initialValue block setting doesn't work

[wesleybl]

Describe the bug
initialValue block setting doesn't work.

To Reproduce
Steps to reproduce the behavior:

1. Create a block with the initialValue setting. For example:

function initialValue({ id, value, formData, intl }) {
  return {
    ...formData.blocks[id],
    myField: 'test',
  };
}
const applyConfig = (config) => {
  config.blocks.blocksConfig.myBlock = {
    id: 'myBlock',
    initialValue: initialValue,
    ...
  };
  return config;
};

2. Add the block to a page
3. The myField field is not filled with the value 'test'.

Expected behavior
The myField field should be filled with the value 'test'.

Software (please complete the following information):

Volto 18.0.0-alpha.27
Plone 6.0.10
plone.restapi 9.5.0

Additional context
The configuration does not work because the block id that is passed to the _applyBlockInitialValue function is the id of the previous block, and not the id of the newly created block. See:

volto/packages/volto/src/helpers/Blocks/Blocks.js

Line 307 in 0edcd80

id,

The id passed there should be newBlockId and not id.

Even making this fix, one thing that still happens is that when the previous one is a block of text, the setting is not applied. The insertBlock method is not called in this situation. I wouldn't know where to call _applyBlockInitialValue in this situation. I know that the changeBlock method is called in this situation. But I don't know if it would be the right place, since it is called several times.

[wesleybl]

@tiberiuichim any tips on how to make this work if the previous block is a text block?

[wesleybl]

In fact, insertBlock is not called if the previous block is an empty text block. If the text block is not empty, insertBlock is called.
The difference between adding a block after any block and after a empty text block is here:

volto/packages/volto/src/components/manage/Blocks/Block/EditBlockWrapper.jsx

Lines 109 to 115 in 24d9484

	onInsertBlock={(id, value) => {
	if (blockHasValue(data)) {
	onSelectBlock(onInsertBlock(id, value));
	} else {
	onChangeBlock(id, value);
	}
	}}

When the previous block is an empty text block, if returns false and then onChangeBlock is called. In other situations onSelectBlock is called.

Maybe _applyBlockInitialValue has to be called before calling onChangeBlock.

[tiberiuichim]

The id passed there should be newBlockId and not id.

You are correct here