Errors and migration to 2.0

Radiant 2.0 uses RadiantError instead of Error(Nil) for request accessors and reverse routing. This keeps failures explicit without exposing internal request or router structures.

Error variants

Variant	Meaning
`MissingHeader(name)`	The request does not contain the header
`InvalidUtf8Body`	The body is not valid UTF-8
`MissingPathParam(name)`	A path parameter was not captured or supplied
`InvalidIntParam(name, value)`	A captured path value is not an integer
`MissingQuery(name)`	The query parameter is absent
`InvalidIntQuery(name, value)`	The query value is not an integer
`InvalidFloatQuery(name, value)`	The query value is not a float
`InvalidBoolQuery(name, value)`	The query value is not `true`, `false`, `1`, or `0`
`MalformedQuery(value)`	The query string cannot be parsed
`MissingContext(name)`	No value was stored under the context key

Handling errors

case radiant.query_int(req, "page") {
  Ok(page) -> list_page(page)
  Error(radiant.MissingQuery(_)) -> radiant.json_error(400, "page is required")
  Error(radiant.InvalidIntQuery(_, _)) ->
    radiant.json_error(400, "page must be an integer")
  Error(radiant.MalformedQuery(_)) ->
    radiant.json_error(400, "malformed query string")
  Error(_) -> radiant.bad_request()
}

Use _ only for a deliberate fallback. Matching the named variants makes API responses more useful and prevents accidental conversion of malformed input into a generic 404.

Reverse routing

case radiant.path_for1(user_path, user_id, id) {
  Ok(path) -> radiant.redirect(path)
  Error(radiant.MissingPathParam(name)) ->
    radiant.internal_server_error_with("route is missing " <> name)
  Error(_) -> radiant.internal_server_error()
}

Path parameter values are percent-encoded. Wildcard values preserve / separators while encoding each individual segment.

Context keys

Use a namespace for every key:

pub const user_key = radiant.key_named("auth", "user")

Key(a) protects the value type at compile time, but key identity remains name-based at runtime. Namespacing avoids collisions between application and third-party middleware.

Migrating from 1.x

Change the package version constraint to >= 2.0.0 and < 3.0.0.
Replace Error(Nil) branches with Error(_), or match the relevant RadiantError variant.
Replace repeated names such as radiant.key("user") with radiant.key_named("module", "user").
Use radiant.wrap(middleware, handler) for middleware that should affect one route only.