Use variations IDs in conversion events

[jjgrainger]

Changes proposed in this Pull Request:

Closes #3290

https://linear.app/a8c/issue/GOOWOO-503/purchase-event-sends-parent-product-id-instead-of-variation-id-for

Replace this with a good description of your changes & reasoning.

Detailed test instructions:

1. Add a variable product to the cart.
2. Go to the Cart page and view the page source and confirm that the gtag page view event uses the correct variation ID for the items ID.
3. Proceed to checkout and complete the order.
4. On the Order Received page, view the page source and confirm that the gtag purchase event uses the correct variation ID for the items ID.

Changelog entry

Fix - Conversion events use product variation ID in purchase events.

[codecov]

Codecov Report

❌ Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 67.1%. Comparing base (b8a7da7) to head (ad740c4).
⚠️ Report is 38 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/Google/GlobalSiteTag.php	50.0%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             develop   #3292     +/-   ##
===========================================
+ Coverage       66.8%   67.1%   +0.2%     
- Complexity      5152    5154      +2     
===========================================
  Files            886     512    -374     
  Lines          26682   20567   -6115     
  Branches        1551       0   -1551     
===========================================
- Hits           17836   13791   -4045     
+ Misses          8646    6776   -1870     
+ Partials         200       0    -200     

Flag	Coverage Δ
js-unit-tests	?
php-unit-tests	67.1% <50.0%> (ø)

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Files with missing lines	Coverage Δ
src/Google/GlobalSiteTag.php	35.9% <50.0%> (ø)

... and 374 files with indirect coverage changes

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Test Report: Verified ✅

Environment

• WordPress: 7.0-beta4-61919
• PHP: 8.3.23
• Server: nginx/1.26.1
• Database: mysqli (Server: 8.0.35 / Client: mysqlnd 8.3.23)
• Browser: Chrome 144.0.0.0
• OS: macOS
• Theme: Twenty Twenty-Five 1.4
• MU Plugins: None activated
• Plugins:
  • Force GLA Billing Status to Approved 1.0
  • Google for WooCommerce 3.5.3
  • WooCommerce 10.6.0-rc.1
  • WooCommerce Beta Tester 3.0.0

Test Result

The issue has been fixed. Previously, when an order contained a variable product, the "event - page_view" and "event - purchase" were sending the parent product ID instead of the variation product ID.

Example from our test:

• Parent Product ID: 206
• Variation Product ID: 266

Before the fix, both events were reporting 206. After the fix, the correct variation product ID (266) is now being used.

Befroe Fix:

event - page_view:

<script>
gtag("event", "page_view", {
send_to: "GLA",
ecomm_pagetype: "cart",
value: 300.000000,
items: [{
id: "gla_206",
price: 300.000000,
google_business_vertical: "retail",
name:"Sweater - Green",
quantity: 1,
}]});
</script>
 

event - purchase:

gtag("event", "purchase", {
			ecomm_pagetype: "purchase",
			send_to: "AW-17526712942/DeqACM6d9oUcEO7UsaVB",
			transaction_id: "277",
			currency: "USD",
			country: "US",
			value: 300.000000,
			new_customer: false,
			tax: 0.000000,
			shipping: 0.000000,
			delivery_postal_code: "282005",
			aw_feed_country: "US",
			aw_feed_language: "English",
			items: [{
				id: "gla_206",
				price: 300.000000,
				google_business_vertical: "retail",
				name: "Sweater - Green",
				quantity: 1,
				}]});

Recording.1735.mp4

---

After Fix:

event - page_view:

<script>
--
gtag("event", "page_view", {
send_to: "GLA",
ecomm_pagetype: "cart",
value: 600.000000,
items: [{
id: "gla_266",
price: 300.000000,
google_business_vertical: "retail",
name:"Sweater - Green",
quantity: 2,
}]});
</script>

event - purchase:

<script>
gtag("event", "purchase", {
			ecomm_pagetype: "purchase",
			send_to: "AW-17526712942/DeqACM6d9oUcEO7UsaVB",
			transaction_id: "278",
			currency: "USD",
			country: "US",
			value: 600.000000,
			new_customer: false,
			tax: 0.000000,
			shipping: 0.000000,
			delivery_postal_code: "282005",
			aw_feed_country: "US",
			aw_feed_language: "English",
			items: [{
				id: "gla_266",
				price: 300.000000,
				google_business_vertical: "retail",
				name: "Sweater - Green",
				quantity: 2,
				}]});
</script>

Recording.1734.mp4