[bug#49828] [PATCH 02/20] gnu: minetest: Search for mods in MINETEST_MOD_PATH.

[Maxime Devos]

* gnu/packages/patches/Add-environment-variable-MINETEST_MOD_PATH.patch:
  New file.
* gnu/packages/games.scm
  (minetest)[source]{patches}: Add it.
  (minetest)[native-search-paths]: Add "MINETEST_MOD_PATH".
* gnu/local.mk (dist_patch_DATA): Add the patch.
---
 gnu/local.mk                                  |   1 +
 gnu/packages/games.scm                        |   7 +-
 ...vironment-variable-MINETEST_MOD_PATH.patch | 115 ++++++++++++++++++
 3 files changed, 122 insertions(+), 1 deletion(-)
 create mode 100644 
gnu/packages/patches/Add-environment-variable-MINETEST_MOD_PATH.patch

diff --git a/gnu/local.mk b/gnu/local.mk
index c80a9af78c..d96d4e3dbc 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -801,6 +801,7 @@ dist_patch_DATA =                                           
\
   %D%/packages/patches/abseil-cpp-fix-gtest.patch              \
   %D%/packages/patches/abseil-cpp-fix-strerror_test.patch      \
   %D%/packages/patches/adb-add-libraries.patch                 \
+  %D%/packages/patches/Add-environment-variable-MINETEST_MOD_PATH.patch        
\
   %D%/packages/patches/aegis-constness-error.patch             \
   %D%/packages/patches/aegis-perl-tempdir1.patch               \
   %D%/packages/patches/aegis-perl-tempdir2.patch               \
diff --git a/gnu/packages/games.scm b/gnu/packages/games.scm
index 3e7086b398..2f3285c6ea 100644
--- a/gnu/packages/games.scm
+++ b/gnu/packages/games.scm
@@ -3553,6 +3553,7 @@ match, cannon keep, and grave-itation pit.")
                (base32
                 "062ilb7s377q3hwfhl8q06vvcw2raydz5ljzlzwy2dmyzmdcndb8"))
               (modules '((guix build utils)))
+              (patches (search-patches 
"Add-environment-variable-MINETEST_MOD_PATH.patch"))
               (snippet
                '(begin
                   ;; Delete bundled libraries.
@@ -3599,7 +3600,11 @@ match, cannon keep, and grave-itation pit.")
     (native-search-paths
      (list (search-path-specification
             (variable "MINETEST_SUBGAME_PATH")
-            (files '("share/minetest/games")))))
+            (files '("share/minetest/games")))
+           (search-path-specification
+            (variable "MINETEST_MOD_PATH")
+            (files '("share/minetest/mods"))
+            (separator #f))))
     (native-inputs
      `(("pkg-config" ,pkg-config)))
     (inputs
diff --git 
a/gnu/packages/patches/Add-environment-variable-MINETEST_MOD_PATH.patch 
b/gnu/packages/patches/Add-environment-variable-MINETEST_MOD_PATH.patch
new file mode 100644
index 0000000000..8478a7bf72
--- /dev/null
+++ b/gnu/packages/patches/Add-environment-variable-MINETEST_MOD_PATH.patch
@@ -0,0 +1,115 @@
+From 6eb753c5bf67764890856cf23a67c0bf65973c16 Mon Sep 17 00:00:00 2001
+From: Maxime Devos <maximedevos@telenet.be>
+Date: Thu, 29 Jul 2021 22:24:50 +0200
+Subject: [PATCH] Add environment variable MINETEST_MOD_PATH
+
+This adds an environment variable MINETEST_MOD_PATH.
+When it exists, Minetest will look there for mods
+in addition to ~/.minetest/mods/.
+
+This patch as-is is not yet ready for upstream, because:
+
+  * the GUI will only display mods in MINETEST_MOD_PATH
+    or mods in ~/.minetest/mods, it won't combine the two
+
+  * the GUI for installing mods from ContentDB is disabled
+    when MINETEST_MOD_PATH is set, because otherwise Minetest
+    would try to install mods in the store.
+
+  * MINETEST_MOD_PATH can only have a single component
+---
+ builtin/mainmenu/dlg_contentstore.lua |  7 +++++++
+ src/content/subgames.cpp              |  3 +++
+ src/script/lua_api/l_mainmenu.cpp     | 14 +++++++++++++-
+ src/script/lua_api/l_mainmenu.h       |  2 ++
+ 4 files changed, 25 insertions(+), 1 deletion(-)
+
+diff --git a/builtin/mainmenu/dlg_contentstore.lua 
b/builtin/mainmenu/dlg_contentstore.lua
+index 7096c9187..c4a2cbd18 100644
+--- a/builtin/mainmenu/dlg_contentstore.lua
++++ b/builtin/mainmenu/dlg_contentstore.lua
+@@ -22,6 +22,13 @@ if not core.get_http_api then
+       end
+       return
+ end
++if core.mod_path_set() then
++      function create_store_dlg()
++              return messagebox("store",
++                              fgettext("Mods from ContentDB cannot be 
installed when mods from Guix are also installed"))
++      end
++      return
++end
+ 
+ -- Unordered preserves the original order of the ContentDB API,
+ -- before the package list is ordered based on installed state.
+diff --git a/src/content/subgames.cpp b/src/content/subgames.cpp
+index e9dc609b0..1809f189e 100644
+--- a/src/content/subgames.cpp
++++ b/src/content/subgames.cpp
+@@ -110,6 +110,9 @@ SubgameSpec findSubgame(const std::string &id)
+       std::set<std::string> mods_paths;
+       if (!user_game)
+               mods_paths.insert(share + DIR_DELIM + "mods");
++      const char *env_mod_path = getenv("MINETEST_MOD_PATH");
++      if (env_mod_path)
++              mods_paths.insert(std::string(env_mod_path));
+       if (user != share || user_game)
+               mods_paths.insert(user + DIR_DELIM + "mods");
+ 
+diff --git a/src/script/lua_api/l_mainmenu.cpp 
b/src/script/lua_api/l_mainmenu.cpp
+index ad00de1c4..737550c42 100644
+--- a/src/script/lua_api/l_mainmenu.cpp
++++ b/src/script/lua_api/l_mainmenu.cpp
+@@ -495,9 +495,19 @@ int ModApiMainMenu::l_get_user_path(lua_State *L)
+ 
/******************************************************************************/
+ int ModApiMainMenu::l_get_modpath(lua_State *L)
+ {
++      const char *c_modpath = getenv("MINETEST_MOD_PATH");
+       std::string modpath = fs::RemoveRelativePathComponents(
+               porting::path_user + DIR_DELIM + "mods" + DIR_DELIM);
+-      lua_pushstring(L, modpath.c_str());
++      if (c_modpath == NULL)
++              c_modpath = modpath.c_str();
++      lua_pushstring(L, c_modpath);
++      return 1;
++}
++
++/******************************************************************************/
++int ModApiMainMenu::l_mod_path_set(lua_State *L)
++{
++      lua_pushboolean(L, NULL != getenv("MINETEST_MOD_PATH"));
+       return 1;
+ }
+ 
+@@ -855,6 +865,7 @@ void ModApiMainMenu::Initialize(lua_State *L, int top)
+       API_FCT(get_mapgen_names);
+       API_FCT(get_user_path);
+       API_FCT(get_modpath);
++      API_FCT(mod_path_set);
+       API_FCT(get_clientmodpath);
+       API_FCT(get_gamepath);
+       API_FCT(get_texturepath);
+@@ -888,6 +899,7 @@ void ModApiMainMenu::InitializeAsync(lua_State *L, int top)
+       API_FCT(get_mapgen_names);
+       API_FCT(get_user_path);
+       API_FCT(get_modpath);
++      API_FCT(mod_path_set);
+       API_FCT(get_clientmodpath);
+       API_FCT(get_gamepath);
+       API_FCT(get_texturepath);
+diff --git a/src/script/lua_api/l_mainmenu.h b/src/script/lua_api/l_mainmenu.h
+index ec2d20da2..719c26077 100644
+--- a/src/script/lua_api/l_mainmenu.h
++++ b/src/script/lua_api/l_mainmenu.h
+@@ -112,6 +112,8 @@ class ModApiMainMenu: public ModApiBase
+ 
+       static int l_get_modpath(lua_State *L);
+ 
++      static int l_mod_path_set(lua_State *L);
++
+       static int l_get_clientmodpath(lua_State *L);
+ 
+       static int l_get_gamepath(lua_State *L);
+-- 
+2.32.0
+
-- 
2.32.0