neovim: pass packpath via the wrapper

Adding "packages" to the neovim distribution triggers the wrapping of
the derivation. This is because it tries to "set packpath/rtp" in the
init.vim.

If we set these arguments via --cmd instead we can avoid to create an
init.vim, which can be useful if we want to wrap an init.lua later on
(in home-manager for instance, we dont want to generate viml code).

Also removes the support for "configure" in makeNeovimConfig and
configure.plug / configure.vam packages in the compatibility layer
'legacyWrapper'.

pkgs/applications/editors/neovim/neovim-override.vim

@@ -1,7 +1 @@
-" configuration generated by NIX
-set nocompatible
-
-set packpath^=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-vim-pack-dir
-set runtimepath^=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-vim-pack-dir
-
 :help ale

pkgs/applications/editors/neovim/tests.nix

@@ -86,9 +86,11 @@ rec {
 
   nvim_with_plug = neovim.override {
     extraName = "-with-plug";
-    configure.plug.plugins = with pkgs.vimPlugins; [
-      (base16-vim.overrideAttrs(old: { pname = old.pname + "-unique-for-tests-please-dont-use"; }))
-    ];
+    configure.packages.plugins = with pkgs.vimPlugins; {
+      start = [
+        (base16-vim.overrideAttrs(old: { pname = old.pname + "-unique-for-tests-please-dont-use"; }))
+      ];
+    };
     configure.customRC = ''
       color base16-tomorrow-night
       set background=dark
@@ -123,7 +125,7 @@ rec {
   });
 
   force-nowrap = runTest nvimDontWrap ''
-      ! grep "-u" ${nvimDontWrap}/bin/nvim
+      ! grep -F -- ' -u' ${nvimDontWrap}/bin/nvim
   '';
 
   nvim_via_override-test = runTest nvim_via_override ''

pkgs/applications/editors/neovim/utils.nix

@@ -11,15 +11,16 @@
 , wrapNeovimUnstable
 }:
 let
-  # returns everything needed for the caller to wrap its own neovim:
-  # - the generated content of the future init.vim
-  # - the arguments to wrap neovim with
-  # The caller is responsible for writing the init.vim and adding it to the wrapped
-  # arguments (["-u" writeText "init.vim" GENERATEDRC)]).
-  # This makes it possible to write the config anywhere: on a per-project basis
-  # .nvimrc or in $XDG_CONFIG_HOME/nvim/init.vim to avoid sideeffects.
-  # Indeed, note that wrapping with `-u init.vim` has sideeffects like .nvimrc wont be loaded
-  # anymore, $MYVIMRC wont be set etc
+   /* returns everything needed for the caller to wrap its own neovim:
+   - the generated content of the future init.vim
+   - the arguments to wrap neovim with
+   The caller is responsible for writing the init.vim and adding it to the wrapped
+   arguments (["-u" writeText "init.vim" GENERATEDRC)]).
+   This makes it possible to write the config anywhere: on a per-project basis
+   .nvimrc or in $XDG_CONFIG_HOME/nvim/init.vim to avoid sideeffects.
+   Indeed, note that wrapping with `-u init.vim` has sideeffects like .nvimrc wont be loaded
+   anymore, $MYVIMRC wont be set etc
+   */
   makeNeovimConfig =
     {
     withPython2 ? false
@@ -36,10 +37,8 @@ let
     # expects a list of plugin configuration
     # expects { plugin=far-vim; config = "let g:far#source='rg'"; optional = false; }
     , plugins ? []
-    # forwarded to configure.customRC
+    # custom viml config appended after plugin-specific config
     , customRC ? ""
-    # same values as in vimUtils.vimrcContent (deprecated)
-    , configure ? { }
 
     # for forward compability, when adding new environments, haskell etc.
     , ...
@@ -54,25 +53,20 @@ let
       };
 
       # transform all plugins into an attrset
-      pluginsNormalized = map (x: if x ? plugin then { optional = false; } // x else { plugin = x; optional = false;}) plugins;
+      # { optional = bool; plugin = package; dest = filename; }
+      pluginsNormalized = map (x: if x ? plugin then { dest = "init.vim"; optional = false; } // x else { plugin = x; optional = false;}) plugins;
 
 
-      configurePatched = configure // {
-        customRC = pluginRc + customRC + (configure.customRC or "");
-      };
 
-      # A function to get the configuration string (if any) from an element of 'plugins'
-      pluginConfig = p:
-        if (p.config or "") != "" then ''
-          " ${p.plugin.pname or p.plugin.name} {{{
-          ${p.config}
-          " }}}
-        '' else "";
+      pluginRC = lib.concatMapStrings (p: p.config or "") pluginsNormalized;
 
-      pluginRc = lib.concatMapStrings pluginConfig pluginsNormalized;
-
-      requiredPlugins = vimUtils.requiredPlugins configurePatched;
+      pluginsPartitioned = lib.partition (x: x.optional == true) pluginsNormalized;
+      requiredPlugins = vimUtils.requiredPluginsForPackage myVimPackage;
       getDeps = attrname: map (plugin: plugin.${attrname} or (_: [ ]));
+      myVimPackage = {
+            start = map (x: x.plugin) pluginsPartitioned.wrong;
+            opt = map (x: x.plugin) pluginsPartitioned.right;
+      };
 
       pluginPython3Packages = getDeps "python3Dependencies" requiredPlugins;
       python3Env = python3Packages.python.withPackages (ps:
@@ -102,8 +96,16 @@ let
         let
           binPath = lib.makeBinPath (lib.optionals withRuby [ rubyEnv ] ++ lib.optionals withNodeJs [ nodejs ]);
 
+          hostProviderViml = lib.mapAttrsToList genProviderSettings hostprog_check_table;
+
+          # as expected by packdir
+          packDirArgs.myNeovimPackages = myVimPackage;
+
           # vim accepts a limited number of commands so we join them all
-          flags =  [ "--cmd" (lib.intersperse "|" (lib.mapAttrsToList genProviderSettings hostprog_check_table)) ];
+          flags = [
+            "--cmd" (lib.intersperse "|" hostProviderViml)
+            "--cmd" "set packpath^=${vimUtils.packDir packDirArgs}"
+            ];
         in
         [
           "--inherit-argv0" "--add-flags" (lib.escapeShellArgs flags)
@@ -116,9 +118,9 @@ let
           "--prefix" "LUA_CPATH" ";" (neovim-unwrapped.lua.pkgs.lib.genLuaCPathAbsStr luaEnv)
         ];
 
-
-      manifestRc = vimUtils.vimrcContent (configurePatched // { customRC = ""; }) ;
-      neovimRcContent = vimUtils.vimrcContent configurePatched;
+      manifestRc = vimUtils.vimrcContent ({ customRC = ""; }) ;
+      # we call vimrcContent without 'packages' to avoid the init.vim generation
+      neovimRcContent = vimUtils.vimrcContent ({ beforePlugins = ""; customRC = pluginRC + customRC; packages = null; });
     in
     assert withPython2 -> throw "Python2 support has been removed from neovim, please remove withPython2 and extraPython2Packages.";
 
@@ -140,7 +142,7 @@ let
         "let g:loaded_${prog}_provider=0"
     ;
 
-  # to keep backwards compatibility
+  # to keep backwards compatibility for people using neovim.override
   legacyWrapper = neovim: {
     extraMakeWrapperArgs ? ""
     , withPython ? false
@@ -163,12 +165,21 @@ let
         (_: lib.warn "passing a list as extraPythonPackages to the neovim wrapper is deprecated, pass a function as to python.withPackages instead" funOrList)
       else funOrList);
 
+      # we convert from the old configure.format to
+      plugins = if builtins.hasAttr "plug" configure then
+          throw "The neovim legacy wrapper doesn't support configure.plug anymore, please setup your plugins via 'configure.packages' instead"
+        else
+          lib.flatten (lib.mapAttrsToList genPlugin (configure.packages or {}));
+      genPlugin = packageName: {start ? [], opt?[]}:
+        start ++ opt;
+
       res = makeNeovimConfig {
         inherit withPython3;
         extraPython3Packages = compatFun extraPython3Packages;
         inherit extraLuaPackages;
         inherit withNodeJs withRuby viAlias vimAlias;
-        inherit configure;
+        customRC = configure.customRC or "";
+        inherit plugins;
         inherit extraName;
       };
     in

pkgs/applications/editors/vim/plugins/vim-utils.nix

@@ -236,7 +236,7 @@ let
    */
   vimrcContent = {
     packages ? null,
-    vam ? null,
+    vam ? null, # deprecated
     pathogen ? null, # deprecated
     plug ? null,
     beforePlugins ? ''