feat(jsonnet): preserve hidden fields in rtkMemoize

[julienduchesne]

Summary

rtkMemoize cached values as a JSON string so it could share them across worker threads, which silently dropped hidden (::) fields — so it rejected any value containing one. Swap that JSON round-trip for a thread-portable OwnedVal snapshot that mirrors the jsonnet value model, so hidden fields survive memoization.

• Snapshot records per-field visibility and is rebuilt into a fresh Val (with :: restored) in each consuming thread; cache hits clone an Arc instead of reparsing JSON.
• Functions still can't be memoized, but instead of failing on the first one the error lists the path of every function found (e.g. spec.template.withName, <root>, items[0]).

Context

Val is Rc/Cc-based and bound to the evaluating thread, so the cross-worker cache must hold a Send/Sync value and rebuild per thread. JSON was the easy portable form but lossy. OwnedVal is an owned deep copy (scalars/arrays/objects + visibility) that stays portable without losing hidden data. Functions remain out of scope: a FuncVal captures a closure Context (free vars, self/super, std, imports) plus Rust builtins, none of which reduce to thread-independent data.

One behavioral note: snapshotting forces every field, including hidden ones, so a hidden field that errors now fails the memoize call even if it is never used.

Made with Cursor

[github-actions]

Benchmark Results

Benchmark	Test	vs tk	vs base
Diff	cluster_scoped	29.32x faster	equal
Diff	configmap_unchanged	29.51x faster	equal
Diff	deployment_nested_changes	27.99x faster	equal
Env List	Single Inline Directory (--json)	47.15x faster	equal
Env List	Single Inline File (--json)	46.99x faster	equal
Env List	All Environments (--json)	83.23x faster	equal
Eval	Single Static Environment	15.86x faster	equal
Eval	Inline Environment File	19.85x faster	equal
Eval	Eval Expression - Deeply Nested Path	16.04x faster	equal
Export (Full)	Single Static Environment	6.94x faster	equal
Export (Full)	Single Inline Environment	21.35x faster	equal
Export (Full)	All Environments	19.05x faster	equal
Export (Replace)	Single Static Environment	5.65x faster	equal
Export (Replace)	Single Inline Environment	21.24x faster	equal
Export (Replace)	All Environments	27.79x faster	equal
Helm Template	Full Export	1.4x faster	equal
Tool Importers Count	Single Lib Directory (Non-Recursive)	2.39x faster	equal
Tool Importers Count	Single Lib Directory (Recursive)	2.25x faster	equal
Tool Importers Count	Entire Lib Directory (Non-Recursive)	1.36x faster	equal
Tool Importers Count	Entire Lib Directory (Recursive)	1.11x faster	equal
Tool Importers	Global Lib File	3.17x faster	equal
Tool Importers	Single Env-Specific Lib File	1.68x faster	equal
Tool Importers	All Env-Specific Lib Files	5.18x faster	equal
Tool Importers	All Lib Files	5.21x faster	equal
Tool Importers	All Jsonnet Files	8.83x faster	equal
Tool Imports	Single Static Environment	3.56x faster	equal
Tool Imports	Single Inline Environment File	3.48x faster	equal
Validate Manifests	All Validations	-	equal
Validate Manifests	Manifest Tests Only	-	equal
Validate Manifests	Namespace Test Only	-	equal

Full results available in workflow artifacts.

Benchmark run on commit 5eed8a9bfed573af618c9692555151163c2d5e22