fish: add module to support it as default shell

* Patched fish to load /etc/fish/config.fish if it exists (by default,
  it only loads config relative to itself)
* Added fish-foreign-env package to parse the system environment

closes #5331

nixos/modules/module-list.nix

@@ -64,6 +64,7 @@
   ./programs/dconf.nix
   ./programs/environment.nix
   ./programs/freetds.nix
+  ./programs/fish.nix
   ./programs/ibus.nix
   ./programs/kbdlight.nix
   ./programs/light.nix

nixos/modules/programs/fish.nix

@@ -0,0 +1,114 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfge = config.environment;
+
+  cfg = config.programs.fish;
+
+  fishAliases = concatStringsSep "\n" (
+    mapAttrsFlatten (k: v: "alias ${k} '${v}'") cfg.shellAliases
+  );
+
+in
+
+{
+
+  options = {
+
+    programs.fish = {
+
+      enable = mkOption {
+        default = false;
+        description = ''
+          Whether to configure fish as an interactive shell.
+        '';
+        type = types.bool;
+      };
+
+      shellAliases = mkOption {
+        default = config.environment.shellAliases;
+        description = ''
+          Set of aliases for fish shell. See <option>environment.shellAliases</option>
+          for an option format description.
+        '';
+        type = types.attrs;
+      };
+
+      shellInit = mkOption {
+        default = "";
+        description = ''
+          Shell script code called during fish shell initialisation.
+        '';
+        type = types.lines;
+      };
+
+      loginShellInit = mkOption {
+        default = "";
+        description = ''
+          Shell script code called during fish login shell initialisation.
+        '';
+        type = types.lines;
+      };
+
+      interactiveShellInit = mkOption {
+        default = "";
+        description = ''
+          Shell script code called during interactive fish shell initialisation.
+        '';
+        type = types.lines;
+      };
+
+      promptInit = mkOption {
+        default = "";
+        description = ''
+          Shell script code used to initialise fish prompt.
+        '';
+        type = types.lines;
+      };
+
+    };
+
+  };
+
+  config = mkIf cfg.enable {
+
+    environment.etc."fish/foreign-env/shellInit".text = cfge.shellInit;
+    environment.etc."fish/foreign-env/loginShellInit".text = cfge.loginShellInit;
+    environment.etc."fish/foreign-env/interactiveShellInit".text = cfge.interactiveShellInit;
+
+    environment.etc."fish/config.fish".text = ''
+      # /etc/fish/config.fish: DO NOT EDIT -- this file has been generated automatically.
+
+      set fish_function_path $fish_function_path ${pkgs.fish-foreign-env}/share/fish-foreign-env/functions
+
+      fenv source ${config.system.build.setEnvironment} 1> /dev/null
+      fenv source /etc/fish/foreign-env/shellInit 1> /dev/null
+
+      ${cfg.shellInit}
+
+      if builtin status --is-login
+        fenv source /etc/fish/foreign-env/loginShellInit 1> /dev/null
+        ${cfg.loginShellInit}
+      end
+
+      if builtin status --is-interactive
+        ${fishAliases}
+        fenv source /etc/fish/foreign-env/interactiveShellInit 1> /dev/null
+        ${cfg.interactiveShellInit}
+      end
+    '';
+
+    environment.systemPackages = [ pkgs.fish ];
+
+    environment.shells = [
+      "/run/current-system/sw/bin/fish"
+      "/var/run/current-system/sw/bin/fish"
+      "${pkgs.fish}/bin/fish"
+    ];
+
+  };
+
+}

pkgs/shells/fish-foreign-env/default.nix

@@ -0,0 +1,28 @@
+{ stdenv, fetchFromGitHub, gnused, bash, coreutils }:
+
+stdenv.mkDerivation rec {
+  name = "fish-foreign-env-${version}";
+  version = "git-20151223";
+
+  src = fetchFromGitHub {
+    owner = "oh-my-fish";
+    repo = "plugin-foreign-env";
+    rev = "2dfe5b73fd2101702c83d1d7b566e2b9332c5ddc";
+    sha256 = "17jxlbljp7k2azcl1miz5h5xfyazlf9z9lrddcrnm6r7c1w1zdh5";
+  };
+
+  buildCommand = ''
+    mkdir -p $out/share/fish-foreign-env/functions/
+    cp $src/functions/* $out/share/fish-foreign-env/functions/
+    sed -e "s|sed|${gnused}/bin/sed|" \
+        -e "s|bash|${bash}/bin/bash|" \
+        -e "s|\| tr|\| ${coreutils}/bin/tr|" \
+        -i $out/share/fish-foreign-env/functions/*
+  '';
+
+  meta = with stdenv.lib; {
+    description = "A foreign environment interface for Fish shell";
+    license = licenses.mit;
+    maintainers = with maintainers; [ jgillich ];
+  };
+}

pkgs/shells/fish/builtin_status.patch

@@ -0,0 +1,216 @@
+commit 5145ca56b0ac1e5e284ab6dfa6fdecc5e86e59b8
+Author: Jakob Gillich <jakob@gillich.me>
+Date:   Sat Dec 26 04:57:06 2015 +0100
+
+    prefix status command with builtin
+
+diff --git a/etc/config.fish b/etc/config.fish
+index 0683f40..9297a85 100644
+--- a/etc/config.fish
++++ b/etc/config.fish
+@@ -6,7 +6,7 @@
+ # Some things should only be done for login terminals
+ #
+ 
+-if status --is-login
++if builtin status --is-login
+ 
+ 	#
+ 	# Set some value for LANG if nothing was set before, and this is a
+diff --git a/share/functions/__fish_config_interactive.fish b/share/functions/__fish_config_interactive.fish
+index 9b27fb9..d1c704b 100644
+--- a/share/functions/__fish_config_interactive.fish
++++ b/share/functions/__fish_config_interactive.fish
+@@ -101,7 +101,7 @@ function __fish_config_interactive -d "Initializations that should be performed
+         eval "$__fish_bin_dir/fish -c 'fish_update_completions > /dev/null ^/dev/null' &"
+     end
+ 
+-	if status -i
++	if builtin status -i
+ 		#
+ 		# Print a greeting
+ 		#
+@@ -128,14 +128,14 @@ function __fish_config_interactive -d "Initializations that should be performed
+ 	#
+ 
+ 	function __fish_repaint --on-variable fish_color_cwd --description "Event handler, repaints the prompt when fish_color_cwd changes"
+-		if status --is-interactive
++		if builtin status --is-interactive
+ 			set -e __fish_prompt_cwd
+ 			commandline -f repaint ^/dev/null
+ 		end
+ 	end
+ 
+ 	function __fish_repaint_root --on-variable fish_color_cwd_root --description "Event handler, repaints the prompt when fish_color_cwd_root changes"
+-		if status --is-interactive
++		if builtin  status --is-interactive
+ 			set -e __fish_prompt_cwd
+ 			commandline -f repaint ^/dev/null
+ 		end
+@@ -191,7 +191,7 @@ function __fish_config_interactive -d "Initializations that should be performed
+ 	# Notify vte-based terminals when $PWD changes (issue #906)
+ 	if test "$VTE_VERSION" -ge 3405 -o "$TERM_PROGRAM" = "Apple_Terminal"
+ 		function __update_vte_cwd --on-variable PWD --description 'Notify VTE of change to $PWD'
+-			status --is-command-substitution; and return
++			builtin status --is-command-substitution; and return
+ 			printf '\033]7;file://%s%s\a' (hostname) (pwd | __fish_urlencode)
+ 		end
+ 	end
+diff --git a/share/functions/__fish_git_prompt.fish b/share/functions/__fish_git_prompt.fish
+index 0117894..4e4b60f 100644
+--- a/share/functions/__fish_git_prompt.fish
++++ b/share/functions/__fish_git_prompt.fish
+@@ -728,7 +728,7 @@ for var in repaint describe_style show_informative_status showdirtystate showsta
+ 	set varargs $varargs --on-variable __fish_git_prompt_$var
+ end
+ function __fish_git_prompt_repaint $varargs --description "Event handler, repaints prompt when functionality changes"
+-	if status --is-interactive
++	if builtin status --is-interactive
+ 		if test $argv[3] = __fish_git_prompt_show_informative_status
+ 			# Clear characters that have different defaults with/without informative status
+ 			for name in cleanstate dirtystate invalidstate stagedstate stateseparator untrackedfiles upstream_ahead upstream_behind
+@@ -746,7 +746,7 @@ for var in '' _prefix _suffix _bare _merging _cleanstate _invalidstate _upstream
+ end
+ set varargs $varargs --on-variable __fish_git_prompt_showcolorhints
+ function __fish_git_prompt_repaint_color $varargs --description "Event handler, repaints prompt when any color changes"
+-	if status --is-interactive
++	if builtin status --is-interactive
+ 		set -l var $argv[3]
+ 		set -e _$var
+ 		set -e _{$var}_done
+@@ -766,7 +766,7 @@ for var in cleanstate dirtystate invalidstate stagedstate stashstate statesepara
+ 	set varargs $varargs --on-variable __fish_git_prompt_char_$var
+ end
+ function __fish_git_prompt_repaint_char $varargs --description "Event handler, repaints prompt when any char changes"
+-	if status --is-interactive
++	if builtin status --is-interactive
+ 		set -e _$argv[3]
+ 		commandline -f repaint ^/dev/null
+ 	end
+diff --git a/share/functions/cd.fish b/share/functions/cd.fish
+index 8faa469..10168d7 100644
+--- a/share/functions/cd.fish
++++ b/share/functions/cd.fish
+@@ -5,7 +5,7 @@
+ function cd --description "Change directory"
+ 
+ 	# Skip history in subshells
+-	if status --is-command-substitution
++	if builtin status --is-command-substitution
+ 		builtin cd $argv
+ 		return $status
+ 	end
+@@ -33,4 +33,3 @@ function cd --description "Change directory"
+ 
+ 	return $cd_status
+ end
+-
+diff --git a/share/functions/eval.fish b/share/functions/eval.fish
+index 052d417..5eeb12a 100644
+--- a/share/functions/eval.fish
++++ b/share/functions/eval.fish
+@@ -23,17 +23,17 @@ function eval -S -d "Evaluate parameters as a command"
+ 	# used interactively, like less, wont work using eval.
+ 
+ 	set -l mode
+-	if status --is-interactive-job-control
++	if builtin status --is-interactive-job-control
+ 		set mode interactive
+ 	else
+-		if status --is-full-job-control
++		if builtin status --is-full-job-control
+ 			set mode full
+ 		else
+ 			set mode none
+ 		end
+ 	end
+-	if status --is-interactive
+-		status --job-control full
++	if builtin status --is-interactive
++		builtin status --job-control full
+ 	end
+ 	__fish_restore_status $status_copy
+ 
+@@ -60,6 +60,6 @@ function eval -S -d "Evaluate parameters as a command"
+ 	echo "begin; $argv "\n" ;end <&3 3<&-" | source 3<&0
+ 	set -l res $status
+ 
+-	status --job-control $mode
++	builtin status --job-control $mode
+ 	return $res
+ end
+diff --git a/share/functions/history.fish b/share/functions/history.fish
+index fd2b91f..12d28d7 100644
+--- a/share/functions/history.fish
++++ b/share/functions/history.fish
+@@ -38,7 +38,7 @@ function history --description "Deletes an item from history"
+         end
+     else
+         #Execute history builtin without any argument
+-        if status --is-interactive
++        if builtin status --is-interactive
+             builtin history | eval $pager
+         else
+             builtin history
+diff --git a/share/functions/psub.fish b/share/functions/psub.fish
+index 67863ad..dd0e08b 100644
+--- a/share/functions/psub.fish
++++ b/share/functions/psub.fish
+@@ -40,7 +40,7 @@ function psub --description "Read from stdin into a file and output the filename
+ 
+ 	end
+ 
+-	if not status --is-command-substitution
++	if not builtin status --is-command-substitution
+ 		echo psub: Not inside of command substitution >&2
+ 		return 1
+ 	end
+diff --git a/share/tools/web_config/sample_prompts/classic_git.fish b/share/tools/web_config/sample_prompts/classic_git.fish
+index 39f3ab8..601fa19 100644
+--- a/share/tools/web_config/sample_prompts/classic_git.fish
++++ b/share/tools/web_config/sample_prompts/classic_git.fish
+@@ -17,25 +17,25 @@ function fish_prompt --description 'Write out the prompt'
+ 		set -g __fish_classic_git_functions_defined
+ 
+ 		function __fish_repaint_user --on-variable fish_color_user --description "Event handler, repaint when fish_color_user changes"
+-			if status --is-interactive
++			if builtin status --is-interactive
+ 				commandline -f repaint ^/dev/null
+ 			end
+ 		end
+-		
++
+ 		function __fish_repaint_host --on-variable fish_color_host --description "Event handler, repaint when fish_color_host changes"
+-			if status --is-interactive
++			if builtin status --is-interactive
+ 				commandline -f repaint ^/dev/null
+ 			end
+ 		end
+-		
++
+ 		function __fish_repaint_status --on-variable fish_color_status --description "Event handler; repaint when fish_color_status changes"
+-			if status --is-interactive
++			if builtin status --is-interactive
+ 				commandline -f repaint ^/dev/null
+ 			end
+ 		end
+ 
+ 		function __fish_repaint_bind_mode --on-variable fish_key_bindings --description "Event handler; repaint when fish_key_bindings changes"
+-			if status --is-interactive
++			if builtin status --is-interactive
+ 				commandline -f repaint ^/dev/null
+ 			end
+ 		end
+diff --git a/tests/test_util.fish b/tests/test_util.fish
+index 22744b3..576dbc4 100644
+--- a/tests/test_util.fish
++++ b/tests/test_util.fish
+@@ -4,7 +4,7 @@
+ if test "$argv[1]" = (status -f)
+     echo 'test_util.fish requires sourcing script as argument to `source`' >&2
+     echo 'use `source test_util.fish (status -f); or exit`' >&2
+-    status --print-stack-trace >&2
++    builtin status --print-stack-trace >&2
+     exit 1
+ end
+ 

pkgs/shells/fish/default.nix

@@ -1,4 +1,5 @@
-{ stdenv, fetchurl, ncurses, nettools, python, which, groff, gettext, man_db, bc, libiconv, coreutils }:
+{ stdenv, fetchurl, ncurses, nettools, python, which, groff, gettext, man_db,
+  bc, libiconv, coreutils, gnused, kbd }:
 
 stdenv.mkDerivation rec {
   name = "fish-${version}";
@@ -9,6 +10,9 @@ stdenv.mkDerivation rec {
     sha256 = "0ympqz7llmf0hafxwglykplw6j5cz82yhlrw50lw4bnf2kykjqx7";
   };
 
+  # builtin_status has been upstreamed https://github.com/fish-shell/fish-shell/pull/2636
+  patches = [ ./etc_config.patch ./builtin_status.patch ];
+
   buildInputs = [ ncurses libiconv ];
 
   # Required binaries during execution
@@ -18,15 +22,26 @@ stdenv.mkDerivation rec {
                           ++ [ bc coreutils ];
 
   postInstall = ''
+    sed -e "s|expr|${coreutils}/bin/expr|" \
+        -e "s|if which unicode_start|if true|" \
+        -e "s|unicode_start|${kbd}/bin/unicode_start|" \
+        -i "$out/etc/fish/config.fish"
     sed -e "s|bc|${bc}/bin/bc|" \
         -e "s|/usr/bin/seq|${coreutils}/bin/seq|" \
         -i "$out/share/fish/functions/seq.fish" \
            "$out/share/fish/functions/math.fish"
     sed -i "s|which |${which}/bin/which |" "$out/share/fish/functions/type.fish"
+    sed -e "s|\|cut|\|${coreutils}/bin/cut|" -i "$out/share/fish/functions/fish_prompt.fish"
     sed -i "s|nroff |${groff}/bin/nroff |" "$out/share/fish/functions/__fish_print_help.fish"
     sed -e "s|gettext |${gettext}/bin/gettext |" \
         -e "s|which |${which}/bin/which |" \
         -i "$out/share/fish/functions/_.fish"
+    sed -e "s|uname|${coreutils}/bin/uname|" \
+        -i "$out/share/fish/functions/__fish_pwd.fish" \
+           "$out/share/fish/functions/prompt_pwd.fish"
+    sed -e "s|sed |${gnused}/bin/sed |" \
+        -i "$out/share/fish/functions/alias.fish" \
+           "$out/share/fish/functions/prompt_pwd.fish"
     substituteInPlace "$out/share/fish/functions/fish_default_key_bindings.fish" \
       --replace "clear;" "${ncurses}/bin/clear;"
   '' + stdenv.lib.optionalString (!stdenv.isDarwin) ''

pkgs/shells/fish/etc_config.patch

@@ -0,0 +1,17 @@
+commit 0ec07a7018bd69513b0bca6e2f22dbf8575a5b5e
+Author: Jakob Gillich <jakob@gillich.me>
+Date:   Fri Dec 25 01:59:29 2015 +0100
+
+    load /etc/fish/config.fish if it exists
+
+diff --git a/etc/config.fish b/etc/config.fish
+index 0683f40..33f4da7 100644
+--- a/etc/config.fish
++++ b/etc/config.fish
+@@ -37,3 +37,6 @@ if status --is-login
+        end
+ end
+
++if test -f /etc/fish/config.fish
++  source /etc/fish/config.fish
++end

pkgs/top-level/all-packages.nix

@@ -3737,6 +3737,8 @@ let
     python = python27Full;
   };
 
+  fish-foreign-env = callPackage ../shells/fish-foreign-env { };
+
   mksh = callPackage ../shells/mksh { };
 
   pash = callPackage ../shells/pash { };