OPA v0.37.0 Release

[peteroneilljr]

This release contains a number of fixes and enhancements.

This is the first release that includes a binary and a docker image for
linux/arm64, opa_linux_arm64_static and openpolicyagent/opa:0.37.0-static.
Thanks to @ngraef for contributing the build changes necessary.

Strict Mode

There have been numerous possible checks in the compiler that fall into this category:

1. They would help avoid common mistakes; but
2. Introducing them would potentially break some uncommon, but legitimate use.

We've thus far refrained from introducing them. Now, a new "strict mode"
allows you to opt-in to these checks, and we encourage you to do so!

With OPA 1.0, they will become the new default behaviour.

For more details, see the docs on Compiler Strict Mode.

Delta Bundles

Delta bundles provide a more efficient way to make data changes by containing
patches to data instead of snapshots.
Using them together with HTTP Long Polling,
you can propagate small changes to bundles without waiting for polling delays.

See the documentation
for more details.

Tooling and Runtime

• Bundles bug fix: Roundtrip manifest before hashing to allow changing the manifest
  and still using signature verification of bundles (#4233),
  reported by @CristianJena

• The test runner now also supports custom builtins, when invoked through the Golang
  interface (authored by @MIA-Deltat1995)

• The compile package and the opa build command support a new output format: "plan".
  It represents a query plan, steps needed to take to evaluate a query (with policies).
  The plan format is a JSON encoding of the intermediate representation (IR) used for
  compiling queries and policies into Wasm.

  When calling opa build -t plan ..., the plan can be found in plan.json at the top-
  level directory of the resulting bundle.tar.gz.
  See the documentation for details..

• Compiler+Bundles: Metadata to be added to a bundle's manifest can now be provided via WithMetadata
  (#4289), authored by @marensws, reported by @johanneslarsson

• Plugins: failures in auth plugin resolution are now output, previously panicked, authored by @jcchavezs

• Plugins: Fix error when initializing empty decision logging or status plugin (#4291)

• Bundles: Persisted bundle activation failures are treated like failures with
  non-persisted bundles (#3840), reported by @dsoguet

• Server: http.send caching now works in system policy system.authz (#3946),
  reported by @amrap030.

• Runtime: Apply credentials masking on opa.runtime().config (#4159)

• opa test: removing deprecated code for --show-failure-line (-l), authored by @damienjburks

• opa eval: add description to all output formats

• opa inspect: unhide command for bundle inspection

Rego and Topdown

Built-in function enhancements and fixes:

• object.union_n: New built-in for creating the union of more than two objects (#4012),
  reported by @eliw00d
• graph.reachable_paths: New built-in to calculate the set of reachable paths in a graph (authored by @justinlindh-wf)
• indexof_n: New built-in function to get all the indexes of a specific substring (or character) from a string (authored by @shuheiktgw)
• indexof: Improved performance (authored by @shuheiktgw)
• object.get: Support nested key array for deeper lookups with default (authored by @charlieegan3)
• json.is_valid: Use Golang's json.Valid to avoid unnecessary allocations (authored by @kristiansvalland)

Strict-mode features:

• Add duplicate imports check (#2698) reported by @mikol
• Deprecate any() and all() built-in functions (#2437)
• Make input and data reserved keywords (#2600) reported by @jpeach
• Add unused local assignment check (#2514)

Miscellaneous fixes and enhancements:

• format: don't group iterable when one has defaulted location
• topdown: ability to retrieve input and plug bindings in the Event, authored by @istalker2
• print() built-in: fix bug when used with with modifier and a function call value (#4227)
• ast: don't error when future keyword import is redundant during parsing

Documentation

• A new "CLI" docs section describes the various
  OPA CLI commands and their arguments (#3915)
• Policy Testing: Add reference to rule indexing in the context of test code coverage
  (#4170), reported by @EKCs
• Management: Add hint that S3 regional endpoint should be used with bundles (authored by @danoliver1)
• Many broken links were fixed, thanks to @phelewski
• Fix rendering of details: add detail-tab for collapsable markdown (authored by @bugg123)

WebAssembly

• Add native support for json.is_valid built-in function
  (#4140), authored by @kristiansvalland
• Dependencies: bump wasmtime-go from 0.32.0 to 0.33.1

Miscellaneous

• Publish multi-arch image manifest lists including linux/arm64 (#2233),
  authored by @ngraef, reported by @povilasv
• logging: Remove logger GetFields function (#4114),
  authored by @viovanov
• Website: add versioned docs for latest version, so when 0.37.0 is released, both
  https://www.openpolicyagent.org/docs/v0.37.0/ and https://www.openpolicyagent.org/docs/latest
  contain docs, and 0.37.0 can already be used for stable links to versioned docs pages.
• Community: Initial draft of the community badges program
• make test: fix "too many open files" issue on Mac OS
• Various dependency bumps