Bug: updateBatch() silently ignores chained where() conditions, creating unsafe broad-update footgun

[KevinBlakeLopez]

PHP Version

8.4

CodeIgniter4 Version

4.7.0

CodeIgniter4 Installation Method

Composer (using codeigniter4/appstarter)

Which operating systems have you tested for this bug?

Linux

Which server did you use?

fpm-fcgi

Environment

production

Database

MySQL 8.0

What happened?

updateBatch() appears to allow normal Query Builder chaining, but prior where() conditions are not applied in the way a developer would reasonably expect.

This creates a dangerous footgun where code that appears constrained can perform a broader batch update than intended.

Example:

$db->table('form_fields')
    ->where('form_id', $formId)
    ->updateBatch($rows, 'id');

Steps to Reproduce

Given a table such as:

CREATE TABLE form_fields (
    id INT NOT NULL,
    form_id INT NOT NULL,
    label VARCHAR(255),
    PRIMARY KEY (id, form_id)
);

And rows:

INSERT INTO form_fields (id, form_id, label) VALUES
(1, 100, 'Form 100 Field 1'),
(1, 200, 'Form 200 Field 1');

Run:

$rows = [
    ['id' => 1, 'label' => 'Updated Label'],
];

$db->table('form_fields')
    ->where('form_id', 100)
    ->updateBatch($rows, 'id');

Expected Output

Either:

1. updateBatch() should apply the chained where() condition safely, or
2. preferably, updateBatch() should throw a DatabaseException when existing where() conditions are present, instructing developers to use the supported batch constraint API.

Expected safety behavior:

// Throw DatabaseException:
updateBatch() cannot be safely combined with existing Query Builder WHERE conditions. Use updateBatch($data, $constraints), onConstraint(), or include all required constraint fields in the batch data.

Anything else?

I am not proposing a broad SQL-generation redesign.

The minimal reliability fix would be to fail loudly when unsupported builder state is present before updateBatch() runs. Silent broad updates are a data-corruption-class failure mode.

Even if this chaining pattern is considered unsupported, the current behavior is dangerous because the fluent Query Builder API makes it look valid.