Editor: Make sure that all edits after saving are considered "persistent".

[epiqueras]

Fixes #17852

Description

This PR fixes the issue discussed in #17852, by making sure that any change after a save is considered as persistent for undo level creation and change detection.

How has this been tested?

It was verified that #17852 was fixed and all the tests pass.

Types of Changes

Bug Fix: Fix an issue where editing the same block attribute after saving would not dirty the post again.

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.

[ellatrix]

Do you think it may be worth including the e2e test @mcsf provided?

[mcsf]

Do you think it may be worth including the e2e test @mcsf provided?

I'd like to, but when I tested last night I noticed that the test always passed if Puppeteer ran headless and with no SLOWMO factor. The test only worked (i.e. failing on master, passing here) when run more slowly.

It's always preferable to add a test along with these fixes, so — if you can timebox it — adding a properly working test would be good, otherwise just get the fix in. :)

For other readers: this is the test in question: #17852 (comment)

I then tried a different version, relying on waitForSelector so that it would work on fast test runners, but it still has issues. Sharing in case it's useful (and Ella has more experience writing these and might know what's up):

diff --git a/packages/e2e-tests/specs/change-detection.test.js b/packages/e2e-tests/specs/change-detection.test.js
index 0f384d7c3..9d0d7208b 100644
--- a/packages/e2e-tests/specs/change-detection.test.js
+++ b/packages/e2e-tests/specs/change-detection.test.js
@@ -6,6 +6,7 @@ import {
 	createNewPost,
 	pressKeyWithModifier,
 	ensureSidebarOpened,
+	openDocumentSettingsSidebar,
 	publishPost,
 } from '@wordpress/e2e-test-utils';
 
@@ -204,6 +205,50 @@ describe( 'Change detection', () => {
 		expect( hadInterceptedSave ).toBe( false );
 	} );
 
+	it( 'Should mark consecutive edits of a same attribute dirty if there was a save in between', async () => {
+		await clickBlockAppender();
+		await page.keyboard.type( 'Hello, World' );
+
+		// Save and wait for "Saved" to confirm save complete.
+		await Promise.all( [
+			page.waitForSelector( '.editor-post-saved-state.is-saved' ),
+			pressKeyWithModifier( 'primary', 'S' ),
+		] );
+
+		// Assert clean editor
+		expect( await page.$( '.editor-post-saved-state.is-saved' ) )
+			.toBeTruthy();
+
+		// Open the sidebar, switch to block settings
+		await openDocumentSettingsSidebar();
+		await page.click( '.edit-post-sidebar__panel-tab[data-label="Block"]' );
+
+		// Make sure our paragraph is selected
+		await page.click( '[data-type="core/paragraph"]' );
+
+		// In the block's inspector controls, increase the font size
+		await page.select( '.components-select-control__input', 'large' );
+		await page.click( '[data-type="core/paragraph"]' );
+
+		// Assert dirtiness
+		await page.waitForSelector( '.editor-post-save-draft' );
+		expect( await page.$( '.editor-post-saved-state.is-saved' ) ).toBeNull();
+
+		// Save and wait for "Saved" to confirm save complete.
+		await Promise.all( [
+			page.waitForSelector( '.editor-post-saved-state.is-saved' ),
+			pressKeyWithModifier( 'primary', 'S' ),
+		] );
+
+		// Increase the font size one more level
+		await page.select( '.components-select-control__input', 'larger' );
+		await page.click( '[data-type="core/paragraph"]' );
+
+		// Assert dirtiness
+		await page.waitForSelector( '.editor-post-save-draft' );
+		expect( await page.$( '.editor-post-saved-state.is-saved' ) ).toBeNull();
+	} );
+
 	it( 'Should prompt if save failed', async () => {
 		await page.type( '.editor-post-title__input', 'Hello World' );

[youknowriad]

I'm merging but please consider a test for this as a follow-up

[mcsf]

I'm merging but please consider a test for this as a follow-up

@epiqueras, mind filing an issue? ty!

[epiqueras]

#17914