[erp5_web_renderjs_ui] Harden error handling in editable form

bt5/erp5_web_renderjs_ui/PathTemplateItem/web_page_module/rjs_gadget_erp5_pt_form_view_editable_js.js

@@ -158,6 +158,12 @@
                     error_text = 'Input data has errors';
                   } else if (error.target.status === 403) {
                     error_text = 'You do not have the permissions to edit the object';
+                  } else if (error.target.status === 0 && error.total === 0) {
+                    // backend cannot be reached and no data is being transfered 
+                    error_text = 'Document was not saved! Resubmit when you are online or the document accessible';
+                  } else {
+                    // display "unknown error" rather than destroying user's form data (throwing an error)
+                    error_text = 'Encountered an unknown error. Try to resubmit';
                   }
                   if (error_text !== undefined) {
                     return form_gadget.notifySubmitted()
@@ -168,16 +174,21 @@
                         return form_gadget.notifyChange(message + '.');
                       })
                       .push(function () {
+                        // when the server-side validation returns the error description
                         if (error.target.responseType === "blob") {
                           return jIO.util.readBlobAsText(error.target.response);
                         }
+                        // otherwise return (most-likely) textual response of the server
                         return {target: {result: error.target.response}};
                       })
                       .push(function (event) {
                         return form_gadget.displayFormulatorValidationError(JSON.parse(event.target.result));
-                      });
+                      })
+                      // most likely a JSON parse error because of invalid response which we will quietly ignore
+                      .fail(function () {});
                   }
                 }
+                // throwing an error is the last desperate option
                 throw error;
               });
           }

bt5/erp5_web_renderjs_ui/PathTemplateItem/web_page_module/rjs_gadget_erp5_pt_form_view_editable_js.xml

@@ -230,7 +230,7 @@
             </item>
             <item>
                 <key> <string>serial</string> </key>
-                <value> <string>958.31331.40640.10291</string> </value>
+                <value> <string>960.31544.14430.63812</string> </value>
             </item>
             <item>
                 <key> <string>state</string> </key>
@@ -248,7 +248,7 @@
                     </tuple>
                     <state>
                       <tuple>
-                        <float>1491385195.38</float>
+                        <float>1499089561.38</float>
                         <string>UTC</string>
                       </tuple>
                     </state>