schemaDiff()

Diff two JSON Schema documents.

Signature

JsonFast::schemaDiff(
    string $beforeSchema,
    string $afterSchema,
    ?int $output = OUTPUT_ARRAY
): mixed

Parameters

Name	Type	Default	Description
$beforeSchema	string	—	Original schema JSON
$afterSchema	string	—	Updated schema JSON
$output	?int	OUTPUT_ARRAY	Output mode

Returns

Structural difference between the two schemas — same general shape as diff() (added, removed, changed with JSON Pointer-style paths).

Use when reviewing API version bumps or generating changelog entries for contract changes.

Examples

Compare v1 and v2 API schemas:

$changes = JsonFast::schemaDiff(
    file_get_contents('schemas/v1.json'),
    file_get_contents('schemas/v2.json')
);

if (!empty($changes['removed'])) {
    notifyBreakingChange($changes['removed']);
}

CI check — schema must not drift unexpectedly:

$drift = JsonFast::schemaDiff($committedSchema, $generatedSchema);
assert(empty($drift['added']) && empty($drift['removed']) && empty($drift['changed']));

Related

• diff() — diff data documents
• getSchema() — infer schema from JSON