Forms: change phone dropdown flags handling

[CGastrell]

Part of FORMS-478

Proposed changes:

When WP emoji replacement scripts swaps our flag characters the interactivity API fails to bind with data-wp-text and the flags don't update.

Summary of the change:

1. PHP changes (class-contact-form-field.php):
   - Replaced data-wp-text with data-wp-watch="callbacks.updateSelectedFlag/updateOptionFlag"
   - Added ​ (zero-width space) placeholder to ensure a text node exists
   - Kept wp-exclude-emoji class as fallback for initial page parse
2. JS changes (view.js):
   - Added updateSelectedFlag and updateOptionFlag callbacks
   - These callbacks modify firstChild.data instead of textContent
   - Since wp-emoji's MutationObserver only watches childList (not characterData), modifying .data doesn't trigger emoji conversion

The key insight: wp-emoji's MutationObserver uses: .observe(document.body, { childList: true, subtree: true })

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

Does this pull request change what data or activity we track or use?

No

Testing instructions:

Before the fix:

• Emoji characters → converted to SVG tags by wp-emoji
• This broke the dropdown because data-wp-text would keep resetting to text, causing a conflict

After the fix:

• Emoji characters stay as emoji characters (no SVG conversion)
• The MutationObserver doesn't trigger because we modify .data instead of replacing textContent
• The dropdown works correctly

NOTE: in order to see the swap on local envs, you can use this on startup:

  add_action( 'wp_head', function() {
	// Inject script BEFORE the emoji detection (priority 7)
	// This sets fake "no support" values in sessionStorage
	?>
	<script>
	try {
	  sessionStorage.setItem('wpEmojiSettingsSupports', JSON.stringify({
		timestamp: Date.now(),
		supportTests: { flag: false, emoji: false }
	  }));
	} catch(e) {}
	</script>
	<?php
  }, 6 );
 
  // Force load the emoji scripts even if browser supports emojis
  add_action( 'wp_enqueue_scripts', function() {
	// Enqueue twemoji and wp-emoji scripts
	wp_enqueue_script(
	  'twemoji',
	  includes_url( 'js/twemoji.js' ),
	  array(),
	  false,
	  array( 'in_footer' => false )
	);
	wp_enqueue_script(
	  'wp-emoji',
	  includes_url( 'js/wp-emoji.js' ),
	  array( 'twemoji' ),
	  false,
	  array( 'in_footer' => false )
	);
  }, 100 );

[github-actions]

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• To test on WoA, go to the Plugins menu on a WoA dev site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin (Jetpack), and enable the fix/forms-phone-dropdown-flags-handling branch.
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[github-actions]

Thank you for your PR!

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• ✅ Include a description of your PR changes.
  
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• ✅ Add changelog entries to affected projects
  

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[Copilot]

Pull request overview

This PR fixes an issue where WordPress emoji replacement scripts would convert flag emoji characters to SVG images, breaking the phone field country selector dropdown in forms. The fix changes how flag updates are handled by using the Interactivity API's data-wp-watch with callbacks that directly modify text node data instead of textContent, thereby avoiding triggering wp-emoji's MutationObserver.

Key Changes:

• Replaced data-wp-text with data-wp-watch callbacks for flag rendering to bypass wp-emoji interference
• Added zero-width space (​) placeholder to ensure text nodes exist for manipulation
• Implemented two new callbacks (updateSelectedFlag and updateOptionFlag) that modify firstChild.data instead of textContent

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
projects/packages/forms/src/modules/field-phone/view.js	Added two new callbacks (updateSelectedFlag and updateOptionFlag) that update flag display by modifying text node data to avoid triggering wp-emoji's MutationObserver
projects/packages/forms/src/contact-form/class-contact-form-field.php	Updated phone field combobox HTML to use data-wp-watch with callbacks instead of data-wp-text, added wp-exclude-emoji class and zero-width space placeholder for flag elements
projects/packages/forms/changelog/fix-forms-phone-dropdown-flags-handling	Added changelog entry documenting the fix for phone combobox flag handling

[jp-launch-control]

Code Coverage Summary

Coverage changed in 1 file.

File	Coverage	Δ%	Δ Uncovered
projects/packages/forms/src/modules/field-phone/view.js	116/142 (81.69%)	1.54%	0 💚

Full summary · PHP report · JS report

_{Coverage check overridden by Coverage tests to be added later Use to ignore the Code coverage requirement check when tests will be added in a follow-up PR .}

[dhasilva]

LGTM, tests well