Fixed implementation of path alias settings.

Now report an error if path is already aliased to another location.

examples/demo/site/themes/bootstrap/assets/css/style.css

@@ -76,3 +76,9 @@ ul.horizontal li {
   border-width: 2px 1px 0;
   padding: 2px 7px 1px;
 }
+
+#message li.error {
+  background-color: #f99;
+  border: solid 1px red;
+  padding: 5px 2px 5px 2px;
+}

examples/demo/site/themes/bootstrap/assets/scss/style.scss

@@ -81,3 +81,8 @@ ul.horizontal {
 		}
 	}
 }
+#message li.error {
+	background-color: #f99;
+	border: solid 1px red;
+	padding: 5px 2px 5px 2px;
+}

modules/node/cms_node_api.e

@@ -182,7 +182,7 @@ feature -- URL
 		require
 			a_node.has_id
 		do
-			create Result.make (a_node.title, cms_api.path_alias (node_path (a_node)))
+			create Result.make (a_node.title, cms_api.location_alias (node_path (a_node)))
 		end
 
 	node_path (a_node: CMS_NODE): STRING

modules/node/handler/cms_node_type_webform_manager.e

@@ -102,7 +102,7 @@ feature -- Forms ...
 				if attached a_node.link as lnk then
 					l_uri := lnk.location
 				else
-					l_uri := percent_encoder.percent_decoded_string (response.api.path_alias (response.node_api.node_path (a_node)))
+					l_uri := percent_encoder.percent_decoded_string (response.api.location_alias (response.node_api.node_path (a_node)))
 				end
 				ti.set_text_value (l_uri)
 				ti.set_description ("Optionally specify an alternative URL path by which this content can be accessed. For example, type 'about' when writing an about page. Use a relative path or the URL alias won't work.")
@@ -122,6 +122,9 @@ feature -- Forms ...
 								else
 										-- TODO: implement full path alias validation
 								end
+								if attached a_response.api.location_alias (f_path_alias) as l_aliased_location then
+									fd.report_invalid_field ("path_alias", "Path is already aliazed to location %"" + l_aliased_location + "%" !")
+								end
 							end
 						end(?, response)
 					)

src/service/cms_api.e

@@ -305,6 +305,18 @@ feature -- Path aliases
 			storage.unset_path_alias (a_source, a_alias)
 		end
 
+	location_alias (a_source: READABLE_STRING_8): READABLE_STRING_8
+			-- Location alias associated with `a_source' or the source itself.
+		do
+			Result := a_source
+			if attached storage.path_alias (Result) as l_path then
+				Result := l_path
+				if Result.starts_with ("/") then
+					Result := Result.substring (2, Result.count)
+				end
+			end
+		end
+
 	path_alias (a_source: READABLE_STRING_8): READABLE_STRING_8
 			-- Path alias associated with `a_source' or the source itself.
 		do