feat: budgeted console formatter (inspect builtin)

[edusperoni]

What

Replaces the console's no-DevTools formatting pipeline — which could hang the app on a single console.log — with internal/inspect.js, a budgeted util.inspect-lite built on primordials. Stacked on #415 (primordials), which is stacked on #411 (builtins).

The problem

console.log(obj) without a DevTools frontend serialized the whole object graph:

• JSON.stringify(obj, replacer, 2) with no depth or size limit — logging a store/component tree serialized everything reachable, then shipped megabytes through a stack-frame regex and NSLog.
• The replacer's seen array made cycle tracking O(n²) — quadratic interpreter work under jitless — and never popped on subtree exit, so shared acyclic references falsely printed [Circular].
• A separate hand-rolled array printer recursed with no depth limit and only caught an array containing itself — any indirect cycle was a stack overflow.
• JSON.stringify invokes getters and toJSON — a log line could execute arbitrary user code.
• console.dir had a third bespoke dump with the same issues.

The fix

inspect.js (function-body builtin, primordials-clean — it must work precisely when the app is broken):

• Budgets everywhere: depth 2 (dir uses 4), 100 entries per collection, 10k chars per string, 16KB hard cap per call with an explicit truncation marker. A pathological log is now bounded work by construction.
• Correct cycles: ancestor Set (enter/exit) — true cycles say [Circular], diamonds print normally, O(1) membership.
• Getters are never invoked ([Getter]/[Setter] tags). Two deliberate exceptions: a guarded error.stack read (V8 materializes stacks via a lazy accessor and every error path in the runtime already reads it), and custom toString overrides — NativeScript core's ViewBase/Observable convention (Button(42)-style short forms) is honored, matching the previous console: an own-or-inherited toString other than Object.prototype's is detected via descriptors (no invocation to detect), then invoked guarded and capped; broken overrides degrade to structural rendering.
• Tamper-immune: brands via captured Object.prototype.toString, Map/Set walked through captured iterator next (early-exit capable, unlike forEach), sizes via captured accessor getters. Verified by device tests that break Array.prototype.*, Object.keys, JSON.stringify etc. and log anyway.
• Native wrappers render as short hints ([UILabel], [class UIView], [Pointer]) via a binding.getNativeWrapperHint native callback instead of walking native-backed graphs.
• Type-aware: Map/Set with sizes, Date/RegExp/Error (with stack), [Function: name]/[class Name], TypedArrays/ArrayBuffers with lengths, null-prototype and constructor-name prefixes, sparse arrays, BigInt, symbols.
• Exposed as the internal __inspect global (testability + app-level escape hatch).

C++ side shrinks: console.log/dir/assert all route through one cached formatter; the array printer, the dir dump, and smart-stringify.js (+ its Helpers/Caches plumbing) are deleted. Top-level strings still print raw. If the formatter ever fails to initialize, logging degrades to ToDetailString instead of breaking.

Also extends primordials.js (Set methods, iterator next captures, accessor getters, brand/regexp helpers) and the ESLint captured-statics list.

Output changes to be aware of

Logs now look like Node's inspect output — { a: 1, b: [Circular] }, Map(3) { ... }, ... 150 more items, truncation markers — instead of pretty-printed JSON. console.dir keeps its dump markers but uses depth 4.

Testing

• 31 host-side functional assertions (Node harness over the same function bodies), including hostile stack getters and tampered prototypes.
• 9 new device specs (InspectTests.js): cycles vs diamonds, caps, getter non-invocation, native-wrapper hints, tampered-prototype formatting, and a regression test that console.log of a 5000-node cyclic graph completes in bounded time.
• Full suite: 922 tests, 0 failures (912 baseline + 10 new).

Also fixes a latent js2c bug this PR flushed out: builtin sources containing non-ASCII bytes (UTF-8 >= 0x80) failed to compile as const char array initializers; the generator now emits unsigned char.

Summary by CodeRabbit

• New Features

  • Improved console output with a safer, richer object inspector.
  • Added formatting for collections, dates, errors, functions, native objects, circular references, and typed data.
  • Added output limits and getter-safe formatting to prevent excessive or unexpected evaluation.

• Bug Fixes

  • Improved handling of custom formatting failures and complex object structures.
  • Console output is more resilient to modified built-in prototypes.

• Documentation

  • Documented the new inspection formatter and its safety protections.

• Tests

  • Added comprehensive coverage for inspection, truncation, cycles, getters, and native objects.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro Plus

Run ID: d1a1a216-1dbd-41d9-b6a1-7eb5a8029ba6

📥 Commits

Reviewing files that changed from the base of the PR and between d5c187c and 9720d56.

📒 Files selected for processing (15)

• NativeScript/runtime/BuiltinLoader.cpp
• NativeScript/runtime/Caches.h
• NativeScript/runtime/Console.cpp
• NativeScript/runtime/Console.h
• NativeScript/runtime/Helpers.h
• NativeScript/runtime/Helpers.mm
• NativeScript/runtime/js/README.md
• NativeScript/runtime/js/inspect.js
• NativeScript/runtime/js/primordials.js
• NativeScript/runtime/js/smart-stringify.js
• TestRunner/app/tests/InspectTests.js
• TestRunner/app/tests/index.js
• eslint.config.mjs
• tools/js2c-inputs.xcfilelist
• tools/js2c.mjs

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📝 Walkthrough

Walkthrough

The runtime replaces smart-stringify with a hardened inspect.js formatter. Console methods use the formatter for objects and functions. Primordials, native-wrapper hints, builtin packaging, documentation, and comprehensive tests were updated.

Changes

Inspect formatter integration

Layer / File(s)	Summary
Inspect formatter and primordial snapshot NativeScript/runtime/js/inspect.js, NativeScript/runtime/js/primordials.js, NativeScript/runtime/js/README.md, eslint.config.mjs	Adds bounded formatting for JavaScript values, native wrappers, cycles, collections, accessors, errors, and tampered built-ins. Captures the required primordial operations.
Console inspect integration NativeScript/runtime/Console.*, NativeScript/runtime/Helpers.*, NativeScript/runtime/Caches.h	Initializes and caches __inspect, routes console object formatting through it, adds native-wrapper hints, and removes the JSON stringification helpers.
Builtin packaging and runtime snapshot documentation tools/js2c-inputs.xcfilelist, tools/js2c.mjs, NativeScript/runtime/BuiltinLoader.cpp	Packages inspect.js, removes smart-stringify.js, supports unsigned generated source bytes, and updates the primordial snapshot comment.
Inspect behavior validation TestRunner/app/tests/InspectTests.js, TestRunner/app/tests/index.js	Adds inspect coverage for formatting, limits, getter safety, native objects, cycles, custom toString, performance, and tampered built-ins.

Estimated code review effort: 4 (Complex) | ~45 minutes

Sequence Diagram(s)

sequenceDiagram
  participant Console
  participant BuiltinLoader
  participant Inspect
  participant NativeWrapper
  Console->>BuiltinLoader: initialize inspect builtin
  BuiltinLoader->>Inspect: execute inspect.js
  Inspect-->>Console: cache formatter function
  Console->>Inspect: format object or function
  Inspect->>NativeWrapper: request wrapper hint when applicable
  NativeWrapper-->>Inspect: return native hint
  Inspect-->>Console: return bounded output

Loading

Possibly related PRs

• NativeScript/ios#411: Shares the builtin-loader and js2c infrastructure replaced by this inspect integration.
• NativeScript/ios#415: Shares the primordial snapshot infrastructure extended for the inspect formatter.

Suggested reviewers: nathanwalker

Poem

A rabbit inspects each leafy new line,
With primordials captured and output kept fine.
Cycles and getters stay safely in sight,
Native hints hop into the light.
Console now formats with a careful delight.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

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