wp_dashboard_recent_comments function: avoid unnecessary SQL query

[kalessil]

Tune wp_dashboard_recent_comments performance:

• further reduce the number of count calls (related to the history of changes in this function)
• harden while-loop condition to avoid SQLs when the last query fetched less than what was aimed (next query fetches nothing)

Trac ticket: https://core.trac.wordpress.org/ticket/64506

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[github-actions]

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[Copilot]

Pull request overview

This PR optimizes the performance of the wp_dashboard_recent_comments function by reducing unnecessary function calls and avoiding SQL queries when no more results are available.

Changes:

• Replace repeated count($comments) calls with an incremented counter variable
• Add a condition to the while-loop to exit early when the last query returned fewer results than requested

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[Copilot]

The calculation of $fetch_count is incorrect. The get_comments() function uses number as the LIMIT parameter in SQL, which means it will fetch up to $comments_query['number'] items, not $comments_query['number'] - $comments_query['offset'].

For example, on the second iteration:

• $comments_query['offset'] = 25
• $comments_query['number'] = 50
• Current calculation: $fetch_count = 50 - 25 = 25
• Actual items fetched: up to 50

This causes the while-loop condition on line 1105 to incorrectly check if all requested items were returned. The correct calculation should be $fetch_count = $comments_query['number'].

Suggested change

	$fetch_count = $comments_query['number'] - $comments_query['offset'];
	$fetch_count = $comments_query['number'];