ddev: install autocompletion scripts (#384953)

pkgs/by-name/dd/ddev/package.nix

@@ -1,4 +1,12 @@
-{ lib, buildGoModule, fetchFromGitHub, testers, ddev }:
+{
+  lib,
+  stdenv,
+  buildGoModule,
+  fetchFromGitHub,
+  installShellFiles,
+  testers,
+  ddev,
+}:
 
 buildGoModule rec {
   pname = "ddev";
@@ -11,6 +19,10 @@ buildGoModule rec {
     hash = "sha256-q1bLnwVNFAtnG5tCn7ox4lgaXM60rrVEcWgBNuRJcSU=";
   };
 
+  nativeBuildInputs = [
+    installShellFiles
+  ];
+
   vendorHash = null;
 
   ldflags = [
@@ -22,6 +34,17 @@ buildGoModule rec {
   # Tests need docker.
   doCheck = false;
 
+  postInstall = lib.optionalString (stdenv.buildPlatform.canExecute stdenv.hostPlatform) ''
+    # DDEV will try to create $HOME/.ddev, so we set $HOME to a temporary
+    # directory.
+    export HOME=$(mktemp -d)
+    $out/bin/ddev_gen_autocomplete
+    installShellCompletion --cmd ddev \
+      --bash .gotmp/bin/completions/ddev_bash_completion.sh \
+      --fish .gotmp/bin/completions/ddev_fish_completion.sh \
+      --zsh .gotmp/bin/completions/ddev_zsh_completion.sh
+  '';
+
   passthru.tests.version = testers.testVersion {
     package = ddev;
     command = ''