Merge pull request #208867 from K900/qt-doc-fixes

treewide: remove outdated multiple versions of Qt stuff

1 files changed, 4 insertions, 70 deletions

diff --git a/doc/languages-frameworks/qt.section.md b/doc/languages-frameworks/qt.section.md
index 986deeb0d4b22..e09194e391e1c 100644
--- a/doc/languages-frameworks/qt.section.md
+++ b/doc/languages-frameworks/qt.section.md
@@ -2,14 +2,11 @@
 
 Writing Nix expressions for Qt libraries and applications is largely similar as for other C++ software.
 This section assumes some knowledge of the latter.
-There are two problems that the Nixpkgs Qt infrastructure addresses,
-which are not shared by other C++ software:
 
-1.  There are usually multiple supported versions of Qt in Nixpkgs.
-    All of a package's dependencies must be built with the same version of Qt.
-    This is similar to the version constraints imposed on interpreted languages like Python.
-2.  Qt makes extensive use of runtime dependency detection.
-    Runtime dependencies are made into build dependencies through wrappers.
+The major caveat with Qt applications is that Qt uses a plugin system to load additional modules at runtime,
+from a list of well-known locations. In Nixpkgs, we patch QtCore to instead use an environment variable,
+and wrap Qt applications to set it to the right paths. This effectively makes the runtime dependencies
+pure and explicit at build-time, at the cost of introducing an extra indirection.
 
 ## Nix expression for a Qt package (default.nix) {#qt-default-nix}
 
@@ -95,66 +92,3 @@ stdenv.mkDerivation {
 This means that scripts won't be automatically wrapped so you'll need to manually wrap them as previously mentioned.
 An example of when you'd always need to do this is with Python applications that use PyQt.
 :::
-
-## Adding a library to Nixpkgs {#adding-a-library-to-nixpkgs}
-
-Add Qt libraries to `qt5-packages.nix` to make them available for every
-supported Qt version.
-
-### Example adding a Qt library {#qt-library-all-packages-nix}
-
-The following represents the contents of `qt5-packages.nix`.
-
-```nix
-{
-  # ...
-
-  mylib = callPackage ../path/to/mylib {};
-
-  # ...
-}
-```
-
-Libraries are built with every available version of Qt.
-Use the `meta.broken` attribute to disable the package for unsupported Qt versions:
-
-```nix
-{ stdenv, lib, qtbase }:
-
-stdenv.mkDerivation {
-  # ...
-  # Disable this library with Qt < 5.9.0
-  meta.broken = lib.versionOlder qtbase.version "5.9.0";
-}
-```
-
-## Adding an application to Nixpkgs {#adding-an-application-to-nixpkgs}
-
-Add Qt applications to `qt5-packages.nix`. Add an alias to `all-packages.nix`
-to select the Qt 5 version used for the application.
-
-### Example adding a Qt application {#qt-application-all-packages-nix}
-
-The following represents the contents of `qt5-packages.nix`.
-
-```nix
-{
-  # ...
-
-  myapp = callPackage ../path/to/myapp {};
-
-  # ...
-}
-```
-
-The following represents the contents of `all-packages.nix`.
-
-```nix
-{
-  # ...
-
-  myapp = libsForQt5.myapp;
-
-  # ...
-}
-```