# `HTTP.RequestError`
[🔗](https://github.com/gsmlg-dev/http_fetch/blob/v0.21.17/apps/http_fetch/lib/http/request_error.ex#L1)

Opt-in failure evidence returned with `error_mode: :structured`.

`reason` retains the original error. `phase: :connect` and
`request_started: false` prove that the TCP connection failed before it was
established, for direct TCP and OTP TLS routes using `redirect: :manual` or
`:error`. Automatic redirect chains always give conservative evidence.
`phase: :tls_setup` confirms a fatal handshake or certificate alert after
ServerHello and before HTTP transmission on a direct, unpooled HTTP/1 OTP
TLS route. It requires the ordinary handshake (no custom `handshake` or
`early_data` option) and tracking of both TLS processes before continuation.
Await cleanup separately before trying another validated pin.

All other failures report
`phase: :unknown` and `request_started: :unknown`, including earlier TLS failures,
pooled connections, cancellation, source/send/response errors, and deadlines
whose connection state cannot be confirmed. ExSSL failures are conservative.

`pre_send?/1` identifies the only evidence suitable for caller-managed
validated-address failover. Fetch never retries an attempt automatically.
The caller must preserve its original absolute deadline and cancellation
signal across attempts, and validate every address before providing a pin.
A stream stopped by a failed attempt must be replaced for another attempt.
This evidence does not replace the request cleanup completion barrier.

# `t`

```elixir
@type t() :: %HTTP.RequestError{
  phase: :connect | :tls_setup | :unknown,
  reason: term(),
  request_started: false | :unknown
}
```

# `pre_send?`

```elixir
@spec pre_send?(term()) :: boolean()
```

True only for a confirmed TCP or TLS setup failure before HTTP transmission.

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*Consult [api-reference.md](api-reference.md) for complete listing*