runtime: fix canonical call context and drop delivery semantics

docs/architecture.md

@@ -47,6 +47,17 @@ only to CM-3. A schedule-dependent assertion cannot invoke the exception:
 if two conforming schedulers can answer differently, the assertion pins a
 policy rather than semantics. Wasmtime behavior alone is insufficient.
 
+**Pending upstream stream/future assumption.** Until
+[component-model PR #719](https://github.com/WebAssembly/component-model/pull/719)
+is adjudicated, this checkout adopts only its drop-delivery rule at head
+`35e9769957627c2bee5cd445b998b08b3c652c86`; the submodule remains pinned at
+`7c676115e93cd7d54c1732d95c54c6a3de7c5ae0`. A stream event tests for peer
+drop when the event is consumed, upgrades the result to `DROPPED`, preserves
+the accumulated element count, and retires the end. A future `COMPLETED` stays
+`COMPLETED` because its payload transferred; a pending future `CANCELLED`
+upgrades to `DROPPED` with zero progress if the peer is gone. Already-delivered
+events are not rewritten. The PR's broader paired-end refactor is not adopted.
+
 ## 2. Non-goals
 
 - **WASI in the runtime core.** Providers live in the separate
@@ -321,6 +332,8 @@ Named differences from the reference or other hosts:
   This is the sole §1 corpus/reference exception,
   [CM-3](../upstream-component-model-repo-findings.md#cm-3-cancel_copy-returns-a-stale-completed-where-wasmtime-reports-cancelled).
   See `takeCancelEvent` in `runtime/src/intrinsics/stream_builtins.ts`.
+  This cancellation-time `COMPLETED`→`CANCELLED` remap is distinct from the
+  PR #719 consumption-time peer-drop upgrade above; peer drop takes precedence.
 
 ## 7. Canonical ABI decisions
 

docs/references.md

@@ -24,6 +24,11 @@ reference, and WAST corpus used by this checkout. Its principal sources are:
 
 Current upstream sources are at
 [WebAssembly/component-model](https://github.com/WebAssembly/component-model).
+The narrow provisional semantics adopted from
+[PR #719](https://github.com/WebAssembly/component-model/pull/719) are fixed to
+head `35e9769957627c2bee5cd445b998b08b3c652c86` and recorded in
+[architecture §1](architecture.md#1-goals); they do not move the submodule pin
+or adopt that PR's structural refactor.
 The [Component Model book](https://component-model.bytecodealliance.org/)
 is introductory documentation, not the semantic tie-breaker.
 Local discrepancies belong in

harness/browser/expectations/chromium.ts

@@ -17,9 +17,9 @@ export const chromium: LaneExpectation = {
   totals: {
     commands: 1511,
     executed: 1411,
-    passed: 1285,
+    passed: 1286,
     failed: 0,
-    xfail: 126,
+    xfail: 125,
     pendingRuntime: 95,
     pendingCapability: 0,
     unsupportedDirective: 5,

harness/browser/expectations/firefox.ts

@@ -21,9 +21,9 @@ export const firefox: LaneExpectation = {
   totals: {
     commands: 1511,
     executed: 1411,
-    passed: 1285,
+    passed: 1286,
     failed: 0,
-    xfail: 126,
+    xfail: 125,
     pendingRuntime: 95,
     pendingCapability: 0,
     unsupportedDirective: 5,

harness/shell/expectations/bun-pinned.ts

@@ -45,9 +45,9 @@ export const bunPinned: ShellLaneExpectation = {
   totals: {
     commands: 1511,
     executed: 1411,
-    passed: 1285,
+    passed: 1286,
     failed: 0,
-    xfail: 126,
+    xfail: 125,
     pendingRuntime: 95,
     pendingCapability: 0,
     unsupportedDirective: 5,

harness/shell/expectations/jsc-pinned.ts

@@ -21,9 +21,9 @@ export const jscPinned: ShellLaneExpectation = {
   totals: {
     commands: 1511,
     executed: 1411,
-    passed: 1285,
+    passed: 1286,
     failed: 0,
-    xfail: 126,
+    xfail: 125,
     pendingRuntime: 95,
     pendingCapability: 0,
     unsupportedDirective: 5,

harness/shell/expectations/jsc-trunk.ts

@@ -55,9 +55,9 @@ export const jscTrunk: ShellLaneExpectation = {
   totals: {
     commands: 1511,
     executed: 1411,
-    passed: 1285,
+    passed: 1286,
     failed: 0,
-    xfail: 126,
+    xfail: 125,
     pendingRuntime: 95,
     pendingCapability: 0,
     unsupportedDirective: 5,

harness/shell/expectations/node-pinned.ts

@@ -35,9 +35,9 @@ export const nodePinned: ShellLaneExpectation = {
   totals: {
     commands: 1511,
     executed: 1411,
-    passed: 1285,
+    passed: 1286,
     failed: 0,
-    xfail: 126,
+    xfail: 125,
     pendingRuntime: 95,
     pendingCapability: 0,
     unsupportedDirective: 5,

harness/shell/expectations/sm-nightly.ts

@@ -44,9 +44,9 @@ export const smNightly: ShellLaneExpectation = {
   totals: {
     commands: 1511,
     executed: 1411,
-    passed: 1285,
+    passed: 1286,
     failed: 0,
-    xfail: 126,
+    xfail: 125,
     pendingRuntime: 95,
     pendingCapability: 0,
     unsupportedDirective: 5,

harness/shell/expectations/sm-pinned.ts

@@ -24,9 +24,9 @@ export const smPinned: ShellLaneExpectation = {
   totals: {
     commands: 1511,
     executed: 1411,
-    passed: 1285,
+    passed: 1286,
     failed: 0,
-    xfail: 126,
+    xfail: 125,
     pendingRuntime: 95,
     pendingCapability: 0,
     unsupportedDirective: 5,

harness/src/wasmtime-expectations.ts

@@ -78,15 +78,6 @@ export const WASMTIME_EXPECTATION_GROUPS: readonly WasmtimeExpectationGroup[] =
             status: "failed",
           }],
         },
-        {
-          file: "async/context-in-compositions.json",
-          rows: [{
-            lines: [435, 436, 437],
-            cause:
-              "Error: expected return, got trap: cannot enter component instance 2 — instance poisoned by: Trap: guest trapped: unreachable",
-            status: "failed",
-          }],
-        },
         {
           file: "async/context-in-resource-drop.json",
           rows: [{
@@ -103,15 +94,6 @@ export const WASMTIME_EXPECTATION_GROUPS: readonly WasmtimeExpectationGroup[] =
             status: "failed",
           }],
         },
-        {
-          file: "async/stream-big-read-and-writes.json",
-          rows: [{
-            lines: [43],
-            cause:
-              'Error: expected trap "stream read/write count too large", got "cannot enter component instance 0 — instance poisoned by: RangeError: Invalid array length"',
-            status: "failed",
-          }],
-        },
         {
           file: "async/task-deletion.json",
           rows: [{
@@ -437,90 +419,6 @@ export const WASMTIME_EXPECTATION_GROUPS: readonly WasmtimeExpectationGroup[] =
     {
       class: "runtime-semantics",
       files: [
-        {
-          file: "async/context-in-compositions.json",
-          rows: [{
-            lines: [155, 434],
-            cause:
-              "Error: expected return, got trap: guest trapped: unreachable",
-            status: "failed",
-          }],
-        },
-        {
-          file: "async/error-context.json",
-          rows: [{
-            lines: [86],
-            cause: "AssertionError: store out of bounds",
-            status: "failed",
-          }],
-        },
-        {
-          file: "async/futures.json",
-          rows: [{
-            lines: [54, 64],
-            cause:
-              "AssertionError: suspension mode jspi wrapped imports without wrapping any entry (entries=false, imports=true) — a Suspending import reached from a non-promising activation traps unconditionally (jspi pin (c))",
-            status: "failed",
-          }],
-        },
-        {
-          file: "async/stackful.json",
-          rows: [{
-            lines: [110, 132],
-            cause:
-              "AssertionError: suspension mode jspi wrapped imports without wrapping any entry (entries=false, imports=true) — a Suspending import reached from a non-promising activation traps unconditionally (jspi pin (c))",
-            status: "failed",
-          }],
-        },
-        {
-          file: "async/stream-big-read-and-writes.json",
-          rows: [{
-            lines: [42],
-            cause: "RangeError: Invalid array length",
-            status: "failed",
-          }],
-        },
-        {
-          file: "async/streams.json",
-          rows: [{
-            lines: [73, 83],
-            cause:
-              "AssertionError: suspension mode jspi wrapped imports without wrapping any entry (entries=false, imports=true) — a Suspending import reached from a non-promising activation traps unconditionally (jspi pin (c))",
-            status: "failed",
-          }],
-        },
-        {
-          file: "async/sync-call-context-slots.json",
-          rows: [{
-            lines: [76, 152],
-            cause:
-              "Error: expected return, got trap: guest trapped: unreachable",
-            status: "failed",
-          }],
-        },
-        {
-          file: "async/sync-call-context.json",
-          rows: [{
-            lines: [61, 126, 207, 298, 389, 447, 544],
-            cause:
-              "Error: expected return, got trap: guest trapped: unreachable",
-            status: "failed",
-          }],
-        },
-        {
-          file: "async/task-builtins.json",
-          rows: [{
-            lines: [34, 56, 74],
-            cause:
-              "AssertionError: suspension mode jspi wrapped imports without wrapping any entry (entries=false, imports=true) — a Suspending import reached from a non-promising activation traps unconditionally (jspi pin (c))",
-            status: "failed",
-          }, {
-            lines: [201, 466, 723],
-            cause:
-              "Error: expected return, got trap: guest trapped: unreachable",
-            status: "failed",
-          }],
-        },
         {
           file: "import.json",
           rows: [{

harness/src/xfail.ts

@@ -661,32 +661,6 @@ export const XFAIL: XfailEntry[] = [
     line: 369,
     reason: "same cascade as line 355, see that entry",
   },
-  // --- async/sync-streams.json: test/async/sync-streams.wast expects three
-  // values polyengine does not produce (STARTING vs STARTED at the
-  // sync-lowered `set` call, and a COMPLETED<->DROPPED completion-code swap
-  // on the paired stream.read/write) under CM#705's blocking semantics, so
-  // the file's single all-in-one assert_return hits a guest `unreachable`.
-  // Classed `cm705-sync-sched`
-  // (https://github.com/polymorph-components/polyengine/issues/249).
-  //
-  // For the rest of the file polyengine implements wasmtime's model (#43):
-  // the async-lowered call's initial status is decided only after the callee
-  // instance's runnable work has been drained to quiescence — by which time
-  // the producer has exited and the next task reports STARTED. Adjudicated
-  // 2026-08-10 (issue #43): the test's hard STARTED assertion is
-  // schedule-dependent — an upstream test defect overfitting wasmtime's
-  // deferred-entry policy (pristine definitions.py answers STARTING) — and
-  // polyengine's drain policy satisfies it as written under any seed. ---
-  {
-    file: "async/sync-streams.json",
-    line: 208,
-    reason:
-      "expected return, got trap: guest trapped: unreachable — this file's " +
-      "expected STARTING/STARTED and COMPLETED/DROPPED codes track CM#705's " +
-      "blocking semantics, which polyengine's sync scheduling does not yet " +
-      "produce, so the guest's own assertion traps; cm705-sync-sched, " +
-      "https://github.com/polymorph-components/polyengine/issues/249",
-  },
   // --- async/trap-if-block-and-sync.json: (history: at the prior pin the
   // whole file was blocked by the now-exited wasmparser/wast pin-drift
   // class — see the EXIT note at the top of this file, $Tester's canonical

runtime/src/exec/boundary.ts

@@ -58,6 +58,7 @@
   Thread,
   WaitableSet,
   withActivation,
+  withSynchronousActivation,
 } from "../task/mod.ts";
 import { currentTask } from "../task/scheduler.ts";
 import type {
@@ -218,8 +219,14 @@
     stringEncoding: opts.stringEncoding,
     memory: opts.memory,
     realloc: opts.realloc === null ? null : (o, os, a, n) => {
       const realloc = require(opts.realloc, "realloc")!;
-      const p = callCore(realloc, [o, os, a, n]);
+      // definitions.py LiftLowerContext.reallocate creates and invokes a fresh
+      // sync canon_lift (lines 642-658), hence fresh task/thread context. Keep
+      // post-return on its originating task; only realloc takes this boundary.
+      const p = withSynchronousActivation(
+        opts.instance,
+        () => callCore(realloc, [o, os, a, n]),
+      );
       trapIf(p.length !== 1 || typeof p[0] !== "number", "realloc result");
       return (p[0] as number) >>> 0;
     },
@@ -1657,7 +1664,7 @@
     task.return_(results);
     // Post-return runs after the results were read out of guest memory,
     // with may_leave cleared (reference canon_lift).
     const postReturn = require(opts.postReturn, `${name} post-return`);
     if (postReturn !== null) {
       assert_(inst.mayLeave, "post-return with may_leave already false");
       inst.mayLeave = false;
@@ -1686,7 +1693,7 @@
   // Callback ABI waits between invocations without JSPI, but callbacks in
   // JSPI mode need the same promising wrapper as the initial core entry.
   const callback = enterWasm(
     require(opts.callback, `${name} callback`)!,
     input.mode,
   );
   const [packed] = normalizeCoreValues(