compose: Print the goal

It's useful to see what's going to be installed before we do it.

src/rpmostree-compose-builtin-tree.c

@@ -365,6 +365,8 @@ install_packages_in_root (RpmOstreeTreeComposeContext  *self,
         g_print ("Previous commit found, but without rpmostree.inputhash metadata key\n");
     }
 
+  rpmostree_print_transaction (hifctx);
+
   /* --- Downloading packages --- */
   { g_auto(GLnxConsoleRef) console = { 0, };
     gs_unref_object HifState *hifstate = hif_state_new ();

src/rpmostree-treepkgdiff.c

@@ -199,3 +199,30 @@ rpmostree_print_treepkg_diff (OstreeSysroot    *sysroot,
   return ret;
 }
 
+
+void
+rpmostree_print_transaction (HifContext   *hifctx)
+{
+  guint i;
+  g_autoptr(GPtrArray) install;
+
+  install = hif_goal_get_packages (hif_context_get_goal (hifctx),
+                                   HIF_PACKAGE_INFO_INSTALL,
+                                   HIF_PACKAGE_INFO_REINSTALL,
+                                   HIF_PACKAGE_INFO_DOWNGRADE,
+                                   HIF_PACKAGE_INFO_UPDATE,
+                                   -1);
+
+  g_print ("Transaction: %u packages\n", install->len);
+  
+  if (install->len == 0)
+    g_print ("  (empty)\n");
+  else
+    {
+      for (i = 0; i < install->len; i++)
+        {
+          HyPackage pkg = install->pdata[i];
+          g_print ("  %s\n", hif_package_get_nevra (pkg));
+        }
+    }
+}

src/rpmostree-treepkgdiff.h

@@ -34,3 +34,6 @@ gboolean
 rpmostree_print_treepkg_diff (OstreeSysroot    *sysroot,
                               GCancellable     *cancellable,
                               GError          **error);
+
+void
+rpmostree_print_transaction (HifContext   *context);