[PATCH] gtk+: Support GUIX_GTK{2,3}_PATH variables.

[Ricardo Wurmus]

Hi Guix,

a couple of months ago we discussed how to make IBus and GTK themes work
across different GTK versions.

See:

  http://lists.gnu.org/archive/html/guix-devel/2015-09/msg00617.html

To summarise, GTK itself only supports path environment variables that
are recognised by *all* versions of GTK, such as GTK_EXE_PREFIX or
GTK_PATH.  This is a problem as modules built for GTK3 cannot be loaded
by GTK2 (and vice versa).  This can result in segfaults or other nasty
effects that are hard to debug.

The attached patches modify our gtk packages such that they apply
patches against the GTK sources to enable support for two new
environment variables:

  * GUIX_GTK2_PATH, which is honoured exclusively by gtk+ 2.x, and
  * GUIX_GTK3_PATH, which is only honoured by gtk+ 3.x

Directories specified in these variables are searched first when GTK
looks for modules, such as input method modules provided by IBus.  A
user would just set both of these variables such:

   export GUIX_GTK2_PATH=$HOME/.guix-profile/lib/gtk-2.0
   export GUIX_GTK3_PATH=$HOME/.guix-profile/lib/gtk-3.0

With these variables set GTK2 will find the IBus input methods for GTK2
(and not those for GTK3), and vice versa.

I rebuilt both GTKs in my profile, and rebuilt ibus, ibus-libpinyin, and
xfce4-terminal and after removing some cached state (a problem which
we’ll have to fix eventually) I could input Chinese characters on the
terminal, indicating that the environment variables are in fact
recognised.

An additional patch to ibus-libpinyin was required because it previously
only worked by accident as I had a package installed in my profile that
also propagated gtk+.  The third attached patch adds gtk-propagated
inputs to ibus-libpinyin for the sole purpose of adding their
girepository directories to the GI_TYPELIB_PATH with which we’re
wrapping some executables.

>From 87b0a54e92f51b885ea93ebc3e05c78fcfb94dcf Mon Sep 17 00:00:00 2001
From: Ricardo Wurmus <address@hidden>
Date: Thu, 3 Dec 2015 08:30:04 +0100
Subject: [PATCH 1/3] gnu: gtk+-2: Add patch to support GUIX_GTK2_PATH.

* gnu/packages/patches/gtk2-respect-GUIX_GTK2_PATH: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/gtk.scm (gtk+-2) [source]: Add patch.
[native-search-paths]: Add search path for GUIX_GTK2_PATH.
---
 gnu-system.am                                      |  1 +
 gnu/packages/gtk.scm                               |  9 ++++-
 .../patches/gtk2-respect-GUIX_GTK2_PATH.patch      | 46 ++++++++++++++++++++++
 3 files changed, 54 insertions(+), 2 deletions(-)
 create mode 100644 gnu/packages/patches/gtk2-respect-GUIX_GTK2_PATH.patch

diff --git a/gnu-system.am b/gnu-system.am
index 4e06853..677ade5 100644
--- a/gnu-system.am
+++ b/gnu-system.am
@@ -505,6 +505,7 @@ dist_patch_DATA =                                           
\
   gnu/packages/patches/guile-present-coding.patch              \
   gnu/packages/patches/guile-relocatable.patch                 \
   gnu/packages/patches/guile-rsvg-pkgconfig.patch              \
+  gnu/packages/patches/gtk2-respect-GUIX_GTK2_PATH.patch       \
   gnu/packages/patches/gtkglext-disable-disable-deprecated.patch \
   gnu/packages/patches/hop-bigloo-4.0b.patch                   \
   gnu/packages/patches/hop-linker-flags.patch                  \
diff --git a/gnu/packages/gtk.scm b/gnu/packages/gtk.scm
index c0c0794..33feb2a 100644
--- a/gnu/packages/gtk.scm
+++ b/gnu/packages/gtk.scm
@@ -522,7 +522,8 @@ is part of the GNOME accessibility project.")
                                 name "-" version ".tar.xz"))
             (sha256
              (base32
-              "0mj6xn40py9r9lvzg633fal81xfwfm89d9mvz7jk4lmwk0g49imj"))))
+              "0mj6xn40py9r9lvzg633fal81xfwfm89d9mvz7jk4lmwk0g49imj"))
+            (patches (list (search-patch 
"gtk2-respect-GUIX_GTK2_PATH.patch")))))
    (build-system gnu-build-system)
    (outputs '("out" "doc"))
    (propagated-inputs
@@ -557,7 +558,11 @@ is part of the GNOME accessibility project.")
          ;; FIXME: re-enable tests requiring an X server
          (substitute* "gtk/Makefile.in"
            (("SUBDIRS = theme-bits . tests") "SUBDIRS = theme-bits .")))
-      %standard-phases)))
+       %standard-phases)))
+   (native-search-paths
+    (list (search-path-specification
+           (variable "GUIX_GTK2_PATH")
+           (files '("lib/gtk-2.0")))))
    (synopsis "Cross-platform toolkit for creating graphical user interfaces")
    (description
     "GTK+, or the GIMP Toolkit, is a multi-platform toolkit for creating
diff --git a/gnu/packages/patches/gtk2-respect-GUIX_GTK2_PATH.patch 
b/gnu/packages/patches/gtk2-respect-GUIX_GTK2_PATH.patch
new file mode 100644
index 0000000..93a8ddc
--- /dev/null
+++ b/gnu/packages/patches/gtk2-respect-GUIX_GTK2_PATH.patch
@@ -0,0 +1,46 @@
+This patch makes GTK+ look for additional modules in a list of directories
+specified by the environment variable "GUIX_GTK2_PATH".  This can be used
+instead of "GTK_PATH" to make GTK+ find modules that are incompatible with
+other major versions of GTK+.
+
+--- a/gtk/gtkmodules.c 2014-09-29 22:02:17.000000000 +0200
++++ b/gtk/gtkmodules.c 2015-12-02 18:41:53.306396938 +0100
+@@ -55,6 +55,7 @@
+ get_module_path (void)
+ {
+   const gchar *module_path_env;
++  const gchar *module_guix_gtk2_path_env;
+   const gchar *exe_prefix;
+   const gchar *home_dir;
+   gchar *home_gtk_dir = NULL;
+@@ -70,6 +71,7 @@
+     home_gtk_dir = g_build_filename (home_dir, ".gtk-2.0", NULL);
+ 
+   module_path_env = g_getenv ("GTK_PATH");
++  module_guix_gtk2_path_env = g_getenv ("GUIX_GTK2_PATH");
+   exe_prefix = g_getenv ("GTK_EXE_PREFIX");
+ 
+   if (exe_prefix)
+@@ -77,9 +79,21 @@
+   else
+     default_dir = g_build_filename (GTK_LIBDIR, "gtk-2.0", NULL);
+ 
+-  if (module_path_env && home_gtk_dir)
++  if (module_guix_gtk2_path_env && module_path_env && home_gtk_dir)
++    module_path = g_build_path (G_SEARCHPATH_SEPARATOR_S,
++                              module_guix_gtk2_path_env, module_path_env, 
home_gtk_dir, default_dir, NULL);
++  else if (module_guix_gtk2_path_env && home_gtk_dir)
++    module_path = g_build_path (G_SEARCHPATH_SEPARATOR_S,
++                              module_guix_gtk2_path_env, home_gtk_dir, 
default_dir, NULL);
++  else if (module_guix_gtk2_path_env && module_path_env)
++    module_path = g_build_path (G_SEARCHPATH_SEPARATOR_S,
++                              module_guix_gtk2_path_env, module_path_env, 
default_dir, NULL);
++  else if (module_path_env && home_gtk_dir)
+     module_path = g_build_path (G_SEARCHPATH_SEPARATOR_S,
+                               module_path_env, home_gtk_dir, default_dir, 
NULL);
++  else if (module_guix_gtk2_path_env)
++    module_path = g_build_path (G_SEARCHPATH_SEPARATOR_S,
++                              module_guix_gtk2_path_env, default_dir, NULL);
+   else if (module_path_env)
+     module_path = g_build_path (G_SEARCHPATH_SEPARATOR_S,
+                               module_path_env, default_dir, NULL);
-- 
2.5.0

>From b8120ae8e21e234ffd0eb9f5de1d7809a0860c45 Mon Sep 17 00:00:00 2001
From: Ricardo Wurmus <address@hidden>
Date: Thu, 3 Dec 2015 08:32:06 +0100
Subject: [PATCH 2/3] gnu: gtk+: Add patch to support GUIX_GTK3_PATH.

* gnu/packages/patches/gtk3-respect-GUIX_GTK3_PATH: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/gtk.scm (gtk+) [source]: Add patch.
[native-search-paths]: Add search path for GUIX_GTK3_PATH.
---
 gnu-system.am        | 1 +
 gnu/packages/gtk.scm | 9 +++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/gnu-system.am b/gnu-system.am
index 677ade5..580bd66 100644
--- a/gnu-system.am
+++ b/gnu-system.am
@@ -506,6 +506,7 @@ dist_patch_DATA =                                           
\
   gnu/packages/patches/guile-relocatable.patch                 \
   gnu/packages/patches/guile-rsvg-pkgconfig.patch              \
   gnu/packages/patches/gtk2-respect-GUIX_GTK2_PATH.patch       \
+  gnu/packages/patches/gtk3-respect-GUIX_GTK3_PATH.patch       \
   gnu/packages/patches/gtkglext-disable-disable-deprecated.patch \
   gnu/packages/patches/hop-bigloo-4.0b.patch                   \
   gnu/packages/patches/hop-linker-flags.patch                  \
diff --git a/gnu/packages/gtk.scm b/gnu/packages/gtk.scm
index 33feb2a..a4dd2d4 100644
--- a/gnu/packages/gtk.scm
+++ b/gnu/packages/gtk.scm
@@ -583,7 +583,8 @@ application suites.")
                                 name "-" version ".tar.xz"))
             (sha256
              (base32
-              "0lp1hn0qydxx03bianzzr0a4maqzsvylrkzr7c3p0050qihwbgjx"))))
+              "0lp1hn0qydxx03bianzzr0a4maqzsvylrkzr7c3p0050qihwbgjx"))
+            (patches (list (search-patch 
"gtk3-respect-GUIX_GTK3_PATH.patch")))))
    (propagated-inputs
     `(("at-spi2-atk" ,at-spi2-atk)
       ("atk" ,atk)
@@ -642,7 +643,11 @@ application suites.")
                  (loaders.cache (find-files librsvg "^loaders\\.cache$")))
             (wrap-program prog
               `("GDK_PIXBUF_MODULE_FILE" = ,loaders.cache))))
-        %standard-phases))))))
+        %standard-phases))))
+   (native-search-paths
+    (list (search-path-specification
+           (variable "GUIX_GTK3_PATH")
+           (files '("lib/gtk-3.0")))))))
 
 ;;;
 ;;; Guile bindings.
-- 
2.5.0

>From 2088ec24d2a69962310028d9cb686043fbde988d Mon Sep 17 00:00:00 2001
From: Ricardo Wurmus <address@hidden>
Date: Thu, 3 Dec 2015 08:49:30 +0100
Subject: [PATCH 3/3] gnu: ibus-libpinyin: Include more directories in
 GI_TYPELIB_PATH.

* gnu/packages/ibus.scm (ibus-libpinyin)[inputs]: Add "gdk-pixbuf",
  "at-spi2-atk", "atk", "pango".
[arguments]: Add the new inputs' girepository-1.0 directories to the
GI_TYPELIB_PATH.
---
 gnu/packages/ibus.scm | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/gnu/packages/ibus.scm b/gnu/packages/ibus.scm
index 770d7ff..bec7964 100644
--- a/gnu/packages/ibus.scm
+++ b/gnu/packages/ibus.scm
@@ -135,6 +135,16 @@ may also simplify input method development.")
                                    "/lib/girepository-1.0")))
                 `("GI_TYPELIB_PATH" ":" prefix
                   (,(string-append (assoc-ref inputs "ibus")
+                                   "/lib/girepository-1.0")
+                   ,(string-append (assoc-ref inputs "gtk+")
+                                   "/lib/girepository-1.0")
+                   ,(string-append (assoc-ref inputs "pango")
+                                   "/lib/girepository-1.0")
+                   ,(string-append (assoc-ref inputs "gdk-pixbuf")
+                                   "/lib/girepository-1.0")
+                   ,(string-append (assoc-ref inputs "at-spi2-atk")
+                                   "/lib/girepository-1.0")
+                   ,(string-append (assoc-ref inputs "atk")
                                    "/lib/girepository-1.0"))))
               #t))))))
    (inputs
@@ -144,7 +154,14 @@ may also simplify input method development.")
       ("sqlite" ,sqlite)
       ("python" ,python-2)
       ("pyxdg" ,python2-pyxdg)
-      ("gtk+" ,gtk+)))
+      ("gtk+" ,gtk+)
+
+      ;; These are propagated by gtk+, but we need them to add the
+      ;; girepository directories to the GI_TYPELIB_PATH.
+      ("gdk-pixbuf" ,gdk-pixbuf)
+      ("at-spi2-atk" ,at-spi2-atk)
+      ("atk" ,atk)
+      ("pango" ,pango)))
    (native-inputs
     `(("pkg-config" ,pkg-config)
       ("intltool" ,intltool)
-- 
2.5.0

~~ Ricardo