Detect broken XML paths and offer to fix on form load

src/core.js

@@ -473,6 +473,67 @@ fn.showConfirmBulkActionModal = function (confirmMessage, confirmActionFn) {
     $modal.modal('show');
 };
 
+fn.showPathCorrectionModal = function (corrections, formXML, options) {
+    var _this = this,
+        $modal;
+
+    function toAbsolutePath(path) {
+        return path.replace(/^#form/, '/data');
+    }
+
+    function applyCorrections() {
+        var fixedXML = formXML;
+        _.each(corrections, function (c) {
+            fixedXML = fixedXML.split(toAbsolutePath(c.wrongPath))
+                               .join(toAbsolutePath(c.correctPath));
+        });
+        _this.closeModal();
+        _this.data.core.parseWarnings = [];
+        _this.loadXML(fixedXML, options);
+        delete _this.data.core.parseWarnings;
+    }
+
+    function buildCorrectionList() {
+        var $list = $('<ul></ul>');
+        _.each(corrections, function (c) {
+            var wrong = toAbsolutePath(c.wrongPath),
+                correct = toAbsolutePath(c.correctPath),
+                leafName = wrong.split('/').pop();
+            $list.append(
+                $('<li></li>').append(
+                    document.createTextNode(gettext("Path ")),
+                    $('<code></code>').text(wrong),
+                    document.createTextNode(util.format(
+                        gettext(" was not found. A data node named " +
+                                "\"{name}\" exists at "),
+                        {name: leafName})),
+                    $('<code></code>').text(correct),
+                    document.createTextNode(".")
+                )
+            );
+        });
+        return $list;
+    }
+
+    $modal = this.generateNewModal(gettext("Broken Paths Detected"), [
+        {
+            title: gettext('Fix and Reload'),
+            cssClasses: "btn-primary",
+            action: applyCorrections
+        }
+    ], gettext("Ignore"));
+
+    var $body = $modal.find('.modal-body');
+    $body.append(
+        $('<p></p>').text(
+            gettext("The following paths in this form's XML do not match " +
+                    "any data nodes. Saving without fixing may result in data loss.")
+        ),
+        buildCorrectionList()
+    );
+    $modal.modal('show');
+};
+
 fn._init_extra_tools = function () {
     var _this = this,
         menuItems = this.getToolsMenuItems();
@@ -1411,6 +1472,10 @@ fn.loadXML = function (formXML, options) {
         _this._populateTree(selectedHashtag);
     }
 
+    if (form.pathCorrections && form.pathCorrections.length) {
+        _this.showPathCorrectionModal(form.pathCorrections, formXML, options);
+    }
+
     form.on('question-type-change', function (e) {
         _this.jstree("set_type", e.mug.ufid, e.qType);
 

src/parser.js

@@ -297,6 +297,18 @@ function parseControlElement(form, $cEl, parentMug) {
             path = getPathFromControlElement($cEl, form, parentMug);
         }
         mug = form.getMugByPath(path);
+        if (!mug && path) {
+            var match = findDataNodeByLeafName(form, path);
+            if (match) {
+                if (!form.pathCorrections) {
+                    form.pathCorrections = [];
+                }
+                form.pathCorrections.push({
+                    wrongPath: path,
+                    correctPath: match.absolutePath
+                });
+            }
+        }
     }
     mug = adapt(mug, form);
     var node = form.tree.getNodeFromMug(mug);
@@ -531,6 +543,27 @@ function parseBoolAttributeValue (attrString, undefined) {
     }
 }
 
+/**
+ * Search for an unclaimed data node whose nodeID matches the last
+ * segment of the given path. Used to recover from hand-edited XML
+ * where a control element's ref/nodeset has the wrong path.
+ *
+ * @param form - the form object
+ * @param path - the broken path (e.g., "/data/members_repeat")
+ * @returns - the matching DataBindOnly mug, or null
+ */
+function findDataNodeByLeafName(form, path) {
+    var leafName = path.replace(/^#form\//, '').split('/').pop();
+    var match = null;
+    _.each(form.mugMap, function (mug) {
+        if (mug.p.nodeID === leafName &&
+            mug.__className === 'DataBindOnly') {
+            match = mug;
+        }
+    });
+    return match;
+}
+
 /**
  * Figures out what the xpath is of a control element
  * by looking at the ref or nodeset attributes.