Block library: Extract deprecated field to their own files

[gziolo]

Description

Part of aligning block library to Block Registration API RFC #13693.

It's all about moving deprecated fields to their own file to follow the proposal drafted in RFC.

Updated blocks:

• Gallery
• Image

Removed block deprecations

• Heading - see Block library: Extract deprecated field to their own files #15057 (comment)
• List - see Block library: Extract deprecated field to their own files #15057 (comment)

How has this been tested?

npm test
npm run test-e2e

Manually tested whether all blocks load as before.

[ellatrix]

It's a bit hard to review this without any tests for deprecated blocks. Would it be possible to add some simple tests to see if deprecated block structures are converted correctly?

[gziolo]

It's a bit hard to review this without any tests for deprecated blocks. Would it be possible to add some simple tests to see if deprecated block structures are converted correctly?

Good idea. I will add something based on the existing fixtures. I think Columns and Paragraph block have some coverage already:

• https://github.com/WordPress/gutenberg/blob/master/packages/e2e-tests/fixtures/blocks/core__paragraph__deprecated.html
• https://github.com/WordPress/gutenberg/blob/master/packages/e2e-tests/fixtures/blocks/core__columns__deprecated.html

[gziolo]

@ellatrix, I opened #15268 with tests covering all possible deprecations. Let's merge it first and then rebase this one.

[gziolo]

Blocked by #15268.

[gziolo]

Based on my question #15268 (comment):

I tried to add tests for List and Heading blocks but it looks like deprecated versions left for those blocks don't work anymore. It looks like #7349 was added temporary and wasn't planned to be supported for long. Does it mean we can safely remove them?

I can confirm that we those deprecations won't work anymore for List and Heading blocks and can be safely removed. The related logic that handles source: property was removed in https://github.com/WordPress/gutenberg/pull/8276/files#diff-7dae7b3890cf27659680c926b6992e31L108.