Label text inserts extra space afterwards

[BryanCrotazGivEnergy]

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Description

{
    type: 'hems_desire_set_variable',
    tooltip: '',
    helpUrl: '',
    message0:
      '%1set %2',
    args0: [
      {
        type: 'field_label',
        name: 'thenLabel',
        value: '',
      },
      {
        type: 'field_dropdown',
        name: 'variable',
        options: [
          ['one', '1'],
          ['two', '2'],
          ['three', '3'],
        ],
      }    
    ],
  }

Should render "set [dropdown]"

Actually renders " set [dropdown]"

In code I'm setting the thenLabel to 'then' or '' based on the parent block. When I set it to 'then' it renders then set - note extra space.

Reproduction steps

Stack trace

Screenshots

No response

Browsers

Safari desktop

[gonfunko]

This is largely working as expected; when rendering, Blockly lays out all the text/labels/fields/inputs etc on the row, with spacing between them. The amount of spacing and rules for inserting it can be customized by using a custom renderer and overriding getInRowSpacing_(), but that's quite involved and likely not what you want to do here. Instead, I think if you changed message0 to be %1 %2, and then in your code toggle the thenLabel's text between "then set" and "set", you'd get the behavior you want; there would be two fields, with space between them, and the first would consist of the text while the latter would be the dropdown. At present, even when thenLabel is empty and not itself occupying space, Blockly still notes that a field is there and inserts padding between it and the "set" text; it's that padding that is the cause of the apparent space before "set" or between "then" and "set", so condensing down to just one label field that contains all of the text should sort it out. If that doesn't work for you feel free to reopen!

[BryanCrotaz]

Reopening.

The bug is that when a field has zero width only one padding should be inserted, not on both sides. If the field is the first one then no padding should be inserted.

In my case I'm applying this to multiple blocks and I don't know what the first word after thenLabel should be.