mkShell: introduce packages argument (#122180)

The distinction between the inputs doesn't really make sense in the
mkShell context.  Technically speaking, we should be using the
nativeBuildInputs most of the time.

So in order to make this function more beginner-friendly, add "packages"
as an attribute, that maps to nativeBuildInputs.

This commit also updates all the uses in nixpkgs.

13 files changed, 40 insertions, 31 deletions

diff --git a/doc/builders/special/mkshell.section.md b/doc/builders/special/mkshell.section.md
index 1feb75cbd6f..8a62c50e17d 100644
--- a/doc/builders/special/mkshell.section.md
+++ b/doc/builders/special/mkshell.section.md
@@ -1,15 +1,17 @@
 # pkgs.mkShell {#sec-pkgs-mkShell}
 
-`pkgs.mkShell` is a special kind of derivation that is only useful when using it combined with `nix-shell`. It will in fact fail to instantiate when invoked with `nix-build`.
+`pkgs.mkShell` is a special kind of derivation that is only useful when using
+it combined with `nix-shell`. It will in fact fail to instantiate when invoked
+with `nix-build`.
 
 ## Usage {#sec-pkgs-mkShell-usage}
 
 ```nix
 { pkgs ? import <nixpkgs> {} }:
 pkgs.mkShell {
-  # this will make all the build inputs from hello and gnutar
-  # available to the shell environment
+  # specify which packages to add to the shell environment
+  packages = [ pkgs.gnumake ];
+  # add all the dependencies, of the given packages, to the shell environment
   inputsFrom = with pkgs; [ hello gnutar ];
-  buildInputs = [ pkgs.gnumake ];
 }
 ```
diff --git a/doc/languages-frameworks/dotnet.section.md b/doc/languages-frameworks/dotnet.section.md
index 36369fd4e63..725ffd4becc 100644
--- a/doc/languages-frameworks/dotnet.section.md
+++ b/doc/languages-frameworks/dotnet.section.md
@@ -10,7 +10,7 @@ with import <nixpkgs> {};
 
 mkShell {
   name = "dotnet-env";
-  buildInputs = [
+  packages = [
     dotnet-sdk_3
   ];
 }
@@ -25,7 +25,7 @@ with import <nixpkgs> {};
 
 mkShell {
   name = "dotnet-env";
-  buildInputs = [
+  packages = [
     (with dotnetCorePackages; combinePackages [
       sdk_3_1
       sdk_3_0
diff --git a/doc/languages-frameworks/python.section.md b/doc/languages-frameworks/python.section.md
index 96ac61ab54c..b466748f548 100644
--- a/doc/languages-frameworks/python.section.md
+++ b/doc/languages-frameworks/python.section.md
@@ -245,7 +245,7 @@ let
     ps.toolz
   ]);
 in mkShell {
-  buildInputs = [
+  packages = [
     pythonEnv
 
     black
diff --git a/doc/languages-frameworks/ruby.section.md b/doc/languages-frameworks/ruby.section.md
index c519d79d3da..b8fc19eb6b0 100644
--- a/doc/languages-frameworks/ruby.section.md
+++ b/doc/languages-frameworks/ruby.section.md
@@ -106,7 +106,7 @@ let
     name = "gems-for-some-project";
     gemdir = ./.;
   };
-in mkShell { buildInputs = [ gems gems.wrappedRuby ]; }
+in mkShell { packages = [ gems gems.wrappedRuby ]; }
 ```
 
 With this file in your directory, you can run `nix-shell` to build and use the gems. The important parts here are `bundlerEnv` and `wrappedRuby`.
diff --git a/maintainers/scripts/update-luarocks-shell.nix b/maintainers/scripts/update-luarocks-shell.nix
index 23a940b3691..d3f342b07a9 100644
--- a/maintainers/scripts/update-luarocks-shell.nix
+++ b/maintainers/scripts/update-luarocks-shell.nix
@@ -2,8 +2,11 @@
 }:
 with nixpkgs;
 mkShell {
-  buildInputs = [
-    bash luarocks-nix nix-prefetch-scripts parallel
+  packages = [
+    bash
+    luarocks-nix
+    nix-prefetch-scripts
+    parallel
   ];
   LUAROCKS_NIXPKGS_PATH = toString nixpkgs.path;
 }
diff --git a/nixos/doc/manual/shell.nix b/nixos/doc/manual/shell.nix
index cc3609d750e..e5ec9b8f97f 100644
--- a/nixos/doc/manual/shell.nix
+++ b/nixos/doc/manual/shell.nix
@@ -4,5 +4,5 @@ in
 pkgs.mkShell {
   name = "nixos-manual";
 
-  buildInputs = with pkgs; [ xmlformat jing xmloscopy ruby ];
+  packages = with pkgs; [ xmlformat jing xmloscopy ruby ];
 }
diff --git a/pkgs/applications/editors/emacs-modes/emacs2nix.nix b/pkgs/applications/editors/emacs-modes/emacs2nix.nix
index cc82646870c..658756250a0 100644
--- a/pkgs/applications/editors/emacs-modes/emacs2nix.nix
+++ b/pkgs/applications/editors/emacs-modes/emacs2nix.nix
@@ -7,10 +7,10 @@ let
     rev = "860da04ca91cbb69c9b881a54248d16bdaaf9923";
     sha256 = "1r3xmyk9rfgx7ln69dk8mgbnh3awcalm3r1c5ia2shlsrymvv1df";
   };
+in
+pkgs.mkShell {
 
-in pkgs.mkShell {
-
-  buildInputs = [
+  packages = [
     pkgs.bash
   ];
 
diff --git a/pkgs/applications/editors/emacs-modes/updater-emacs.nix b/pkgs/applications/editors/emacs-modes/updater-emacs.nix
index 4c321065445..7502bcc2fee 100644
--- a/pkgs/applications/editors/emacs-modes/updater-emacs.nix
+++ b/pkgs/applications/editors/emacs-modes/updater-emacs.nix
@@ -29,7 +29,7 @@ let
   in [ promise semaphore ]);
 
 in pkgs.mkShell {
-  buildInputs = [
+  packages = [
     pkgs.git
     pkgs.nix
     pkgs.bash
diff --git a/pkgs/applications/networking/cluster/nixops/shell.nix b/pkgs/applications/networking/cluster/nixops/shell.nix
index 3fc06b0bc73..0139cb2c812 100644
--- a/pkgs/applications/networking/cluster/nixops/shell.nix
+++ b/pkgs/applications/networking/cluster/nixops/shell.nix
@@ -1,7 +1,7 @@
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? import <nixpkgs> { } }:
 
 pkgs.mkShell {
-  buildInputs = [
+  packages = [
     pkgs.poetry2nix.cli
     pkgs.pkg-config
     pkgs.libvirt
diff --git a/pkgs/build-support/agda/default.nix b/pkgs/build-support/agda/default.nix
index 984d61f1f75..ed7d11a1314 100644
--- a/pkgs/build-support/agda/default.nix
+++ b/pkgs/build-support/agda/default.nix
@@ -1,6 +1,6 @@
 # Builder for Agda packages.
 
-{ stdenv, lib, self, Agda, runCommandNoCC, makeWrapper, writeText, mkShell, ghcWithPackages, nixosTests }:
+{ stdenv, lib, self, Agda, runCommandNoCC, makeWrapper, writeText, ghcWithPackages, nixosTests }:
 
 with lib.strings;
 
diff --git a/pkgs/build-support/mkshell/default.nix b/pkgs/build-support/mkshell/default.nix
index a70dc0390cb..7ca4cc23c1d 100644
--- a/pkgs/build-support/mkshell/default.nix
+++ b/pkgs/build-support/mkshell/default.nix
@@ -3,18 +3,22 @@
 # A special kind of derivation that is only meant to be consumed by the
 # nix-shell.
 {
-  inputsFrom ? [], # a list of derivations whose inputs will be made available to the environment
-  buildInputs ? [],
-  nativeBuildInputs ? [],
-  propagatedBuildInputs ? [],
-  propagatedNativeBuildInputs ? [],
-  ...
+  # a list of packages to add to the shell environment
+  packages ? [ ]
+, # propagate all the inputs from the given derivations
+  inputsFrom ? [ ]
+, buildInputs ? [ ]
+, nativeBuildInputs ? [ ]
+, propagatedBuildInputs ? [ ]
+, propagatedNativeBuildInputs ? [ ]
+, ...
 }@attrs:
 let
   mergeInputs = name: lib.concatLists (lib.catAttrs name
-    ([attrs] ++ inputsFrom));
+    ([ attrs ] ++ inputsFrom));
 
   rest = builtins.removeAttrs attrs [
+    "packages"
     "inputsFrom"
     "buildInputs"
     "nativeBuildInputs"
@@ -26,15 +30,15 @@ in
 
 stdenv.mkDerivation ({
   name = "nix-shell";
-  phases = ["nobuildPhase"];
+  phases = [ "nobuildPhase" ];
 
   buildInputs = mergeInputs "buildInputs";
-  nativeBuildInputs = mergeInputs "nativeBuildInputs";
+  nativeBuildInputs = packages ++ (mergeInputs "nativeBuildInputs");
   propagatedBuildInputs = mergeInputs "propagatedBuildInputs";
   propagatedNativeBuildInputs = mergeInputs "propagatedNativeBuildInputs";
 
   shellHook = lib.concatStringsSep "\n" (lib.catAttrs "shellHook"
-    (lib.reverseList inputsFrom ++ [attrs]));
+    (lib.reverseList inputsFrom ++ [ attrs ]));
 
   nobuildPhase = ''
     echo
diff --git a/pkgs/development/mobile/androidenv/examples/shell.nix b/pkgs/development/mobile/androidenv/examples/shell.nix
index 95f6a3bdbba..45cccf22c7d 100644
--- a/pkgs/development/mobile/androidenv/examples/shell.nix
+++ b/pkgs/development/mobile/androidenv/examples/shell.nix
@@ -115,7 +115,7 @@ let
 in
 pkgs.mkShell rec {
   name = "androidenv-demo";
-  buildInputs = [ androidSdk platformTools jdk pkgs.android-studio ];
+  packages = [ androidSdk platformTools jdk pkgs.android-studio ];
 
   LANG = "C.UTF-8";
   LC_ALL = "C.UTF-8";
diff --git a/pkgs/tools/X11/opentabletdriver/shell.nix b/pkgs/tools/X11/opentabletdriver/shell.nix
index 526fa4a4432..4367d22e9df 100644
--- a/pkgs/tools/X11/opentabletdriver/shell.nix
+++ b/pkgs/tools/X11/opentabletdriver/shell.nix
@@ -1,9 +1,9 @@
-{ pkgs ? import ../../../../. {} }:
+{ pkgs ? import ../../../../. { } }:
 
 with pkgs;
 
 mkShell {
-  buildInputs = [
+  packages = [
     common-updater-scripts
     curl
     dotnetCorePackages.sdk_5_0