glib-compile-schema: Don't accept duplicate docs

This schema compiler was completely ignoring <summary> and
<description> tags. Unfortunately, there are modules out there
who merge translations for these back in, with xml:lang. And
this is giving dconf-editor a hard time. Since this is not
how translations of schemas are meant to be done, just
reject such schema files.

Also add tests exercising the new error handling.

https://bugzilla.gnome.org/show_bug.cgi?id=747209

gio/glib-compile-schemas.c

@@ -192,6 +192,9 @@ typedef struct
 
   gboolean      checked;
   GVariant     *serialised;
+
+  gboolean      summary_seen;
+  gboolean      description_seen;
 } KeyState;
 
 static KeyState *
@@ -208,6 +211,8 @@ key_state_new (const gchar *type_string,
   state->have_gettext_domain = gettext_domain != NULL;
   state->is_enum = is_enum;
   state->is_flags = is_flags;
+  state->summary_seen = FALSE;
+  state->description_seen = FALSE;
 
   if (strinfo)
     state->strinfo = g_string_new_len (strinfo->str, strinfo->len);
@@ -1374,9 +1379,27 @@ start_element (GMarkupParseContext  *context,
           return;
         }
 
-      else if (strcmp (element_name, "summary") == 0 ||
-               strcmp (element_name, "description") == 0)
+      else if (strcmp (element_name, "summary") == 0)
         {
+          if (state->key_state->summary_seen)
+            g_set_error (error, G_MARKUP_ERROR, G_MARKUP_ERROR_INVALID_CONTENT,
+                         _("Only one <%s> element allowed inside <%s>"),
+                         element_name, container);
+          state->key_state->summary_seen = TRUE;
+
+          if (NO_ATTRS ())
+            state->string = g_string_new (NULL);
+          return;
+        }
+
+      else if (strcmp (element_name, "description") == 0)
+        {
+          if (state->key_state->description_seen)
+            g_set_error (error, G_MARKUP_ERROR, G_MARKUP_ERROR_INVALID_CONTENT,
+                         _("Only one <%s> element allowed inside <%s>"),
+                         element_name, container);
+          state->key_state->description_seen = TRUE;
+
           if (NO_ATTRS ())
             state->string = g_string_new (NULL);
           return;

gio/tests/Makefile.am

@@ -130,6 +130,7 @@ schema_tests = \
 	default-in-aliases.gschema.xml			\
 	default-not-in-choices.gschema.xml		\
 	default-out-of-range.gschema.xml		\
+	description-xmllang.gschema.xml			\
 	empty-key.gschema.xml				\
 	enum-with-aliases.gschema.xml			\
 	enum-with-bad-default.gschema.xml		\
@@ -180,6 +181,7 @@ schema_tests = \
 	range-parse-error.gschema.xml			\
 	range-wrong-type.gschema.xml			\
 	range.gschema.xml				\
+	summary-xmllang.gschema.xml			\
 	wrong-category.gschema.xml			\
 	$(NULL)
 

gio/tests/gschema-compile.c

@@ -126,6 +126,8 @@ static const SchemaTest tests[] = {
   { "flags-more-than-one-bit",      NULL, "*flags values must have at most 1 bit set*"          },
   { "flags-with-enum-attr",         NULL, "*<enum id='flags'> not (yet) defined*"               },
   { "flags-with-enum-tag",          NULL, "*<flags id='flags'> not (yet) defined*"              },
+  { "summary-xmllang",              NULL, "*Only one <summary> element allowed*"                },
+  { "description-xmllang",          NULL, "*Only one <description> element allowed*"            },
   { "inherit-gettext-domain",       NULL, NULL                                                  },
   { "range-type-test",              NULL, NULL                                                  },
   { "cdata",                        NULL, NULL                                                  }

gio/tests/schema-tests/description-xmllang.gschema.xml

@@ -0,0 +1,13 @@
+<schemalist>
+  <schema path="/org/gnome/gnome-screenshot/" id="org.gnome.gnome-screenshot">
+    <key type="b" name="take-window-shot">
+      <default>false</default>
+      <summary>Bla</summary>
+      <description>Window-specific screenshot (deprecated)</description>
+      <description xml:lang="an">Captura especifica de finestra (obsoleto)</description>
+      <description xml:lang="ar">لقطة شاشة مختصّة بنافذة (مُبطل)</description>
+      <description xml:lang="as">উইন্ডোৰ ক্ষেত্ৰত নিৰ্দিষ্ট স্ক্ৰিনশ্বট (স্খলিত)</description>
+      <description xml:lang="ast">Captura específica de ventana (obsoleto)</description>
+    </key>
+  </schema>
+</schemalist>

gio/tests/schema-tests/summary-xmllang.gschema.xml

@@ -0,0 +1,13 @@
+<schemalist>
+  <schema path="/org/gnome/gnome-screenshot/" id="org.gnome.gnome-screenshot">
+    <key type="b" name="take-window-shot">
+      <default>false</default>
+      <summary>Window-specific screenshot (deprecated)</summary>
+      <summary xml:lang="an">Captura especifica de finestra (obsoleto)</summary>
+      <summary xml:lang="ar">لقطة شاشة مختصّة بنافذة (مُبطل)</summary>
+      <summary xml:lang="as">উইন্ডোৰ ক্ষেত্ৰত নিৰ্দিষ্ট স্ক্ৰিনশ্বট (স্খলিত)</summary>
+      <summary xml:lang="ast">Captura específica de ventana (obsoleto)</summary>
+      <description>Bla</description>
+    </key>
+  </schema>
+</schemalist>