# `email.partial_invalid`

An email template includes a partial that doesn't exist, can't be reached from it, or is given the wrong fields.

Area 16, [Built-in services](/docs/built-in-services.md); not declinable; the next step is usually the agent's.

## Why Jadpo refuses it

A partial is a piece several emails share, such as a button, declared as
a type with its own fields. A template includes it with
`{{ include name(field: value, ...) }}`, giving each field once by name,
so what the piece needs is checked where it is used. An include that
names a field the partial doesn't have, or a partial the template can't
reach, would send an email with a broken piece in it.

Jadpo won't guess which field a wrong name meant, so it refuses the
include when you check, rather than when the email is sent.

## What it looks like

The welcome email includes the shared button, which has a `label` and a
`url`.

shared/emails/button.jadpo:

```jadpo
/// A link set as a button.
type Button = EmailPartial {
    label: Text
    url: Url
}
```





domains/accounts/emails/welcome_email.html:

```jadpo
<p>Welcome, {{ name }}.</p>
{{ include button(label: name, link: notes_link) }}
```

```text
error: `button` has no field `link`
 --> domains/accounts/emails/welcome_email.html:2:32
  |
2 | {{ include button(label: name, link: notes_link) }}
  |                                ^^^^ not one of its fields
  reason: A partial is a `type Name = EmailPartial { ... }` in `shared/emails/` or the domain's own `emails/`, its `.html` and `.txt` beside it; a template includes it as `{{ include name(field: value, ...) }}`, giving each of its fields once by name, and its locale goes with it.
  next: Remove `link:` (agent)
  rule: email.partial_invalid
  help: https://jadpo.dev/docs/errors/email.partial_invalid

check failed: 1 error, 4 files
```

`(agent)` at the end of the `next:` line means your coding agent can make
the fix itself.

## How to fix it

**If the field has another name in the partial**, give it by that name.
`Button` calls the link `url`, so in
`domains/accounts/emails/welcome_email.html`:

```text
{{ include button(label: name, url: notes_link) }}
```









The welcome email's button now links to `notes_link`.

A partial in another domain's `emails/` can't be reached from this one.
Move it to `shared/emails/`, where every domain's emails may include it.

## Related

- [Partials: pieces several emails share](/docs/email.md#partials-pieces-several-emails-share)
- [Which partials a template reaches](/docs/mail-packages-partials-and-email-sent.md#which-partials-a-template-reaches)
- [What a template may not do](/docs/email.md#what-a-template-may-not-do)