Start from end of package lists when processing Requires

Prior to commit 6ecf318, the resolved list of required packages was
built in an appending way where each package on the command line or in
Requires would appear in the list in the order they appeared. With
6ecf318, that list building was changed to prepending, which had a
subtle change on the resolved order.

For example, suppose package a has "Requires: b c d". Previously, the
list would be built as a->b->c->d by appending each as they were
encountered. Now, the list is built by walking all the way down the
dependency chain for each package in a depth first manner and prepending
packages while unwinding. This would result in the package ilst being
a->d->c->b. This same effect happens with the command line packages
where previously requesting packages x and y would create a package list
of x->y and now produces a list of y->x.

While technically these should be the same since there are no
interdependencies, it's causes flags to be output in different order
than previously in pkg-config. This can be seen most readily in the
check-gtk test.

Instead, operate on the package lists backwards when building the
resolved package list.

check/check-gtk

@@ -15,8 +15,8 @@ PKG_CONFIG_LIBDIR=${srcdir}/gtk
 # -I/gtk/include -I/gtk/include/freetype2
 RESULT="-DGSEAL_ENABLE -pthread -I/gtk/include/gtk-3.0 \
 -I/gtk/include/pango-1.0 -I/gtk/include/atk-1.0 -I/gtk/include/cairo \
--I/gtk/include/gdk-pixbuf-2.0 -I/gtk/include -I/gtk/include/freetype2 \
--I/gtk/include/pixman-1 -I/gtk/include/glib-2.0 -I/gtk/lib/glib-2.0/include"
+-I/gtk/include/pixman-1 -I/gtk/include -I/gtk/include/gdk-pixbuf-2.0 \
+-I/gtk/include/glib-2.0 -I/gtk/lib/glib-2.0/include -I/gtk/include/freetype2"
 run_test --cflags gtk+-3.0
 run_test --cflags --static gtk+-3.0
 
@@ -26,9 +26,10 @@ run_test --cflags --static gtk+-3.0
 # -lpangocairo-1.0 -lgdk_pixbuf-2.0 -lcairo-gobject -lcairo -lpango-1.0 \
 # -lfreetype -lfontconfig -lgobject-2.0 -lgmodule-2.0 -lgthread-2.0 -lrt \
 # -lglib-2.0
-RESULT="-pthread -L/gtk/lib -lgtk-3 -lpangoft2-1.0 -lfontconfig -lfreetype \
--lgio-2.0 -latk-1.0 -lgdk-3 -lcairo-gobject -lgdk_pixbuf-2.0 -lpangocairo-1.0 \
--lcairo -lpango-1.0 -lgmodule-2.0 -lgobject-2.0 -lgthread-2.0 -lrt -lglib-2.0"
+RESULT="-pthread -L/gtk/lib -lgtk-3 -lgdk-3 -lpangocairo-1.0 -latk-1.0 \
+-lcairo-gobject -lcairo -lgdk_pixbuf-2.0 -lgio-2.0 -lpangoft2-1.0 \
+-lpango-1.0 -lgobject-2.0 -lgthread-2.0 -lgmodule-2.0 -lrt -lglib-2.0 \
+-lfreetype -lfontconfig"
 if [ "$list_indirect_deps" = no ]; then
     run_test --libs gtk+-3.0
 fi
@@ -46,11 +47,11 @@ fi
 # -lpixman-1 -lXrender -lX11 -lpthread -lxcb -lXau -lpng12 -lz -lm \
 # -lpango-1.0 -lfontconfig -lexpat -lfreetype -lgobject-2.0 -lffi \
 # -lgmodule-2.0 -ldl -lgthread-2.0 -lglib-2.0 -lrt
-RESULT="-pthread -L/gtk/lib -lgtk-3 -lpangoft2-1.0 -lgio-2.0 -lresolv \
--latk-1.0 -lgdk-3 -lcairo-gobject -lgdk_pixbuf-2.0 -lpangocairo-1.0 -lcairo \
--lXrender -lX11 -lpthread -lxcb -lXau -lpng12 -lz -lm -lfontconfig -lexpat \
--lfreetype -lpixman-1 -lpango-1.0 -lgmodule-2.0 -ldl -lgobject-2.0 -lffi \
--lgthread-2.0 -lglib-2.0 -lrt"
+RESULT="-pthread -L/gtk/lib -lgtk-3 -lgdk-3 -lpangocairo-1.0 -latk-1.0 \
+-lcairo-gobject -lcairo -lpixman-1 -lXrender -lX11 -lpthread -lxcb -lXau \
+-lgdk_pixbuf-2.0 -lpng12 -lm -lgio-2.0 -lz -lresolv -lpangoft2-1.0 \
+-lpango-1.0 -lgobject-2.0 -lffi -lgthread-2.0 -lgmodule-2.0 -ldl -lglib-2.0 \
+-lrt -lfontconfig -lexpat -lfreetype"
 if [ "$list_indirect_deps" = yes ]; then
     run_test --libs gtk+-3.0
 fi

check/check-non-l-flags

@@ -6,12 +6,8 @@ set -e
 
 RESULT="-I/non-l/include -I/non-l-required/include"
 run_test --cflags non-l-required non-l
-
-RESULT="-I/non-l/include -I/non-l-required/include"
 run_test --cflags --static non-l-required non-l
 
 RESULT="/non-l.a /non-l-required.a -pthread"
 run_test --libs non-l-required non-l
-
-RESULT="/non-l.a /non-l-required.a -pthread"
 run_test --libs --static non-l-required non-l

check/check-requires-private

@@ -5,11 +5,8 @@ set -e
 . ${srcdir}/common
 
 # expect cflags from requires-test and public-dep
-RESULT="-I/requires-test/include -I/public-dep/include -I/private-dep/include"
+RESULT="-I/requires-test/include -I/private-dep/include -I/public-dep/include"
 run_test --cflags requires-test
-
-# still expect those cflags for static linking case
-RESULT="-I/requires-test/include -I/public-dep/include -I/private-dep/include"
 run_test --static --cflags requires-test
 
 # expect libs for just requires-test and public-dep
@@ -19,7 +16,8 @@ if [ "$list_indirect_deps" = no ]; then
 fi
 
 # expect libs for requires-test, public-dep and private-dep in static case
-RESULT="-L/requires-test/lib -L/public-dep/lib -L/private-dep/lib -lrequires-test -lpublic-dep -lprivate-dep"
+RESULT="-L/requires-test/lib -L/private-dep/lib -L/public-dep/lib \
+-lrequires-test -lprivate-dep -lpublic-dep"
 if [ "$list_indirect_deps" = yes ]; then
     run_test --libs requires-test
 fi

pkg.c

@@ -633,7 +633,10 @@ recursive_fill_list (Package *pkg, GetListFunc func, GList **listp)
   /* record this package in the dependency chain */
   chain = g_list_prepend (chain, pkg);
 
-  for (tmp = (*func) (pkg); tmp != NULL; tmp = g_list_next (tmp))
+  /* Start from the end of the required package list to maintain order since
+   * the recursive list is built by prepending. */
+  for (tmp = g_list_last ((*func) (pkg)); tmp != NULL;
+       tmp = g_list_previous (tmp))
     recursive_fill_list (tmp->data, func, listp);
 
   *listp = g_list_prepend (*listp, pkg);
@@ -708,18 +711,14 @@ fill_list (GList *packages, GetListFunc func,
            GList **listp, gboolean in_path_order, gboolean include_private)
 {
   GList *tmp;
-  GList *expanded;
+  GList *expanded = NULL;
 
-  expanded = NULL;
-  tmp = packages;
-  while (tmp != NULL)
-    {
-      recursive_fill_list (tmp->data,
-			   include_private ? get_requires_private : get_requires,
-			   &expanded);
-
-      tmp = tmp->next;
-    }
+  /* Start from the end of the requested package list to maintain order since
+   * the recursive list is built by prepending. */
+  for (tmp = g_list_last (packages); tmp != NULL; tmp = g_list_previous (tmp))
+    recursive_fill_list (tmp->data,
+                         include_private ? get_requires_private : get_requires,
+                         &expanded);
 
   /* Remove duplicate packages from the recursive list. This should provide a
    * serialized package list where all interdependencies are resolved