# Changelog
## Unreleased
## [2.0.0] - 2026-03-31
### Added
- Add `LetMe.AllOf`, `LetMe.AnyOf`, `LetMe.Check`, `LetMe.Literal`, and
`LetMe.Not` structs and `t:LetMe.expression/0` type to represent policy
expressions.
- Add `error` option to `use LetMe.Policy`, `c:LetMe.Policy.authorize/4` to
switch between error structs without evaluation details, error structs with
evaluation details, and arbitrary custom error values.
- Support check matcher function as argument for `LetMe.filter_rules/2` and
`c:LetMe.Policy.list_rules/1`.
### Changed
- Evaluate authorization checks lazily.
- Change `c:LetMe.Policy.authorize/4` to always return an
`{:error, LetMe.UnauthorizedError.t()}` tuple when authorization checks
fail.
- Add `expression` field to `LetMe.UnauthorizedError.t()`, which contains the
policy expression and evaluation results until a decision was made.
- Replace `allow` and `deny` fields on `LetMe.Rule` struct with a single
`expression` field that contains a combined logical expression.
- Optimize the combined logical expression at compile time.
- Support check functions that return `:ok`, `:error`, `{:ok, term}`, or
`{:error, term}`. These return values can be read from the expression in the
`LetMe.UnauthorizedError` struct.
- Replace the `allow` and `deny` options in `LetMe.filter_rules/2` and
`c:LetMe.Policy.list_rules/1` with a single `check` option.
### Removed
- Remove `error_reason` and `error_message` options from `LetMe.Policy`.
### How to upgrade
Replace the `error_reason` and `error_message` options with the `error` option:
```diff
- use LetMe.Policy, error_reason: :forbidden, error_message: "Forbidden"
+ use LetMe.Policy, error: :forbidden
```
You can opt-in to detailed error structs by setting the value to `:detailed`
or simple error structs by setting the value to `:simple`.
```elixir
use LetMe.Policy, error: :detailed
```
If you do that, change all pattern matches on `{:error, :unauthorized}` or your
custom error reason and update your type specifications accordingly.
```diff
@spec update_article(Scope.t(), Article.t(), map) ::
- {:ok, Article.t()} | {:error, :unauthorized}
+ {:ok, Article.t()} | {:error, LetMe.Unauthorized.t()}
def update_article(scope, article, params)
with MyApp.Policy.authorize(:article_update, scope, article) do
# ...
end
end
case update_article(scope, article, params) do
{:ok, article} ->
# ...
- {:error, :unauthorized} ->
+ {:error, %LetMe.UnauthorizedError{}} ->
# ...
end
```
Replace the `allow` and `deny` option in `LetMe.filter_rules/2` and
`c:LetMe.Policy.list_rules/1` with the `check` option. The value is unchanged.
```diff
- MyApp.Policy.filter_rules(allow: {:role, :admin})
+ MyApp.Policy.filter_rules(check: {:role, :admin})
- MyApp.Policy.filter_rules(deny: :suspended)
+ MyApp.Policy.filter_rules(check: :suspended)
```
If you were working directly with the `allow` and `deny` fields of the
`LetMe.Rule` struct, update your code to work with the `expression` field and
`t:LetMe.expression/0` type instead.
## [1.2.5] - 2025-03-26
### Changed
- Improve documentation.
## [1.2.4] - 2024-04-22
### Fixed
- Nested lists within structs resulted in a `CaseClauseError` during redaction.
## [1.2.3] - 2023-11-11
### Changed
- Updated documentation.
## [1.2.2] - 2023-06-28
### Changed
- You can now override the exception message used by
`c:LetMe.Policy.authorize!/4` (e.g.
`use LetMe.Policy, error_message: "Not today, chap."`).
## [1.2.1] - 2023-06-28
### Changed
- Define `action` type when you `use LetMe.Policy`.
- Add type specifications for generated `authorize` functions.
## [1.2.0] - 2023-06-19
### Added
- Added an optional `opts` argument to the authorize functions, so that
additional options can be passed to pre-hooks.
- Updated `LetMe.filter_rules/2` to allow filtering by meta data.
### Changed
- Pre-hook options are now expected to be passed as a keyword list.
### Fixed
- Fix deprecation warning about `Logger.warn/2` in Elixir 1.15.
## [1.1.0] - 2023-05-08
### Added
- Added a `metadata` macro to add metadata to actions. The metadata can be read
from the `LetMe.Rule` struct.
## [1.0.3] - 2023-03-21
### Changed
- Update `ex_doc` and other dev dependencies.
## [1.0.2] - 2023-01-05
### Added
- Added a cheat sheet for rules and checks.
### Fixed
- Fixed a code example for rule introspection in the readme.
## [1.0.1] - 2022-11-06
### Changed
- Use `Keyword.pop/3` with default value instead of `Keyword.pop!/2`, so that
you can pass options to `LetMe.redact/3` without passing the `redact_value`
option.
## [1.0.0] - 2022-11-06
### Added
- Added `c:LetMe.Policy.filter_allowed_actions/3` and
`LetMe.filter_allowed_actions/4`.
- Added `c:LetMe.Policy.get_object_name/1`.
### Changed
- Renamed `c:LetMe.Policy.authorized?/3` to `c:LetMe.Policy.authorize?/3`,
because consistency is more important than grammar, maybe.
- The `c:LetMe.Schema.scope/2` callback was removed in favour of
`c:LetMe.Schema.scope/3`. The `__using__` macro defined default
implementations for both functions that returned the given query unchanged, in
case you only needed the `redact` callback of the behaviour. In practice, this
made it all too easy to call the 2-arity version when only the 3-arity
version was defined, and vice versa, which would lead the query to not be
scoped. So in order to reduce the room for error at the cost of a minor
inconvenience, you will now always need to implement the 3-arity function,
even if you don't need the third argument.
- Changed `c:LetMe.Schema.redacted_fields/2` to
`c:LetMe.Schema.redacted_fields/3` to allow passing additional options, and to
be consistent with `c:LetMe.Schema.scope/3`.
## [0.2.0] - 2022-07-12
### Changed
- Added support for nested field redactions, either by explicitly listing the
fields or by referencing a module that also implements `LetMe.Schema`.
### Fixed
- `reject_redacted_fields/3` called `redact/2` callback with the wrong argument
order.
## [0.1.0] - 2022-07-11
initial release
