Update dependency Jint to 4.17.0

[renovate]

ℹ️ Note

This PR body was truncated due to platform limits.

This PR contains the following updates:

Package	Change	Age	Confidence
Jint	4.16.0 → 4.17.0

---

Release Notes

sebastienros/jint (Jint)

v4.17.0

Jint 4.17.0 is a release from the 4.x branch. It backports correctness and conformance fixes from main (four of them for scripts that could end the host process), linear string building, and two new opt-in APIs for hosts. That is why it is a minor release rather than a patch. Nothing in it changes an existing API or an existing default, so it is a drop-in update from 4.16.4.

Highlights

A pooled engine can let go of a finished request's objects. Hosts that reuse one engine across many evaluations (CaptureGlobalSnapshot once, RestoreGlobalSnapshot between runs) keep the interpreter's warmed caches, and that is the point of reusing it. But a warmed call site remembers the last function it called, and a warmed member read remembers the last object it read from. In a pooled web host, that can be a delegate built from a finished request's services, which then stay alive until the same script runs again. The new Engine.Advanced.DiscardInterpreterCaches() drops those caches, so the objects can be collected. The engine, its intrinsics and its global object stay as they are. The next run of each script rebuilds its cache, which costs roughly what a first run on a new engine costs, minus building the engine. A good place to call it is when an engine has been idle for a while, rather than after every use (#​4229, from #​4227).

A host can carry its own state across await. Jint now runs ECMAScript's HostMakeJobCallback and HostCallJobCallback steps for every promise reaction, every thenable job and the FinalizationRegistry cleanup callback. A host can take part through the new Options.Host.JobCallbacks, which accepts a JobCallbackHooks with Capture, Enter and Exit callbacks. That lets each branch of a Promise.all fan-out keep its own host context, such as a logging scope or ambient request data, through every await (#​4231, from #​4230; issue #​4200). The default is no hooks, in which case each promise registration costs one null check and nothing a script can observe changes.

Four more ways for a script to end the host process are closed.

• ShadowRealm. A failure crossing a ShadowRealm boundary threw its TypeError copy from inside the catch that was handling the original failure. That added a nested exception dispatch at every hop, and no stack check could see it. Even with the stack-overflow guard on, a long chain of wrapped functions ended the process on the way back out, and a three-line script with a name getter needed no chain at all. Building that copy also ran script (toString, getters, proxy traps); it no longer does. A failed importValue now reports the import failure instead of an unrelated error (#​4220, from #​4176 and #​4183).
• instanceof and eval. instanceof now checks the native stack before calling a custom Symbol.hasInstance method, and eval checks it before parsing. A self-referencing Symbol.hasInstance, or var s = 'eval(s)'; eval(s), now raises a RangeError the script can catch instead of ending the process. On the MaxExecutionStackCount path, eval also stopped hopping to a new thread at each overflow without ever throwing. instanceof over a bound function now consults every bound link's own Symbol.hasInstance, as the specification requires (#​4221, from #​4172, #​4184 and #​4187).
• These checks follow 4.x's existing rule. Like every other stack check on 4.x, they are active only when Options.Constraints.StackOverflowGuard is on, so turn it on for any script you do not fully trust.

Building a string with s = s + x is linear. A + whose result reaches 512 characters now produces a deferred string instead of copying both sides. Building with s = s + x, s = x + s and s = s + a + b therefore becomes linear, as s += x already was. Short concatenations take a separate path and pay nothing for this. The deferred string is safe to read from several engines that share one Prepared<Script>, and it is charged to LimitMemory when it is built, so a memory limit still bounds it. Binding an already-bound function also no longer copies its whole "bound …" name at every level (#​4160, from #​3386, #​3571, #​4130, #​4164 and #​4173).

Array.prototype.concat spreads host arrays and lists. Since 4.14, CLR arrays and lists reach script as live views by default. concat added such a view as a single element instead of spreading its items, so a.concat(b) returned the two wrappers. It now spreads anything script sees as an array (#​4219, from #​4216; issue #​4201).

TypedArray.prototype.with survives a shrinking coercion. When converting the index or the value made a resizable buffer shorter, with copied past its new end and let a CLR ArgumentException escape. It now copies only what the buffer still holds (#​4218, from #​4157).

Verification

Every backport was verified failing-first: its tests were run against the unfixed 4.x tree on .NET 10 and .NET Framework 4.7.2, then with the change. The release candidate was measured against 4.16.4 on SunSpider and Dromaeo in six paired rounds, alternating which build ran first in each round. The four Dromaeo ObjectRegExp rows ran 12–15% faster and SunSpider's 3d-raytrace 2.3% faster. No row regressed by 1% or more; the two rows whose interval did not include zero (one Dromaeo Cube variant, +0.70%, and SunSpider's controlflow-recursive, +0.88%) are within this machine's run-to-run noise.

What's Changed

• Backport culture-independent overload-scoring fixture to 4.x by @​PrzemyslawKlys in #​4215
• Backport #​4216 to 4.x: make Array.prototype.concat spread host arrays and lists by @​lahma in #​4219
• Backport #​4176, #​4183 to 4.x: keep a ShadowRealm failure copy from killing the host or running script by @​lahma in #​4220
• Backport #​3386, #​3571, #​4130, #​4164 and #​4173 to 4.x: linear string building, safe across engines and charged to LimitMemory by @​lahma in #​4160
• Backport #​4172, #​4184, #​4187 to 4.x: stop instanceof and eval recursions from killing the host by @​lahma in #​4221
• Backport #​4157 to 4.x: Fix TypedArray.prototype.with after a shrinking coercion by @​lahma in #​4218
• Backport #​4227 to 4.x: Let a reused engine discard the host objects its warmed caches hold by @​lahma in #​4229
• Backport #​4230 to 4.x: Let a host carry its own state across await through HostMakeJobCallback by @​lahma in #​4231

Full Changelog: sebastienros/jint@v4.16.4...v4.17.0

v4.16.4

Jint 4.16.4 is a maintenance release from the 4.x branch. It backports correctness and conformance fixes from main — three of them for scripts that could end the host process — together with a few measured performance improvements, and nothing in it changes an existing API or an existing default. If you are on 4.16.3 it is a drop-in update — every public signature is the one 4.16.0 shipped, on all five target frameworks, and the per-framework snapshots in Jint.Tests.PublicInterface/Verify/ are unchanged. main remains 5.0.0 development; what is coming there is recorded as it lands in docs/v5-migration.md.

Highlights

A number reads as the same double on every target framework. Before .NET 9, the runtime's ulong-to-double and string-to-double conversions double-round, and Jint inherited that: a whole-number literal in [2⁶³, 2⁶⁴) held a different double on .NET Framework and .NET 8 than on .NET 10 (#​3531); parseFloat, Number and JSON.parse mis-rounded past their integer window on .NET Framework, and JSON.parse('1e999') threw a CLR OverflowException out of the engine instead of answering Infinity (#​3535); a fraction or exponent literal could land one ULP away on .NET Framework (#​3538); and parseInt and wide radix literals now hold the Number nearest the integer they denote on every framework, with a legacy octal no longer re-read as decimal (#​3537). The string-to-number lanes and trim now accept exactly the white space the parser does — U+0085 NEL no longer counts, and a byte-order mark no longer breaks Number or BigInt (#​3542) — and an exponent scan no longer clamps at 10⁶ (#​3593). All six arrive together as #​4120, because they share one parser. This changes numeric results — to the correct ones. The literal and string-to-number fixes change answers on .NET Framework only; parseInt, radix literals, the white-space set and the exponent clamp change them on every framework.

BigInt('+12') is 12n. The decimal spelling of a StringIntegerLiteral may carry a sign, so a leading + is accepted there and only there; BigInt('+0x10') stays a SyntaxError (#​4121).

A split keeps its segments when a constraint runs script. String.prototype.split filled a thread-shared scratch list and checks constraints every 10,000 segments; a host Constraint that ran script on the same thread could clear the list an outer split was still filling, which then returned only the segments added afterwards (#​4122).

An overload is not a fit for a number it cannot hold. Overload scoring gated float, short, byte and their kin on the value fitting, but not int and long — so 3000000000 was a perfect match for an int parameter, the wider overload beside it was never tried, and the host saw a CLR OverflowException rather than a catchable JavaScript error (#​4123).

Intl's locale lookup stops paying for a culture it does not need. BestAvailableLocale resolved a CultureInfo on every truncation step even though the available-locale set answers almost every lookup by itself; it now resolves one only when the set cannot answer (#​4124).

Intl.Locale canonicalizes every Unicode extension keyword value. UTS #​35 canonicalizes a keyword's value in two halves — the CLDR bcp47 aliases, and the removal of a value of "true" — and Jint did only the first, while Intl.Locale's own tag scanner did neither. So en-u-ca-true kept its true, en-u-kb-yes kept its yes although the data aliases it to true, and en-u-ks-primary was never aliased to level1 on the tag path. The firstDayOfWeek option was read as a Number before a String and cast to int, so 0.5 resolved to "sun" where the spec rejects it, and NaN and Infinity became whatever the framework's cast made of them — which differed between .NET and .NET Framework (#​4156).

An object used as a rotating cache stops compacting forever. A property removed from an object's store leaves a tombstone, so that a re-added key keeps its creation order. Removing the newest entry already reclaimed its slot; removing the oldest — the shape of a bounded cache, a fresh name in and the oldest out — left a hole each time, and the table compacted every capacity − live additions although the live set never grew: a 16-key rotation settled on a capacity of 64 and compacted 209 times per 10,000 steps. The entries are now a window that may wrap around the array, so a removal at either end retires its slot; the same rotation never resizes and settles on 32 (#​4155).

Chains that script can make as long as it likes no longer end the process. Resolving a property through a prototype chain recursed one native frame per link, so a 20,000-deep { __proto__: x } chain overflowed the native stack on a read, a write, an in or a with lookup and ended the process — nothing thrown, nothing for a catch to see (#​4170, from #​4078; issue #​4076, reported by @​Tielem). [[Get]], [[Set]] and [[HasProperty]] now walk the chain in a loop, so an ordinary or shaped-host-prototype chain of any depth simply answers. Function.prototype.bind chains had the same shape in IsConstructor and in the realm lookup new and Reflect.construct perform, and those are loops now too (#​4169, from #​4165); on .NET Framework the JIT happened to turn both into tail calls, so the process death was a .NET 8 / .NET 10 one.

Two chains cannot be flattened, because each link has work of its own to do on the way back out: a proxy forwarding to a proxy, and host object wrappers stacked on each other (#​4170, from #​4125; issue #​4087). Those are probed instead, and raise a catchable RangeError — when Options.Constraints.StackOverflowGuard is on. On 4.x that guard remains opt-in (it becomes the default only in 5.0), so an engine left at its defaults still ends the process on a deep enough proxy chain. If you run script you do not control, turn the guard on; with it on, a 20,000-link proxy chain used as an array's constructor or as Reflect.construct's newTarget now raises RangeError where it used to end the process.

% stops allocating for numbers. The remainder operator now takes the unboxed numeric lane multiplication and division already used, so sum += i % 97 reads a numeric counter without materialising a JsNumber per step — on the benchmark's arithmetic loop, allocation per run drops from 2.87 MB to under 1 KB (#​4167, from #​4154).

Intl.Locale.prototype.getWeekInfo reads the region the specification picks. It read CLDR's week data for the tag's literal region subtag only, so a tag without one got the world's week and the -u-rg- and -u-sd- keywords were ignored. It now follows RegionPreference: a -u-rg- override, then the region subtag, then a -u-sd- subdivision's region, then the region Add Likely Subtags supplies, then 001. This changes answers — new Intl.Locale('en').getWeekInfo().firstDay is now 7 (en is likely en-US, where the week starts on Sunday) rather than 1, and en-US-u-rg-gbzzzz answers 1 rather than 7 — in each case to what the specification and every browser give (#​4168, from #​4163).

Verification

Every backport was verified failing-first: its tests were run against the unfixed 4.x tree on .NET 10 and .NET Framework 4.7.2, then with the change.

PR	tests	unfixed .NET Framework	unfixed .NET 10	after
#​4120 (#​3531)	whole-number literals, 22	15 fail	0 fail	all pass
#​4120 (#​3535)	string to number, 41; JsonTests, 170	22 + 8 fail	0 fail	all pass
#​4120 (#​3538)	fraction / exponent literals, 50	16 fail	0 fail	all pass
#​4120 (#​3537)	parseInt, 124; radix literals, 21	96 + 12 fail	96 + 12 fail	all pass
#​4120 (#​3542)	white space, 35	22 fail	22 fail	all pass
#​4120 (#​3593)	exponent clamp, 5	1 fail	1 fail	all pass
#​4121	StringToBigInt, 46	16 fail	16 fail	all pass
#​4122	constraint re-entrancy, 2	1 fail	1 fail	all pass
#​4123	numeric overload range, 20	10 fail	10 fail	all pass
#​4124	culture lookup count, 8	1 fail	1 fail	all pass
#​4155	creation order across rotation, 53	6 fail	6 fail	all pass
#​4156	Intl.Locale canonicalization, 81	30 fail	30 fail	all pass
#​4167	modulo lane, 8 (semantics only)	0 fail	0 fail	all pass — the lane is proven by allocation: 2,873,104 B → 784 B per run
#​4168	getWeekInfo region preference, 26; test262 getWeekInfo region files, 8	13 + 8 fail	13 + 8 fail	all pass
#​4169	bound and proxy chain walks, 3	pass (JIT tail-calls)	3 end the process	all pass
#​4170	deep prototype (9), shaped-prototype (8), trapless proxy (3) and wrapper (2) chain rows, plus the PlainObject census	12 end the process, 1 fails, census fails	19 end the process, census fails	all pass

Release diagnostics on the tagged commit's tree (a19802dda703), in Release: Jint.Tests 7,655 (net10.0) and 7,570 (net472); Jint.Tests.PublicInterface 1,903 and 1,895; Jint.Tests.CommonScripts 28 and 28; Jint.Tests.SourceGenerators 52; the host-contract verification leg (JINT_HOST_CONTRACT_VERIFICATION=1) 7,655 / 7,570 and 1,907 / 1,899 — zero failures anywhere, and the PublicInterface surface snapshots unchanged. test262: 102,509 passed, 0 failed, 175 skipped — the 4.x control plus the eight getWeekInfo cases #​4168 un-excluded. CI passed the same tree on Linux x64, Linux ARM64, Windows, macOS and the host-contract leg.

The release was gated before the tag on a paired comparison against 4.16.3 — DefaultJob, alternating order, on an idle machine with nothing else running and Defender's real-time scanning off — measuring the exact tree that was tagged. A three-round screen over 98 rows (SunSpider, Dromaeo, and the benchmarks for each backported lane) was followed by an eight-round re-measurement of every row that agreed in sign across the screen.

lane	row	change against 4.16.3
prototype-chain walk (#​4170)	HostPrototypeShape.AbsentNameMissOverChain	−17.7% / −18.1%
	PrototypeChainRead.AbsentNameRead	−15.6%
	HostPrototypeShape.DeepHitOverChain	−7.2% / −8.6%
% without allocation (#​4167)	ModuloMaterialization.Arithmetic	−21.0%
numeric parsing (#​4120)	NumberParse.ParseFloatLoop	−14.2%
	NumberParse.NumberCoerce	−3.6%
rotating key sets (#​4155)	PropertyDeleteChurn.RotateOldest[64]	−2.7%
JSON	Json.Parse / Json.Stringify	no change, or faster
SunSpider + Dromaeo	50 rows	no row regressed past run-to-run noise; the largest moves were faster (up to −5.1%)

One small, confirmed cost: PropertyDeleteChurn.RotateBehindPinnedKey — rotating keys through an object whose oldest key is never deleted — is ~2% slower (+2.33% [+0.92, +2.46] 8/8 and +1.97% [+1.30, +2.77] 7/8). It is the one shape #​4155's window cannot help, because the pinned key stops the window advancing and the store falls back to compacting as before; main carries the identical code. It is the price of removing the unbounded compaction the ordinary rotation paid.

What's Changed

• Backport the numeric parsing set to 4.x: #​3531 #​3535 #​3537 #​3538 #​3542 #​3593 by @​lahma in #​4120
• Backport #​3551 to 4.x: BigInt reads the leading plus a decimal string may carry by @​lahma in #​4121
• Backport #​3565 to 4.x: a split keeps its segments across a constraint that runs script by @​lahma in #​4122
• Backport #​3585 to 4.x: a number outside a parameter's range is no longer scored as a fit by @​lahma in #​4123
• Backport #​3778 to 4.x: BestAvailableLocale resolves a CultureInfo only when the set cannot answer by @​lahma in #​4124
• Let the white-space census admit BigInt's leading plus, which 4.x now reads by @​lahma in #​4128
• Backport #​3524 to 4.x: Collections: a rotating key set moves its window instead of compacting the array (#​3315) by @​lahma in #​4155
• Backport #​4126 to 4.x: Canonicalize every Unicode extension keyword value in Intl.Locale by @​lahma in #​4156
• Backport #​4154 to 4.x: Avoid materializing numeric modulo operands by @​lahma in #​4167
• Backport #​4163 to 4.x: Intl.Locale getWeekInfo picks its region through RegionPreference by @​lahma in #​4168
• Backport #​4165 to 4.x: Walk bound-function chains in IsConstructor and GetFunctionRealm instead of recursing by @​lahma in #​4169
• Backport #​4078 and #​4125 to 4.x: walk the prototype chain, and probe a wrapper's forward by @​lahma in #​4170

Full Changelog: sebastienros/jint@v4.16.3...v4.16.4

v4.16.3

Jint 4.16.3 is a maintenance release from the 4.x branch: correctness and conformance fixes backported from main, and nothing that changes an existing API or an existing default. If you are on 4.16.2 it is a drop-in update — every public signature is the one 4.16.0 shipped, on all five target frameworks, and the per-framework snapshots in Jint.Tests.PublicInterface/Verify/ are unchanged. main remains 5.0.0 development; what is coming there is recorded as it lands in docs/v5-migration.md.

Highlights

A long-lived engine stops accumulating what it has already run. Evaluate(string) and Execute(string) parse a fresh Script on every call, and the engine kept every one of them. Three of the four per-engine handler-tree caches already reset wholesale at 2048 entries so a host streaming endless distinct sources cannot grow them without bound; the fourth, _evaluatedScripts, never got that ceiling and held its keys strongly, retaining the AST of every distinct script the engine had ever evaluated — about 528 bytes per call, climbing forever and reclaimed by nothing short of dropping the engine (#​4116). The realm's tagged-template map had the same shape and a harder constraint: Realm._templateMap was a Dictionary<Node, JsArray>, strong on both ends and never cleared, costing roughly 1.35 KB per call for a frozen array and its raw array. A ceiling is no remedy there, because evicting a live template site is script-visible — f() === f() must hold for one site — so it becomes a ConditionalWeakTable<Node, WeakReference<JsArray>>, weak on both halves (#​4119). Both matter most to exactly the embedding that looks innocuous: one engine, kept for the lifetime of the process, handed ad-hoc source.

A suspended frame no longer dereferences what the suspension produced. await and yield suspend by returning a plain undefined, and the enclosing member link turns that into a sentinel reference that every consumer must recognise before reading. Nine did not, so they read undefined.undefined and raised a TypeError inside a frame that was already suspended. AsyncBlockStart swallowed that throw, but not before the statement-list resume position had been cleared on the way out — so the resume replayed the body from the first statement: one extra run of every un-awaited side effect per suspension point, and a re-entrancy guard silently truncating the rest. In a generator nothing swallows it and the TypeError comes straight out of next(). Two shapes were wrong answers rather than repeated ones — (await p).x = 1 rejected the promise, and o[await k] = 1 assigned to the literal key "undefined" instead of the real one — and for await ((await p).a of it) never terminated at all. Optional chaining was not the trigger despite where the report put it: the guarded fast lane needs a literal property name, so every computed member read of an awaited or yielded value fell through, (await p)[0] as much as (await p)[k] (#​4089, reported by @​salihvatanseverv in #​4086).

Verification

Every change was verified failing-first against the unfixed branch. The suspension fix is pinned by 35 new cases in Jint.Tests/Runtime/SuspendedOptionalChainTests.cs: against 4.16.2's code 28 fail and 6 pass on both .NET 10 and .NET Framework 4.7.2, with a 35th — the for await shape — hanging the test host outright rather than failing; after the fix all 35 pass on both. The retention fixes are pinned by Jint.Tests/Runtime/GarbageCollectionTests.cs and TaggedTemplateCacheTests.cs.

Release diagnostics on the tagged commit, in Release: Jint.Tests 7,170 (net10.0) and 7,085 (net472); Jint.Tests.PublicInterface 1,852 and 1,844; Jint.Tests.CommonScripts 28 and 28; Jint.Tests.SourceGenerators 52; the host-contract verification leg (JINT_HOST_CONTRACT_VERIFICATION=1) 7,170 / 7,085 and 1,856 / 1,848 — zero failures anywhere. test262: 102,498 passed, 183 skipped, with three files crossing the engine's default 30-second budget under whole-suite CPU contention and passing in three seconds when run alone.

The paired SunSpider and Dromaeo comparison against 4.16.2 was run after the tag rather than before it, which is a departure from how 4.16.2 was gated; it is recorded here because the result is what the release notes should carry, not the order it arrived in. No row regressed. Fifty-one rows, paired, alternating order, DefaultJob, on an idle machine: the three-round screen left two candidates clearing the sign-agreement and magnitude bar, both of them Dromaeo.StringBase64, and re-measuring those at eight rounds read −1.72% [−3.01, +1.98] and +0.30% [−3.10, +4.26] — no change, with a third parameter combination coming out faster. StringBase64 is the row Jint.Benchmark/AGENTS.md already documents as a three-round false positive, and it behaved as documented. The Cube control rows moved +0.6% to +0.8%, which is this machine's floor on rows the change cannot reach.

Nothing here is a performance change by intent. #​4119 does move a tagged-template lookup from a Dictionary to a ConditionalWeakTable and #​4089 adds suspension checks to several interpreter lanes, and neither is visible above the noise floor.

What's Changed

• Backport #​4115 to 4.x: bound the evaluated-script set by @​lahma in #​4116
• Backport #​4118 to 4.x: stop the realm's template map retaining every site it ran by @​lahma in #​4119
• Async and generators: a suspended frame dereferences nothing the suspension produced (backport of #​4088) by @​lahma in #​4089

Full Changelog: sebastienros/jint@v4.16.2...v4.16.3

v4.16.2

Jint 4.16.2 is a maintenance release from the 4.x branch: correctness and conformance fixes backported from main, and nothing that changes an existing API or an existing default. If you are on 4.16.1 it is a drop-in update — every public signature is the one 4.16.0 shipped, on all five target frameworks, and the per-framework snapshots in Jint.Tests.PublicInterface/Verify/ are unchanged. main remains 5.0.0 development; what is coming there is recorded as it lands in docs/v5-migration.md.

Highlights

Failures that used to end the process, or never end. A native error raised while a call's arguments are being evaluated is propagated instead of leaving an empty value behind, which on 4.16.1 could recurse until the process died — decodeURIComponent on a malformed sequence was enough (#​4009). Native recursion and the forwarding paths through bound functions and proxies are guarded so a deep native chain raises a catchable error (#​4007). A module graph too deep to link raises an error the host can catch instead of overflowing the stack (#​3548). Temporal and Intl parsing cannot throw an uncatchable RegexMatchTimeoutException because the machine was busy (#​3543), a Temporal difference past a calendar's range raises RangeError instead of spinning forever (#​3555), and the process-wide Intl culture cache and Temporal zone cache are read-only and bounded, with a rejected zone no longer remembered — closing a script-driven unbounded growth (#​3546).

Generators and built-ins, step by step. A yield* delegation reached again by a loop both re-delegates and keeps its place: countdown(3) in a loop no longer hangs, and a delegating generator no longer returns the memoized first result (#​3545). Array.prototype.map and slice hand a @@species constructor the length ToLength produced, and a non-callable map argument is a TypeError (#​3547). A trailing NUL pads neither a numeric string nor an array index (#​3552). A removed property slot is a tombstone rather than a free slot to reuse, so enumeration order survives a delete-and-readd (#​3318), and LengthOfArrayLike no longer clamps through a uint overload (#​3328).

Interop that answers for the right engine. Two engines in one process no longer decide each other's conversions and operators (#​3559), a host type converter's answer stays with the engine whose converter gave it (#​3563), and a value the host registers on a ShadowRealm — and the members its wrapper builds eagerly — belong to that realm (#​3557). Realm construction state is restored after nesting or a failure (#​4008). Overload selection is by the arguments in hand: an operator overload is chosen that way (#​3611), a params overload is chosen by the array's element type with a failing element declining rather than throwing (#​3782), an overload the argument cannot bind to is not a match, and a host operator that throws reports what it threw (#​3554). An index on a wrapped host collection is one property however it is spelled, and a member filter that hides the indexer hides it (#​3562); a read-only host collection refuses a write with a JavaScript TypeError rather than the CLR's NotSupportedException (#​3556).

Internationalization and Temporal. The Persian calendar extends into proleptic years on its 33-year cycle, so the ends of Temporal's range land in the right Persian year (#​4006); a calendar that counts Gregorian months writes their names (#​3612); and a -u- extension carrying more than one key is read whole (#​3613).

Errors. Only a string-valued stack counts as a pre-existing stack when a JavaScriptException is built, so an accessor or non-string stack on a thrown object no longer breaks error reporting (#​3677, reported by @​jeske).

Every change was verified failing-first against the unfixed branch on both .NET Framework and .NET 10, and the release was gated on a paired SunSpider and Dromaeo comparison against 4.16.1 on an idle machine: no row regressed outside run-to-run noise, most run 1–4 % faster.

What's Changed

• Backport: a removed property slot is a tombstone, not a free slot to reuse (#​3273) by @​lahma in #​3318
• Backport: LengthOfArrayLike, delete the uint overload rather than clamp it (#​3248) by @​lahma in #​3328
• Temporal and Intl parsing cannot fail because the machine was busy (#​3486) by @​lahma in #​3543
• Backport: the process-wide Intl culture cache and Temporal zone cache are read-only and bounded, and a rejected zone is not remembered by @​lahma in #​3546
• Array: map and slice hand a @​@​species constructor the length ToLength produced (#​3510) by @​lahma in #​3547
• Generators: a yield* delegation both re-delegates and keeps its place (backport of #​3506 and #​3518) by @​lahma in #​3545
• A module graph too deep to link raises an error the host can catch, instead of ending the process (#​3415) by @​lahma in #​3548
• String to number: a trailing NUL pads neither a number string nor an array index (backport of #​3544) by @​lahma in #​3552
• Interop: a host operator reports what it threw, and an overload the argument cannot bind to is not a match by @​lahma in #​3554
• Temporal: a difference past a calendar's range raises RangeError instead of spinning (#​3452) by @​lahma in #​3555
• Interop: a read-only host collection refuses script with a JavaScript error, not the CLR's own (backport of #​3385) by @​lahma in #​3556
• ShadowRealm: a value the host registers, and the members its wrapper builds eagerly, belong to that realm by @​lahma in #​3557
• Interop: two engines in one process do not decide each other's conversions and operators (backport of #​3521 and #​3526) by @​lahma in #​3559
• Interop: an index on a wrapped host collection is one property, and a filter that hides the indexer hides it by @​lahma in #​3562
• Interop: a host type converter's answer stays with the engine whose converter gave it by @​lahma in #​3563
• Interop: an operator overload is chosen by the arguments in hand (backport of #​3578) by @​lahma in #​3611
• Intl: a calendar counting Gregorian months writes their names (backport of #​3589) by @​lahma in #​3612
• Intl: a -u- extension carrying more than one key is read whole (backport of #​3594) by @​lahma in #​3613
• JavaScriptException: only a string "stack" counts as a pre-existing stack (#​3607 backport) by @​lahma in #​3677
• Interop: a params overload is chosen by the array's element type, and a failing element declines instead of throwing (#​3764) by @​lahma in #​3782
• Backport #​3751 to 4.x: Temporal: the persian calendar extends into proleptic years on the 33-year cycle by @​lahma in #​4006
• Backport #​3922 to 4.x: Restore realm construction state after nesting or failure by @​lahma in #​4008
• Backport #​3845 to 4.x: Propagate native errors during call argument evaluation by @​lahma in #​4009
• Backport #​3877 to 4.x: Guard native recursion and forwarding paths by @​lahma in #​4007

Full Changelog: sebastienros/jint@v4.16.1...v4.16.2

v4.16.1: 4.16.1

Jint 4.16.1 is the first release from the new 4.x maintenance branch, and it marks the point where the two lines separate: main is now 5.0.0 development, and 4.x is where the 4.16.x line continues.

What that means for you. If you are on 4.16.0, this is a drop-in update — it is correctness and conformance work only, no API change and no changed default. Every public signature is the same one 4.16.0 shipped, on all five target frameworks. If you want the 4.x line, take it from 4.x and expect fixes rather than features. If you want to follow where the engine is going, watch main — v5 brings breaking API changes, an opt-in WHATWG web API surface, Web Workers, Node compatibility and a raised .NET Framework floor, and every one of them is recorded as it lands in docs/v5-migration.md.

From this release onward the 4.x public surface is snapshotted per target framework in Jint.Tests.PublicInterface/Verify/, so "did the API move?" is a diff rather than a judgement call — on this branch a diff there is a bug, and comparing those files against main's is the v4→v5 delta.

Highlights

Conformance, from a suite that now runs more of test262. The staging/ directory is generated and executed for the first time (#​3016), which is roughly 2,800 additional cases — largely SpiderMonkey's own suite contributed upstream, cov

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