SQLite schema introspection implementation struggles with NULL default values

MySQL changed its handling of default values to allow blob, text or JSON in 8.0.13: https://dev.mysql.com/doc/refman/8.0/en/data-type-defaults.html

From #7...

`column1` INT DEFAULT NULL DEFAULT NULL, 
`column2` VARCHAR(20) DEFAULT NULL DEFAULT NULL, 

MySql seems to use the DEFAULT keyword twice, but no complains?

#10 another MySQL weirdness I guess, it apparently allows you to specify it any number of times and always takes the last specified value:

MariaDB [db]> create table table1 (column1 int default null default null default null default 0 default null default 0);
Query OK, 0 rows affected (0.012 sec)

MariaDB [db]> describe table1;
+---------+---------+------+-----+---------+-------+
| Field   | Type    | Null | Key | Default | Extra |
+---------+---------+------+-----+---------+-------+
| column1 | int(11) | YES  |     | 0       |       |
+---------+---------+------+-----+---------+-------+
1 row in set (0.001 sec)

+++ b/core/lib/Drupal/Core/Database/Driver/sqlite/Schema.php
@@ -505,10 +505,23 @@ protected function introspectSchema($table) {
-        if ($length) {
-          $schema['fields'][$row->name]['length'] = $length;

Why are we removing the column length info? Can we put it back.

We can add a length check for a column in SQLite.

CREATE TABLE IF NOT EXISTS "test"
(
    "id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
    "name" TEXT NOT NULL
    CHECK(
        typeof("name") = "text" AND
        length("name") <= 20
    )
);

The code is from https://stackoverflow.com/questions/12056571/limit-number-of-characters-....

All the code changes look good to me.
The bug has a fix and there is testing for the fix.
For me it is RTBC.

I bet it needs follow-up for #15 but RTBC++ the bug

+++ b/core/lib/Drupal/Core/Database/Driver/sqlite/Schema.php
@@ -505,11 +505,28 @@ protected function introspectSchema($table) {
+        }
+        elseif (is_numeric($row->dflt_value)) {
+          // Adding 0 to a string will cause PHP to convert it to a float or
+          // an integer depending on what the string is.
+          $schema['fields'][$row->name]['default'] = $row->dflt_value + 0;
+        }

This is tricky, is there something we can link to?

Or if not can we add a concrete example like:

'1' + 0 = 1

'1.0' + 0 = 1.0

Committed 8ce891e and pushed to 9.3.x. Thanks!