Patch modal handles invalid patches.

app/lib/NameLoader.coffee

@@ -18,6 +18,6 @@ class NameLoader extends CocoClass
   loadedNames: (newNames) =>
     _.extend namesCache, newNames
     
-  getName: (id) -> namesCache[id].name
+  getName: (id) -> namesCache[id]?.name or id
 
 module.exports = new NameLoader()

app/models/CocoModel.coffee

@@ -211,7 +211,9 @@ class CocoModel extends Backbone.Model
       jsondiffpatch.patch newAttributes, delta
     catch error
       console.error "Error applying delta", delta, "to attributes", newAttributes, error
+      return false
     @set newAttributes
+    return true
 
   getExpandedDelta: ->
     delta = @getDelta()

app/templates/editor/patch_modal.jade

@@ -7,7 +7,10 @@ block modal-header-content
 block modal-body-content
   .modal-body
     p= patch.get('commitMessage')
-    .changes-stub
+    if deltaWorked
+      .changes-stub
+    else
+      .alert.alert-danger Could not apply this delta to the current version.
 
 
 block modal-footer

app/views/editor/patch_modal.coffee

@@ -8,7 +8,7 @@ module.exports = class PatchModal extends ModalView
   template: template
   plain: true
   modalWidthPercent: 60
-  @DOC_SKIP_PATHS = ['_id','version', 'commitMessage', 'parent', 'created', 'slug', 'index', '__v', 'patches']
+  @DOC_SKIP_PATHS = ['_id','version', 'commitMessage', 'parent', 'created', 'slug', 'index', '__v', 'patches', 'creator']
 
   events:
     'click #withdraw-button': 'withdrawPatch'
@@ -24,29 +24,32 @@ module.exports = class PatchModal extends ModalView
       @originalSource = new @targetModel.constructor({_id:targetID})
       @supermodel.loadModel @originalSource, 'source_document'
       
+  onLoaded: ->
+    @headModel = null
+    if @targetModel.hasWriteAccess()
+      @headModel = @originalSource.clone(false)
+      @headModel.markToRevert true
+      @headModel.set(@targetModel.attributes)
+      @headModel.loaded = true
+
+    @pendingModel = @originalSource.clone(false)
+    @pendingModel.markToRevert true
+    @deltaWorked = @pendingModel.applyDelta(@patch.get('delta'))
+    @pendingModel.loaded = true
+    super()
+
   getRenderData: ->
     c = super()
     c.isPatchCreator = @patch.get('creator') is auth.me.id
     c.isPatchRecipient = @targetModel.hasWriteAccess()
     c.status = @patch.get 'status'
     c.patch = @patch
+    c.deltaWorked = @deltaWorked
     c
 
   afterRender: ->
-    return unless @supermodel.finished()
-    headModel = null
-    if @targetModel.hasWriteAccess()
-      headModel = @originalSource.clone(false)
-      headModel.markToRevert true
-      headModel.set(@targetModel.attributes)
-      headModel.loaded = true
-
-    pendingModel = @originalSource.clone(false)
-    pendingModel.markToRevert true
-    pendingModel.applyDelta(@patch.get('delta'))
-    pendingModel.loaded = true
-
-    @deltaView = new DeltaView({model:pendingModel, headModel:headModel, skipPaths: PatchModal.DOC_SKIP_PATHS})
+    return super() unless @supermodel.finished() and @deltaWorked
+    @deltaView = new DeltaView({model:@pendingModel, headModel:@headModel, skipPaths: PatchModal.DOC_SKIP_PATHS})
     changeEl = @$el.find('.changes-stub')
     @insertSubView(@deltaView, changeEl)
     super()