Description:
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I am running into an issue with PHP 7.3.2 where calling mysqli_fetch_field hangs the script.  The same script in PHP 7.2.15 runs successfully.

It only occurs when calling store_result() with MYSQLI_STORE_RESULT_COPY_DATA

It could be related to bug #68548 that I submitted a few years ago, but something changed in PHP 7.3.2 that causes the call to hang completely now.

For the below test script, I'm using SQL:

DROP TABLE IF EXISTS a;
CREATE TABLE a (b int);
INSERT INTO a VALUES (1),(2),(3),(4),(5),(6),(7),(8),(9);


Test script:
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<?php
$mysqli = new mysqli('localhost', 'test', 'test', 'test');

$mysqli->real_query("SELECT * FROM a");

$result = $mysqli->store_result(MYSQLI_STORE_RESULT_COPY_DATA);

$field = $result->fetch_field();


Expected result:
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Script runs and instantly exits.


Actual result:
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In PHP 7.3.2 with MYSQLI_STORE_RESULT_COPY_DATA, the script hangs.

In PHP 7.2.15 with MYSQLI_STORE_RESULT_COPY_DATA, the script runs and instantly exits.

In PHP 7.3.2 without MYSQLI_STORE_RESULT_COPY_DATA, the script runs and instantly exits.

In PHP 7.2.15 without MYSQLI_STORE_RESULT_COPY_DATA, the script runs and instantly exits.