Module diff 

Available on crate features diff and openapi only.

Schema diffing — compare two JSON Schemas to find breaking changes.

Useful for API versioning: detect when a schema change will break existing consumers.

Requires the diff feature. It works on plain serde_json::Value JSON Schemas (e.g. from json_schema() with the openapi feature, or any other source).

Direction: the classification assumes request / input schemas — a change is breaking when the new schema rejects input the old one accepted (stricter), non-breaking when it only accepts more. For response schemas read it the other way round.

Nullable wrappers (anyOf/oneOf of [X, {"type": "null"}], as emitted by .optional() / .nullable()) are unwrapped and X is compared; gaining null is non-breaking, losing it is breaking. anyOf / oneOf / allOf branches are compared position by position, $ref targets by name.

Example

use serde_json::json;
use vld::diff::{diff_schemas, ChangeKind};

let old = json!({
    "type": "object",
    "required": ["name", "email"],
    "properties": {
        "name": { "type": "string" },
        "email": { "type": "string", "format": "email" }
    }
});

let new = json!({
    "type": "object",
    "required": ["name", "email", "age"],
    "properties": {
        "name": { "type": "string" },
        "email": { "type": "string" },
        "age": { "type": "integer" }
    }
});

let changes = diff_schemas(&old, &new);
assert!(changes.has_breaking());

Structs

SchemaChange

A single schema change.

SchemaDiff

Result of diffing two schemas.

Enums

ChangeKind

Severity of a schema change.

Functions

diff_schemas

Compare two JSON Schemas and return a list of changes.