From efc104c4c8dd8eb0f2eb2de13d36a2d0c47012df Mon Sep 17 00:00:00 2001
From: Peter Simons <simons@cryp.to>
Date: Tue, 16 Oct 2012 18:23:28 +0200
Subject: [PATCH] modules/programs/bash: improve bash completion support

The new configuration.nix option 'environment.enableBashCompletion'
determines whether bash completion is automatically enabled system-wide
for all interactive shells or not. The default setting is 'off'.
---
 modules/programs/bash/bash.nix  | 31 ++++++++++++++++++++++++++++++-
 modules/programs/bash/bashrc.sh | 10 +---------
 2 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/modules/programs/bash/bash.nix b/modules/programs/bash/bash.nix
index 51654b164a0..9eefb8e686f 100644
--- a/modules/programs/bash/bash.nix
+++ b/modules/programs/bash/bash.nix
@@ -7,6 +7,25 @@ with pkgs.lib;
 
 let
 
+  initBashCompletion = optionalString config.environment.enableBashCompletion ''
+    # Check whether we're running a version of Bash that has support for
+    # programmable completion. If we do, enable all modules installed in
+    # the system (and user profile).
+    if shopt -q progcomp &>/dev/null; then
+      . "${pkgs.bashCompletion}/etc/profile.d/bash_completion.sh"
+      nullglobStatus=$(shopt -p nullglob)
+      shopt -s nullglob
+      for p in $NIX_PROFILES /run/current-system/sw; do
+        for m in "$p/etc/bash_completion.d/"*; do
+          echo enable bash completion module $m
+          . $m
+        done
+      done
+      eval "$nullglobStatus"
+    fi
+  '';
+
+
   options = {
 
     environment.shellInit = mkOption {
@@ -18,6 +37,12 @@ let
         type = with pkgs.lib.types; string;
       };
 
+    environment.enableBashCompletion = mkOption {
+        default = false;
+        description = "Enable bash-completion for all interactive shells.";
+        type = with pkgs.lib.types; bool;
+      };
+
   };
 
 in
@@ -38,7 +63,10 @@ in
       { # /etc/bashrc: executed every time a bash starts. Sources
         # /etc/profile to ensure that the system environment is
         # configured properly.
-         source = ./bashrc.sh;
+         source = pkgs.substituteAll {
+           src = ./bashrc.sh;
+           inherit initBashCompletion;
+         };
          target = "bashrc";
       }
 
@@ -59,4 +87,5 @@ in
       mv /bin/.sh.tmp /bin/sh # atomically replace /bin/sh
     '';
 
+  environment.pathsToLink = optional config.environment.enableBashCompletion "/etc/bash_completion.d";
 }
diff --git a/modules/programs/bash/bashrc.sh b/modules/programs/bash/bashrc.sh
index 74550656151..4382e7ee9d8 100644
--- a/modules/programs/bash/bashrc.sh
+++ b/modules/programs/bash/bashrc.sh
@@ -27,15 +27,7 @@ if test "$TERM" = "xterm"; then
     PS1="\[\033]2;\h:\u:\w\007\]$PS1"
 fi
 
-# Check whether we're running a version of Bash that has support for
-# programmable completion. If we do, and if the current user has
-# installed the package 'bash-completion' in her $HOME/.nix-profile,
-# then completion is enabled automatically.
-if [ -f "$HOME/.nix-profile/etc/profile.d/bash_completion.sh" ]; then
-    if shopt -q progcomp &>/dev/null; then
-        . "$HOME/.nix-profile/etc/profile.d/bash_completion.sh"
-    fi
-fi
+@initBashCompletion@
 
 # Some aliases.
 alias ls="ls --color=tty"