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| 1 | +/** |
| 2 | + * Regression tests for #3122 — superseded async-iterable flights must close |
| 3 | + * (`it.return()`) at supersede time, not when the SUPERSEDING flight settles. |
| 4 | + * |
| 5 | + * The iterator close is registered as an owner cleanup, and a recompute |
| 6 | + * whose disposal rides the zombie-deferred channel only drains it at |
| 7 | + * commitPendingNode — which a verdict-held write defers until the new |
| 8 | + * flight lands. Iterator close is the cancellation hook for anything |
| 9 | + * resource-shaped behind an async iterable (fibers, sockets, subscriptions), |
| 10 | + * so the flight teardown now also fires at the `_inFlight` release site in |
| 11 | + * recompute, keyed to flight identity. The owner-cleanup registration stays |
| 12 | + * as the death backstop (close is idempotent). |
| 13 | + */ |
| 14 | +import { describe, expect, it } from "vitest"; |
| 15 | +import { |
| 16 | + createEffect, |
| 17 | + createLoadingBoundary, |
| 18 | + createMemo, |
| 19 | + createRoot, |
| 20 | + createSignal, |
| 21 | + flush, |
| 22 | + isPending, |
| 23 | + latest |
| 24 | +} from "../src/index.js"; |
| 25 | + |
| 26 | +function trackedSource(label: string, events: string[]) { |
| 27 | + let land!: () => void; |
| 28 | + const source: AsyncIterable<string> & { land: () => void } = { |
| 29 | + land: () => land(), |
| 30 | + [Symbol.asyncIterator]() { |
| 31 | + events.push(`open ${label}`); |
| 32 | + let done = false; |
| 33 | + return { |
| 34 | + next: () => |
| 35 | + new Promise<IteratorResult<string>>(resolve => { |
| 36 | + land = () => { |
| 37 | + if (done) return resolve({ done: true, value: undefined }); |
| 38 | + done = true; |
| 39 | + events.push(`land ${label}`); |
| 40 | + resolve({ done: false, value: label }); |
| 41 | + }; |
| 42 | + }), |
| 43 | + return: async () => { |
| 44 | + events.push(`close ${label}`); |
| 45 | + done = true; |
| 46 | + return { done: true as const, value: undefined }; |
| 47 | + } |
| 48 | + }; |
| 49 | + } |
| 50 | + }; |
| 51 | + return source; |
| 52 | +} |
| 53 | + |
| 54 | +const microtasks = async () => { |
| 55 | + await Promise.resolve(); |
| 56 | + await Promise.resolve(); |
| 57 | + await Promise.resolve(); |
| 58 | + flush(); |
| 59 | +}; |
| 60 | + |
| 61 | +describe("superseded iterator close timing (#3122)", () => { |
| 62 | + it("closes the stale iterator at supersede even under a loading boundary with isPending", async () => { |
| 63 | + const events: string[] = []; |
| 64 | + const sources = new Map<string, ReturnType<typeof trackedSource>>(); |
| 65 | + let setQ!: (v: string) => void; |
| 66 | + let dispose!: () => void; |
| 67 | + |
| 68 | + createRoot(d => { |
| 69 | + dispose = d; |
| 70 | + const [q, set] = createSignal(""); |
| 71 | + setQ = set; |
| 72 | + const m = createMemo(() => { |
| 73 | + const v = q(); |
| 74 | + if (!v) return [] as unknown as AsyncIterable<string>; |
| 75 | + const src = trackedSource(v, events); |
| 76 | + sources.set(v, src); |
| 77 | + return src; |
| 78 | + }); |
| 79 | + // The issue's failing shape: boundary content reading BOTH isPending |
| 80 | + // and latest over the same source. |
| 81 | + const view = createLoadingBoundary( |
| 82 | + () => { |
| 83 | + try { |
| 84 | + const pending = isPending(() => m()); |
| 85 | + return { pending, value: latest(() => m()) }; |
| 86 | + } catch { |
| 87 | + return undefined; |
| 88 | + } |
| 89 | + }, |
| 90 | + () => "loading-fallback" |
| 91 | + ); |
| 92 | + createEffect( |
| 93 | + () => view(), |
| 94 | + () => {} |
| 95 | + ); |
| 96 | + }); |
| 97 | + flush(); |
| 98 | + |
| 99 | + setQ("a"); |
| 100 | + flush(); |
| 101 | + expect(events).toEqual(["open a"]); |
| 102 | + |
| 103 | + // Supersede before 'a' lands: the stale iterator must close NOW, not |
| 104 | + // after 'ab' settles. |
| 105 | + setQ("ab"); |
| 106 | + flush(); |
| 107 | + await microtasks(); |
| 108 | + expect(events).toEqual(["open a", "close a", "open ab"]); |
| 109 | + |
| 110 | + sources.get("ab")!.land(); |
| 111 | + await microtasks(); |
| 112 | + expect(events).toEqual(["open a", "close a", "open ab", "land ab"]); |
| 113 | + |
| 114 | + // The closed stale flight can no longer land a value. |
| 115 | + sources.get("a")!.land(); |
| 116 | + await microtasks(); |
| 117 | + expect(events).toEqual(["open a", "close a", "open ab", "land ab"]); |
| 118 | + dispose(); |
| 119 | + }); |
| 120 | + |
| 121 | + it("closes the stale iterator at supersede for a plain reader too", async () => { |
| 122 | + const events: string[] = []; |
| 123 | + const sources = new Map<string, ReturnType<typeof trackedSource>>(); |
| 124 | + let setQ!: (v: string) => void; |
| 125 | + let dispose!: () => void; |
| 126 | + |
| 127 | + createRoot(d => { |
| 128 | + dispose = d; |
| 129 | + const [q, set] = createSignal("a"); |
| 130 | + setQ = set; |
| 131 | + const m = createMemo(() => { |
| 132 | + const v = q(); |
| 133 | + const src = trackedSource(v, events); |
| 134 | + sources.set(v, src); |
| 135 | + return src; |
| 136 | + }); |
| 137 | + createEffect( |
| 138 | + () => { |
| 139 | + try { |
| 140 | + return latest(() => m()); |
| 141 | + } catch { |
| 142 | + return undefined; |
| 143 | + } |
| 144 | + }, |
| 145 | + () => {} |
| 146 | + ); |
| 147 | + }); |
| 148 | + flush(); |
| 149 | + expect(events).toEqual(["open a"]); |
| 150 | + |
| 151 | + setQ("b"); |
| 152 | + flush(); |
| 153 | + await microtasks(); |
| 154 | + expect(events).toEqual(["open a", "close a", "open b"]); |
| 155 | + |
| 156 | + sources.get("b")!.land(); |
| 157 | + await microtasks(); |
| 158 | + expect(events).toEqual(["open a", "close a", "open b", "land b"]); |
| 159 | + dispose(); |
| 160 | + }); |
| 161 | +}); |
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