Release v0.18.0

Features

The latest release of CEL introduces validators (#775) and optimizers (#804, #827) and migrates the core CEL internals off of the
protobuf expression and type representations (#789).

• String format validator [#775]
• Create a Function that Reverses a String [#796]
• Introduce pre-order / post-order visitor pattern [#813]
• Add Libraries() function to Env [#822]
• Static optimizer for constant folding [#804]
• Inlining optimizer [#827]
• FindStructTypeFields support for types.Provider [#814]

Breaking Changes

The following PR changes the API signature of the checker.AstNode method Expr to return an ast.Expr.

• Migrate the checker.Coster to the ast.Expr [#798]

Fixes

• Nil safety checks for cel.Ast [#784]
• Fix cost estimates to propagate result sizes [#787]
• Catch invalid literals created from expression factories [#810]
• Ensure stable ordering of overload candidates [#817]
• Clarify replace with/by empty string [#820]
• Fix functional exemptions for homogeneous literal checks [#832]
• Fix logical operator folding that only involve literals [#833]
• Upgrade go-genproto to latest [#831]

New Contributors

• @bboogler made their first contribution in #796

Full Changelog: v0.17.1...v0.18.0