Open Policy Agent - v0.57.0

This release contains an updated Rego syntax to allow general references in rule heads, and a mix of new features and bugfixes.

Support for General References in Rule Heads

In OPA 0.56.0, we introduced support for general references in rule heads as an experimental feature.
It has now graduated to a fully supported feature, and is no longer experimental.

A general reference is a reference with variables at arbitrary locations.
In Rego, partial rules are used for generating sets and objects.
In previous versions of OPA, variables were only allowed in the very last position in the rule's reference.
Now, Rego has been expanded to allow rules to be declared with general references in their head, with variables at arbitrary locations.
This allows for generating nested dynamic object structures:

package example

import future.keywords

# Converting a flat list of users to a mapping by "role" and then "id".
users_by_role[role][id] := user if {
    some user in data.users
    id := user.id
    role := user.role
}

# Explicit "admin" key override to the above mapping.
users_by_role.admin[id] := user if {
    some user in data.admins
    id := user.id
}

# Leaf entries can be multi-value.
users_by_country[country] contains user.id if {
    some user in data.users
    country := user.country
}

See the documentation for more information.

Authored by @johanfylling.

Runtime, Tooling, SDK

• ast/runtime: Extend type checking for authz policies (#6213) authored by @ashutosh-narkar
• server: Add test case for bundle update - query API handler scenario (#4792) authored by @ashutosh-narkar

Topdown and Rego

• ast: Accept short-form else bodies (#6157) authored by @Ronnie-personal
• plugins: Surface AWS authentication error details (#6232) authored by @ashutosh-narkar
• topdown: Builtin function to parse uuid with google/uuid library (#6173) authored by @Od1nB

Miscellaneous

• ast: Add location to single entry rule head ref (#6199) authored by @Ronnie-personal
• ast: Add option to marshal location text (#6213) authored by @charlieegan3
• types: New algorithm for (Any).Union + new benchmarks (#6228) authored by @philipaconrad
• Updates to documentation and website authored by @charlieegan3
• docs: Link to expressing or post (#6236) (authored by @charlieegan3)
• docs: Use links on support page (#6249) (authored by @charlieegan3)
• Dependency updates; notably:
• golang from 1.21 to 1.21.1
• golang.org/x/net from 0.14.0 to 0.15.0
• google.golang.org/grpc from 1.57.0 to 1.58.2
• github.com/containerd/containerd from 1.7.4 to 1.7.6

Breaking Changes

GO SDK: the ast.JSONOptions struct has changed location to ast.json.Options.