[perl-Glib-Object-Introspection] Avoid repeating setting up a library

[Torsten Schönfeld <tsch src gnome org>]

commit 863ea335c3ad4f576f3447c244354098fbab66d8
Author: Torsten Schönfeld <kaffeetisch gmx de>
Date:   Wed Jul 22 15:03:13 2015 +0200

    Avoid repeating setting up a library
    
    This can lead to issues, e.g., due to types being registered more than once
    with perl-Glib.  In particular, the lazy-loading mechanism of Glib::Object is
    not prepared to handle repeated type registrations.

 NEWS                             |    5 +++++
 gperl-i11n-vfunc-object.c        |    2 +-
 lib/Glib/Object/Introspection.pm |   13 ++++++++++++-
 3 files changed, 18 insertions(+), 2 deletions(-)
---
diff --git a/NEWS b/NEWS
index 6f31ee9..f80aa81 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,8 @@
+Overview of changes in Glib::Object::Introspection <next>
+========================================================
+
+* Avoid repeating setting up a library as this can lead to issues.
+
 Overview of changes in Glib::Object::Introspection 0.029
 ========================================================
 
diff --git a/gperl-i11n-vfunc-object.c b/gperl-i11n-vfunc-object.c
index 2f9be47..d1ab1c3 100644
--- a/gperl-i11n-vfunc-object.c
+++ b/gperl-i11n-vfunc-object.c
@@ -47,7 +47,7 @@ generic_class_init (GIObjectInfo *info, const gchar *target_package, gpointer cl
                         * struct member. */
                        HV * stash = gv_stashpv (target_package, 0);
                        GV * slot = gv_fetchmethod (stash, perl_method_name);
-                       if (!slot) {
+                       if (!slot || !GvCV (slot)) {
                                dwarn ("skipping vfunc %s.%s because it has no implementation\n",
                                      g_base_info_get_name (info), vfunc_name);
                                g_base_info_unref (vfunc_info);
diff --git a/lib/Glib/Object/Introspection.pm b/lib/Glib/Object/Introspection.pm
index a37b39e..09a27d3 100644
--- a/lib/Glib/Object/Introspection.pm
+++ b/lib/Glib/Object/Introspection.pm
@@ -28,6 +28,7 @@ require XSLoader;
 XSLoader::load(__PACKAGE__, $VERSION);
 
 my @OBJECT_PACKAGES_WITH_VFUNCS;
+my %SEEN;
 our %_FORBIDDEN_SUB_NAMES = map { $_ => 1 } qw/AUTOLOAD CLONE DESTROY BEGIN
                                                UNITCHECK CHECK INIT END/;
 our %_BASENAME_TO_PACKAGE;
@@ -68,6 +69,14 @@ sub setup {
   my $search_path = $params{search_path} || undef;
   my $name_corrections = $params{name_corrections} || {};
 
+  # Avoid repeating setting up a library as this can lead to issues, e.g., due
+  # to types being registered more than once with perl-Glib.  In particular,
+  # the lazy-loading mechanism of Glib::Object is not prepared to handle
+  # repeated type registrations.
+  if ($SEEN{$basename}{$version}{$package}++) {
+    return;
+  }
+
   $_BASENAME_TO_PACKAGE{$basename} = $package;
 
   my %shift_package_name_for = exists $params{class_static_methods}
@@ -177,9 +186,11 @@ sub setup {
   foreach my $packaged_signal (@use_generic_signal_marshaller_for) {
     __PACKAGE__->_use_generic_signal_marshaller_for (@$packaged_signal);
   }
+
+  return;
 }
 
-sub INIT {
+INIT {
   no strict qw(refs);
 
   # Hook up the implemented vfuncs first.