During domToWorkspace() child block with FieldDropdown is in workspace's topblock

I updated blockly in a project from 1.20190419.0 to “npm”: “blockly”: “2.20190722.1”

In order to restore a view, I use Blockly.Xml.domToWorkspace(this.contentData.content, this.workspace);

In our project we only have one top/root block (with childs) by design. Some child blocks have FieldDropdown, which are filled with a function like

	new Blockly.FieldDropdown(function createSelectedDataTableField_func() {
		let selectedTables = [];
		...
		return selectedTables;

with FieldDropdown values depending on what is set in the root block.

With Blockly 1.20190419.0 => OK

But with Blockly 2.20190722.1 after domToWorkspace, I faced the following. Traces in console like:

Cannot set the dropdown’s value to an unavailable option. Block type: dataset_field_table_column, Field name: FIELD_TABLE, Value: mapchartbycust

In the createSelectedDataTableField_func() call, the child block’s getRootBlock() is itself O_o And the workspace has two+ top blocks, the good one and the child(s). So If I call getRootBlock() to do a let xyz = rootBlock.getFieldValue('SELECTED_TABLE'); call it won’t work anymore.

I had to (bad) hack our code with

	if(rootBlock.type == 'dataset_field_table_column') {
	  rootBlock = rootBlock.workspace.getTopBlocks()[0];
	}

to select the “good” root block.

Later, I get the Blockly.Events.BLOCK_CREATE event, and the child(s) block(s) are (back) to root block childs => OK

Expected behavior

Like before

Desktop (please complete the following information):

• OS: Windows 10
• Browser Chrome
• Version 76.0.3809.100

[rachel-fenichel]

Thanks for the detailed repro information!

This sounds like a change in the initialization order for fields that broke your blocks. It’s not a surprise that blocks are on the workspace when created, and are then attached to the expected parent, but your initialization function must be being called early than it used to be.

@BeksOmega any ideas before I dig in?

[ArfyFR]

@samelhusseini , @rachel-fenichel should I open a new issue ?