vimPlugins: split doc generation into a hook

so that the hook can be used for lua modules as well. Improves
composition.

pkgs/misc/vim-plugins/build-vim-plugin.nix

@@ -1,6 +1,7 @@
 { lib, stdenv
-, rtpPath ? "share/vim-plugins"
+, rtpPath
 , vim
+, vimGenDocHook
 }:
 
 rec {
@@ -25,6 +26,7 @@ rec {
     addRtp "${rtpPath}/${path}" attrs (stdenv.mkDerivation (attrs // {
       name = namePrefix + name;
 
+      nativeBuildInputs = attrs.nativeBuildInputs or [] ++ [ vimGenDocHook ];
       inherit unpackPhase configurePhase buildPhase addonInfo preInstall postInstall;
 
       installPhase = ''
@@ -34,21 +36,6 @@ rec {
         mkdir -p $out/${rtpPath}
         cp -r . $target
 
-        # build help tags
-        if [ -d "$target/doc" ]; then
-          echo "Building help tags"
-          if ! ${vim}/bin/vim -N -u NONE -i NONE -n -E -s -V1 -c "helptags $target/doc" +quit!; then
-            echo "Failed to build help tags!"
-            exit 1
-          fi
-        else
-          echo "No docs available"
-        fi
-
-        if [ -n "$addonInfo" ]; then
-          echo "$addonInfo" > $target/addon-info.json
-        fi
-
         runHook postInstall
       '';
     }));

pkgs/misc/vim-plugins/default.nix

@@ -3,7 +3,7 @@
 
 let
 
-  inherit (vimUtils.override {inherit vim;}) buildVimPluginFrom2Nix;
+  inherit (vimUtils.override {inherit vim;}) buildVimPluginFrom2Nix vimGenDocHook;
 
   inherit (lib) extends;
 
@@ -11,6 +11,8 @@ let
     # Convert derivation to a vim plugin.
     toVimPlugin = drv:
       drv.overrideAttrs(oldAttrs: {
+
+        nativeBuildInputs = oldAttrs.nativeBuildInputs or [] ++ [ vimGenDocHook ];
         passthru = (oldAttrs.passthru or {}) // {
           vimPlugin = true;
         };

pkgs/misc/vim-plugins/update-shell.nix

@@ -0,0 +1,13 @@
+{ nixpkgs ? import ../../.. { } }:
+with nixpkgs;
+let
+  pyEnv = python3.withPackages(ps: [ ps.GitPython ]);
+in
+mkShell {
+  packages = [
+    bash
+    pyEnv
+    nix-prefetch-scripts
+  ];
+}
+

pkgs/misc/vim-plugins/update.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env nix-shell
-#!nix-shell -p nix-prefetch-git -p python3 -p python3Packages.GitPython nix -i python3
+#!nix-shell update-shell.nix -i python3
+
 
 # format:
 # $ nix run nixpkgs.python3Packages.black -c black update.py

pkgs/misc/vim-plugins/vim-gen-doc-hook.sh

@@ -0,0 +1,31 @@
+echo "Sourcing vim-gen-doc-hook"
+
+# the doc folder is copied via the copy_directories entry of the rockspec
+# in the folder gitsigns.nvim-scm-1-rocks/gitsigns.nvim/scm-1
+vimPluginGenTags() {
+    echo "Executing vimPluginGenTags"
+
+    target="$out/@rtpPath@/$pname"
+    mkdir -p $out/@rtpPath@
+    cp -r . $target
+
+    # build help tags
+    if [ -d "$target/doc" ]; then
+        echo "Building help tags"
+        if ! @vimBinary@ -N -u NONE -i NONE -n -E -s -V1 -c "helptags $target/doc" +quit!; then
+        echo "Failed to build help tags!"
+        exit 1
+        fi
+    else
+        echo "No docs available"
+    fi
+
+    if [ -n "$addonInfo" ]; then
+        echo "$addonInfo" > $target/addon-info.json
+    fi
+
+    echo "Finished executing vimPluginInstallPhase"
+}
+
+preFixupHooks+=(vimPluginGenTags)
+

pkgs/misc/vim-plugins/vim-utils.nix

@@ -4,6 +4,7 @@
 , fetchFromGitHub, runtimeShell
 , hasLuaModule
 , python3
+, callPackage, makeSetupHook
 }:
 
 /*
@@ -485,7 +486,18 @@ rec {
     '';
   };
 
-  inherit (import ./build-vim-plugin.nix { inherit lib stdenv rtpPath vim; }) buildVimPlugin buildVimPluginFrom2Nix;
+  vimGenDocHook = callPackage ({ vim }:
+    makeSetupHook {
+      name = "vim-gen-doc-hook";
+      deps = [ vim ];
+      substitutions = {
+        vimBinary = "${vim}/bin/vim";
+        inherit rtpPath;
+      };
+    } ./vim-gen-doc-hook.sh) {};
+
+  inherit (import ./build-vim-plugin.nix { inherit lib stdenv rtpPath vim vimGenDocHook; })
+    buildVimPlugin buildVimPluginFrom2Nix;
 
   # used to figure out which python dependencies etc. neovim needs
   requiredPlugins = {