log workspace update errors

Workspace update errors can be partially recovered from. This allows
the gui to "successfully" load on projects that pass vm validation and
loading but throw an error in scratch-blocks. Logging the error instead
of throwing it allows the gui and vm to finish updating for the
workspace change. This allows the VM to behave normally even if the
scratch-blocks workspace rendering is incomplete.

src/containers/blocks.jsx

@@ -8,6 +8,7 @@ import VMScratchBlocks from '../lib/blocks';
 import VM from 'scratch-vm';
 
 import analytics from '../lib/analytics';
+import log from '../lib/log.js';
 import Prompt from './prompt.jsx';
 import ConnectionModal from './connection-modal.jsx';
 import BlocksComponent from '../components/blocks/blocks.jsx';
@@ -300,7 +301,21 @@ class Blocks extends React.Component {
         // Remove and reattach the workspace listener (but allow flyout events)
         this.workspace.removeChangeListener(this.props.vm.blockListener);
         const dom = this.ScratchBlocks.Xml.textToDom(data.xml);
-        this.ScratchBlocks.Xml.clearWorkspaceAndLoadFromXml(dom, this.workspace);
+        try {
+            this.ScratchBlocks.Xml.clearWorkspaceAndLoadFromXml(dom, this.workspace);
+        } catch (error) {
+            // The workspace is likely incomplete. What did update should be
+            // functional.
+            //
+            // Instead of throwing the error, by logging it and continuing as
+            // normal lets the other workspace update processes complete in the
+            // gui and vm, which lets the vm run even if the workspace is
+            // incomplete. Throwing the error would keep things like setting the
+            // correct editing target from happening which can interfere with
+            // some blocks and processes in the vm.
+            error.message = `Workspace Update Error: ${error.message}`;
+            log.error(error);
+        }
         this.workspace.addChangeListener(this.props.vm.blockListener);
 
         if (this.props.vm.editingTarget && this.state.workspaceMetrics[this.props.vm.editingTarget.id]) {