builder-manifest: Add argument to run compose with selected url policy

appstream-glib always composed with full urls. The URL policy got
unintentionallly switched to partial urls during libappstream port in
1.3.x.

Such a break in behaviour makes sense for unstable releases but we
cannot revert back to full urls in a stable release. Using full URLs
is desired for Flathub.

So add a cli arg to control the behaviour and default to partial url.
This may be flipped later in the next unstable release to default
to full urls again.

This is an alternative to #576

Author: bbhtt

doc/flatpak-builder.xml

@@ -589,6 +589,21 @@
                 </para></listitem>
             </varlistentry>
 
+            <varlistentry>
+                <term><option>--compose-url-policy=POLICY</option></term>
+
+                <listitem><para>
+                  Set the AppStream compose URL policy. Accepted values
+                  are <literal>partial</literal> and <literal>full</literal>.
+                  <literal>full</literal> requires AppStream version >= 0.16.3.
+                  Defaults to <literal>partial</literal> if unspecified.
+                  This policy only takes effect when used in conjunction
+                  with <option>--mirror-screenshots-url=URL</option>;
+                  otherwise the Appstream catalogue will preserve
+                  the source media URLs.
+                </para></listitem>
+            </varlistentry>
+
             <varlistentry>
                 <term><option>--add-tag=TAG</option></term>
 

src/builder-context.c

@@ -88,6 +88,8 @@ struct BuilderContext
   char           *opt_mirror_screenshots_url;
 
   BuilderSdkConfig *sdk_config;
+
+  BuilderAsUrlPolicy as_url_policy;
 };
 
 typedef struct
@@ -1241,6 +1243,19 @@ builder_context_create_state_dir (BuilderContext *self,
   return TRUE;
 }
 
+void
+builder_context_set_as_url_policy (BuilderContext     *self,
+                                   BuilderAsUrlPolicy  policy)
+{
+  self->as_url_policy = policy;
+}
+
+BuilderAsUrlPolicy
+builder_context_get_as_url_policy (BuilderContext *self)
+{
+  return self->as_url_policy;
+}
+
 BuilderContext *
 builder_context_new (GFile *run_dir,
                      GFile *app_dir,

src/builder-context.h

@@ -29,6 +29,11 @@
 
 G_BEGIN_DECLS
 
+typedef enum {
+  BUILDER_AS_URL_POLICY_PARTIAL = 0,
+  BUILDER_AS_URL_POLICY_FULL,
+} BuilderAsUrlPolicy;
+
 /* Same as SOUP_HTTP_URI_FLAGS, means all possible flags for http uris */
 
 #if GLIB_CHECK_VERSION (2, 68, 0)
@@ -185,6 +190,10 @@ BuilderSdkConfig * builder_context_get_sdk_config (BuilderContext *self);
 gboolean        builder_context_create_state_dir (BuilderContext *self,
                                                   GError        **error);
 
+void             builder_context_set_as_url_policy (BuilderContext      *self,
+                                                    BuilderAsUrlPolicy  policy);
+BuilderAsUrlPolicy builder_context_get_as_url_policy (BuilderContext   *self);
+
 G_DEFINE_AUTOPTR_CLEANUP_FUNC (BuilderContext, g_object_unref)
 
 G_END_DECLS

src/builder-main.c

@@ -89,6 +89,7 @@ static gboolean opt_log_session_bus;
 static gboolean opt_log_system_bus;
 static gboolean opt_yes;
 static gint64 opt_source_date_epoch = -1;
+static gchar *opt_as_url_policy = NULL;
 
 static GOptionEntry entries[] = {
   { "verbose", 'v', 0, G_OPTION_ARG_NONE, &opt_verbose, "Print debug information during command processing", NULL },
@@ -144,6 +145,7 @@ static GOptionEntry entries[] = {
   { "assumeyes", 'y', 0, G_OPTION_ARG_NONE, &opt_yes, N_("Automatically answer yes for all questions"), NULL },
   { "no-shallow-clone", 0, 0, G_OPTION_ARG_NONE, &opt_no_shallow_clone, "Don't use shallow clones when mirroring git repos", NULL },
   { "override-source-date-epoch", 0, 0, G_OPTION_ARG_INT64, &opt_source_date_epoch, "Use this timestamp to perform the build, instead of the last modification time of the manifest.", NULL },
+  { "compose-url-policy", 0, 0, G_OPTION_ARG_STRING, &opt_as_url_policy, "Set the AppStream compose URL policy to either 'partial' (default) or 'full'", "POLICY" },
   { NULL }
 };
 
@@ -608,6 +610,29 @@ main (int    argc,
   builder_context_set_opt_export_only (build_context, opt_export_only);
   builder_context_set_opt_mirror_screenshots_url (build_context, opt_mirror_screenshots_url);
 
+  if (opt_mirror_screenshots_url)
+    {
+      BuilderAsUrlPolicy policy = BUILDER_AS_URL_POLICY_PARTIAL;
+
+      if (g_strcmp0 (opt_as_url_policy, "full") == 0)
+        policy = BUILDER_AS_URL_POLICY_FULL;
+      else if (g_strcmp0 (opt_as_url_policy, "partial") == 0)
+        policy = BUILDER_AS_URL_POLICY_PARTIAL;
+      else if (opt_as_url_policy != NULL)
+        {
+          g_printerr ("Invalid value for --compose-url-policy: %s\n", opt_as_url_policy);
+          return 1;
+        }
+
+      if (policy == BUILDER_AS_URL_POLICY_FULL && !appstream_has_version (0, 16, 3))
+        {
+          g_printerr ("AppStream version >= 0.16.3 required for 'full' compose URL policy\n");
+          return 1;
+        }
+
+      builder_context_set_as_url_policy (build_context, policy);
+    }
+
   git_init_email ();
 
   if (!builder_context_create_state_dir (build_context, &error))

src/builder-manifest.c

@@ -2422,7 +2422,8 @@ cmpstringp (const void *p1, const void *p2)
 }
 
 static gboolean
-appstreamcli_compose (GError **error,
+appstreamcli_compose (GError             **error,
+                      BuilderAsUrlPolicy   as_url_policy,
                       ...)
 {
   g_autoptr(GPtrArray) args = NULL;
@@ -2433,7 +2434,10 @@ appstreamcli_compose (GError **error,
   g_ptr_array_add (args, g_strdup ("appstreamcli"));
   g_ptr_array_add (args, g_strdup ("compose"));
 
-  va_start (ap, error);
+  if (as_url_policy == BUILDER_AS_URL_POLICY_FULL)
+    g_ptr_array_add (args, g_strdup ("--no-partial-urls"));
+
+  va_start (ap, as_url_policy);
   while ((arg = va_arg (ap, const gchar *)))
     g_ptr_array_add (args, g_strdup (arg));
   g_ptr_array_add (args, NULL);
@@ -3066,6 +3070,7 @@ builder_manifest_cleanup (BuilderManifest *self,
                                                        flatpak_file_get_path_cached (icon_out));
           const char *opt_mirror_screenshots_url = builder_context_get_opt_mirror_screenshots_url (context);
           gboolean opt_export_only = builder_context_get_opt_export_only (context);
+          BuilderAsUrlPolicy as_url_policy = builder_context_get_as_url_policy (context);
 
           if (opt_mirror_screenshots_url && !opt_export_only)
             {
@@ -3077,6 +3082,7 @@ builder_manifest_cleanup (BuilderManifest *self,
               g_print ("Running appstreamcli compose\n");
               g_print ("Saving screenshots in %s\n", flatpak_file_get_path_cached (media_dir));
               if (!appstreamcli_compose (error,
+                                         as_url_policy,
                                          "--prefix=/",
                                          origin,
                                          arg_base_url,
@@ -3093,6 +3099,7 @@ builder_manifest_cleanup (BuilderManifest *self,
             {
               g_print ("Running appstreamcli compose\n");
               if (!appstreamcli_compose (error,
+                                         as_url_policy,
                                          "--prefix=/",
                                          origin,
                                          result_root_arg,