Dry Run Preview

DryRun::generate() produces human-readable SQL statements with values interpolated inline. Use it to review what a merge would do before applying it to the database.

PHP

use Merql\Apply\DryRun;

$statements = DryRun::generate($result);

foreach ($statements as $sql) {
    echo "{$sql};\n";
}

Example output

Sql

INSERT INTO `posts` (`id`, `title`, `content`, `status`) VALUES ('42', 'New Post', 'Body text', 'draft');
UPDATE `posts` SET `title` = 'Updated Title', `status` = 'publish' WHERE `id` = '42';
DELETE FROM `posts` WHERE `id` = '99';

Value formatting

All values are wrapped in single quotes. Special characters are escaped for safe display:

Character	Escaped as
`\` (backslash)	`\\`
`'` (single quote)	`''`
`\0` (null byte)	`\0`
`\n` (newline)	`\n`
`\r` (carriage return)	`\r`

NULL values are rendered as the unquoted literal NULL:

Sql

UPDATE `posts` SET `subtitle` = NULL WHERE `id` = '42';

Parameters

DryRun::generate() accepts the same parameters as SqlGenerator::generate():

PHP

$statements = DryRun::generate(
    $result,
    base: $baseSnapshot,
    fkDependencies: ['comments' => ['posts']],
    driver: new SqliteDriver(),
);

Parameter	Type	Description
`$result`	`MergeResult`	The merge result to preview.
`$base`	`?Snapshot`	Base snapshot for identity columns. Falls back to `$result->baseSnapshot()`.
`$fkDependencies`	`array`	Foreign key dependency map for ordering.
`$driver`	`?Driver`	Database driver for identifier quoting.

Dry run vs SqlGenerator

DryRun wraps SqlGenerator. The difference:

SqlGenerator::generate() returns ['sql' => '...', 'params' => [...]] arrays intended for adapter prepared-statement execution.
DryRun::generate() returns flat strings with values inlined, intended for humans to read.

Do not execute dry run output as SQL. It is formatted for display, not for safe execution. For executing merges, use Applier or SqlGenerator directly with prepared statements.

Using with the facade

Through the facade, capture a merge result and preview it:

PHP

use Merql\Merql;
use Merql\Apply\DryRun;

$result = Merql::merge('base', 'ours', 'theirs');

$statements = DryRun::generate($result);

foreach ($statements as $sql) {
    echo "{$sql};\n";
}

Or from the CLI with the --dry-run flag:

Shell

./bin/merql merge base ours theirs --dry-run