`; see the next section for more details.
+
 Interactive tools built on PHP are put in `php.packages`; composer is
 for example available at `php.packages.composer`.
 
@@ -30,39 +34,44 @@ opcache extension shipped with PHP is available at
 `php.extensions.opcache` and the third-party ImageMagick extension at
 `php.extensions.imagick`.
 
-The different versions of PHP that nixpkgs provides is located under
-attributes named based on major and minor version number; e.g.,
-`php74` is PHP 7.4 with commonly used extensions installed,
-`php74base` is the same PHP runtime without extensions.
-
-#### Installing PHP with packages
+### Installing PHP with extensions {#ssec-php-user-guide-installing-with-extensions}
 
 A PHP package with specific extensions enabled can be built using
 `php.withExtensions`. This is a function which accepts an anonymous
-function as its only argument; the function should take one argument,
-the set of all extensions, and return a list of wanted extensions. For
-example, a PHP package with the opcache and ImageMagick extensions
-enabled:
+function as its only argument; the function should accept two named
+parameters: `enabled` - a list of currently enabled extensions and
+`all` - the set of all extensions, and return a list of wanted
+extensions. For example, a PHP package with all default extensions and
+ImageMagick enabled:
 
 ```nix
-php.withExtensions (e: with e; [ imagick opcache ])
+php.withExtensions ({ enabled, all }:
+  enabled ++ [ all.imagick ])
 ```
 
-Note that this will give you a package with _only_ opcache and
-ImageMagick, none of the other extensions which are enabled by default
-in the `php` package will be available.
+To exclude some, but not all, of the default extensions, you can
+filter the `enabled` list like this:
 
-To enable building on a previous PHP package, the currently enabled
-extensions are made available in its `enabledExtensions`
-attribute. For example, to generate a package with all default
-extensions enabled, except opcache, but with ImageMagick:
+```nix
+php.withExtensions ({ enabled, all }:
+  (lib.filter (e: e != php.extensions.opcache) enabled)
+  ++ [ all.imagick ])
+```
+
+To build your list of extensions from the ground up, you can simply
+ignore `enabled`:
 
 ```nix
-php.withExtensions (e:
-  (lib.filter (e: e != php.extensions.opcache) php.enabledExtensions)
-  ++ [ e.imagick ])
+php.withExtensions ({ all, ... }: with all; [ imagick opcache ])
 ```
 
+`php.withExtensions` provides extensions by wrapping a minimal php
+base package, providing a `php.ini` file listing all extensions to be
+loaded. You can access this package through the `php.unwrapped`
+attribute; useful if you, for example, need access to the `dev`
+output. The generated `php.ini` file can be accessed through the
+`php.phpIni` attribute.
+
 If you want a PHP build with extra configuration in the `php.ini`
 file, you can use `php.buildEnv`. This function takes two named and
 optional parameters: `extensions` and `extraConfig`. `extensions`
@@ -73,19 +82,19 @@ and ImageMagick extensions enabled, and `memory_limit` set to `256M`:
 
 ```nix
 php.buildEnv {
-  extensions = e: with e; [ imagick opcache ];
+  extensions = { all, ... }: with all; [ imagick opcache ];
   extraConfig = "memory_limit=256M";
 }
 ```
 
-##### Example setup for `phpfpm`
+#### Example setup for `phpfpm` {#ssec-php-user-guide-installing-with-extensions-phpfpm}
 
 You can use the previous examples in a `phpfpm` pool called `foo` as
 follows:
 
 ```nix
 let
-  myPhp = php.withExtensions (e: with e; [ imagick opcache ]);
+  myPhp = php.withExtensions ({ all, ... }: with all; [ imagick opcache ]);
 in {
   services.phpfpm.pools."foo".phpPackage = myPhp;
 };
@@ -94,7 +103,7 @@ in {
 ```nix
 let
   myPhp = php.buildEnv {
-    extensions = e: with e; [ imagick opcache ];
+    extensions = { all, ... }: with all; [ imagick opcache ];
     extraConfig = "memory_limit=256M";
   };
 in {
@@ -102,11 +111,27 @@ in {
 };
 ```
 
-##### Example usage with `nix-shell`
+#### Example usage with `nix-shell` {#ssec-php-user-guide-installing-with-extensions-nix-shell}
 
 This brings up a temporary environment that contains a PHP interpreter
-with the extensions `imagick` and `opcache` enabled.
+with the extensions `imagick` and `opcache` enabled:
 
 ```sh
-nix-shell -p 'php.buildEnv { extensions = e: with e; [ imagick opcache ]; }'
+nix-shell -p 'php.withExtensions ({ all, ... }: with all; [ imagick opcache ])'
+```
+
+### Installing PHP packages with extensions {#ssec-php-user-guide-installing-packages-with-extensions}
+
+All interactive tools use the PHP package you get them from, so all
+packages at `php.packages.*` use the `php` package with its default
+extensions. Sometimes this default set of extensions isn't enough and
+you may want to extend it. A common case of this is the `composer`
+package: a project may depend on certain extensions and `composer`
+won't work with that project unless those extensions are loaded.
+
+Example of building `composer` with additional extensions:
+```nix
+(php.withExtensions ({ all, enabled }:
+  enabled ++ (with all; [ imagick redis ]))
+).packages.composer
 ```