test: link a prebuilt runtime into fixture bundles

.mocharc.parallel.cjs

@@ -7,5 +7,8 @@ module.exports = {
   ...base,
   bail: false,
   timeout: 30000,
+  // V8's default limit sits above `MARKO_TEST_WORKER_MEM`, so a worker hands its
+  // slice to a fresh process before collecting; a major GC is the cheaper trade.
+  "node-option": [...base["node-option"], "max-old-space-size=2048"],
   require: [...base.require, "./scripts/test-parallel-worker.cjs"],
 };

agent-feedback/items/2026-08-30-measure-optimize-sizes-without-bundling-the-runtime.md

@@ -0,0 +1,21 @@
+---
+type: perf
+impact: med
+effort: high
+site: packages/runtime-tags/src/__tests__/utils/bundle.ts › externalRuntimePlugin
+---
+
+# Measure optimize sizes without bundling the runtime into every fixture
+
+The optimize dom build re-emits and tree-shakes the whole runtime for every
+fixture, because `sizes.json` records minified chunk totals and those totals
+only exist if the runtime sits in the chunk. It is the one fixture build that
+cannot link the prebuilt runtime as an external, and it dominates what bundling
+costs the suite.
+
+Measuring a chunk's shared-runtime share once per process and adding it to the
+fixture's own tree-shaken bytes would let that build take the external too.
+
+Check: in `createBuilds`, extend `externalRuntimePlugin` to the optimize dom
+build and time `pnpm run test:parallel`; the fixture `sizes.json` assertions are
+what fail.

agent-feedback/items/2026-08-30-pool-jsdom-windows-across-fixtures.md

@@ -0,0 +1,22 @@
+---
+type: perf
+impact: low
+effort: high
+site: packages/runtime-tags/src/__tests__/utils/create-browser.ts › createBrowser
+---
+
+# Pool jsdom windows across fixtures
+
+`createBrowser` builds a fresh `JSDOM` for each of a fixture's ssr and csr runs
+and jsdom re-installs every Web IDL class onto the new realm each time, which
+is ~10% of the test worker's main-thread inclusive cost. A pool recovers under
+3% of wall, though, because the reset it needs is most of the cost it saves,
+and the reset is hard to get right: clearing the realm's added globals (the
+resume registry is a global named for the runtime id), replacing the document,
+dropping the `importWithContext` module cache and cancelling tracked timers
+still leaves fixtures reading each other's counters. Worth revisiting only with
+a reset that is provably complete, since a leak is a cross-fixture correctness
+bug rather than a slow test.
+
+Check: `--cpu-prof` one worker of `node scripts/test-parallel.js` and read the
+inclusive cost of `exports.createWindow`.

agent-feedback/items/2026-08-30-schedule-test-parallel-slices-dynamically.md

@@ -0,0 +1,21 @@
+---
+type: perf
+impact: med
+effort: high
+site: scripts/test-parallel.js › packBins
+---
+
+# Schedule test-parallel slices dynamically
+
+`packBins` assigns every slice up front and assumes each costs the same, so a
+run finishes when its unluckiest worker does: on four cores the workers land
+around 35s, 36s, 38s and 41s, and the last one sets the wall time. The spread
+is fixture cost variance, not slicing granularity — raising `SLOT_TOTAL` from
+`WORKERS * 16` to `WORKERS * 256` leaves it unchanged, since each worker
+already runs ~280 fixtures. Recovering the tail needs workers to claim slices
+as they free up rather than owning a fixed set, which the suites' `beforeEach`
+skip hook could already express; the hard part is that mocha registers every
+suite at load time, so a claim has to be cheap enough to run per suite.
+
+Check: `taskset -c 0-3 node scripts/test-parallel.js` and compare the per-worker
+times it prints.

agent-feedback/items/2026-08-31-capture-console-patches-a-process-global.md

@@ -0,0 +1,19 @@
+---
+type: cleanup
+impact: low
+effort: medium
+site: packages/runtime-tags/src/__tests__/utils/capture-console.ts
+---
+
+# `captureConsole` records through a process global
+
+The no-argument `captureConsole()` swaps `globalThis.console`, so anything that
+logs while a window is open is attributed to whichever fixture happens to be
+rendering. Nothing does today — the jsdom path gets its own `virtualConsole`,
+the compiler reports through diagnostics, and a fixture's bundles are awaited
+before its window opens — but that is a set of separate guarantees rather than
+one property, and each new concurrent logger has to rediscover it.
+
+The server render already runs in a `vm` context (`importWithContext`), so it
+could take a per-realm `console` the way the jsdom path does, and capture would
+stop depending on what else is running.

agent-feedback/items/2026-09-01-pipeline-fixture-builds-into-worker-idle.md

@@ -0,0 +1,23 @@
+---
+type: perf
+impact: med
+effort: high
+site: packages/runtime-tags/src/__tests__/main.test.ts › ssrRunner
+---
+
+# Pipeline the next fixture build into the worker's idle time
+
+A `--cpu-prof` of one `test:parallel` worker running `main.test.ts` alone
+spends 32% of its wall time in `(idle)`: `createServerRunner` awaits rolldown,
+whose work runs on native threads while the JS thread has nothing to do. With
+one worker per core the other workers absorb some of that, but the run still
+sits at ~80% core utilization, so the gap is the largest remaining bucket.
+
+Building the next mode's (or fixture's) runner one step ahead of the tests that
+consume it would overlap that wait with test work. What blocks it is that
+`captureConsole()` swaps `globalThis.console`, so a build's compiler output
+would land in whichever fixture is rendering (see the capture-console item).
+
+Check: `node --cpu-prof --experimental-vm-modules node_modules/mocha/bin/_mocha
+--config .mocharc.parallel.cjs packages/runtime-tags/src/__tests__/main.test.ts`
+and read the `(idle)` share of self time.

packages/runtime-tags/src/__tests__/fixtures-interop/error-serialize-promise-class-to-tags/__snapshots__/html.bundle.debug.js

@@ -7,7 +7,7 @@ var tags_child_default = _template("__tests__/components/tags-child.marko", (inp
 	let pending = Promise.resolve("hi");
 	_html(`<button id=tags>go</button>${_el_resume($scope0_id, "#button/0")}`);
 	_script($scope0_id, "__tests__/components/tags-child.marko_0");
-	writeScope($scope0_id, { pending }, "__tests__/components/tags-child.marko", 0, { pending: "2:6" });
+	_scope($scope0_id, { pending }, "__tests__/components/tags-child.marko", 0, { pending: "2:6" });
 	_resume_branch($scope0_id);
 });
 

packages/runtime-tags/src/__tests__/fixtures-interop/error-serialize-promise-class-to-tags/__snapshots__/html.bundle.js

@@ -7,7 +7,7 @@ var tags_child_default = _template("b", (input) => {
 	let pending = Promise.resolve("hi");
 	_html(`<button id=tags>go</button>${_el_resume($scope0_id, "a")}`);
 	_script($scope0_id, "b0");
-	writeScope($scope0_id, { b: pending });
+	_scope($scope0_id, { b: pending });
 	_resume_branch($scope0_id);
 });
 

packages/runtime-tags/src/__tests__/fixtures-interop/error-unserializable-class-to-tags/__snapshots__/html.bundle.debug.js

@@ -7,7 +7,7 @@ var tags_child_default = _template("__tests__/components/tags-child.marko", (inp
 	let count = 0;
 	_html(`<button id=tags>${_text_resume($scope0_id, "#text/1", count)}</button>${_el_resume($scope0_id, "#button/0")}`);
 	_script($scope0_id, "__tests__/components/tags-child.marko_0");
-	writeScope($scope0_id, {
+	_scope($scope0_id, {
 		input_data: input.data,
 		count
 	}, "__tests__/components/tags-child.marko", 0, {

packages/runtime-tags/src/__tests__/fixtures-interop/interop-attr-tags-tags-to-class/__snapshots__/dom.bundle.debug.js

@@ -1,5 +1,5 @@
 // v:template.marko.hydrate-6.js
-var v_template_marko_hydrate_6_default = () => init$1();
+var v_template_marko_hydrate_6_default = () => init();
 
 // v:template.marko.hydrate-5.js
 var import_components = require_components();

packages/runtime-tags/src/__tests__/fixtures-interop/interop-attr-tags-tags-to-class/__snapshots__/html.bundle.debug.js

@@ -64,6 +64,6 @@ var template_default = _template("__tests__/template.marko", (input) => {
 		})
 	});
 	_script($scope0_id, "__tests__/template.marko_0");
-	writeScope($scope0_id, { count }, "__tests__/template.marko", 0, { count: "1:6" });
+	_scope($scope0_id, { count }, "__tests__/template.marko", 0, { count: "1:6" });
 	_resume_branch($scope0_id);
 }, 1);

packages/runtime-tags/src/__tests__/fixtures-interop/interop-await-class-to-tags/__snapshots__/dom.bundle.debug.js

@@ -1,4 +1,5 @@
 // components/tags-child.marko
+var import_vdom = require_vdom();
 const $template = "<!><!><!>";
 const $walks = "b%c";
 const $await_content__value = ($scope, value) => _text($scope["#text/0"], value);

packages/runtime-tags/src/__tests__/fixtures-interop/interop-basic-class-to-tags/__snapshots__/html.bundle.debug.js

@@ -7,7 +7,7 @@ var tags_counter_default = _template("__tests__/components/tags-counter.marko",
 	let count = 0;
 	_html(`<button id=tags${_attr("data-parent", input.count)}>${_text_resume($scope0_id, "#text/1", count)}</button>${_el_resume($scope0_id, "#button/0")}`);
 	_script($scope0_id, "__tests__/components/tags-counter.marko_0");
-	writeScope($scope0_id, { count }, "__tests__/components/tags-counter.marko", 0, { count: "1:6" });
+	_scope($scope0_id, { count }, "__tests__/components/tags-counter.marko", 0, { count: "1:6" });
 	_resume_branch($scope0_id);
 });
 

packages/runtime-tags/src/__tests__/fixtures-interop/interop-basic-class-to-tags/__snapshots__/html.bundle.js

@@ -7,7 +7,7 @@ var tags_counter_default = _template("b", (input) => {
 	let count = 0;
 	_html(`<button id=tags${_attr("data-parent", input.count)}>${_text_resume($scope0_id, "b", count)}</button>${_el_resume($scope0_id, "a")}`);
 	_script($scope0_id, "b0");
-	writeScope($scope0_id, { f: count });
+	_scope($scope0_id, { f: count });
 	_resume_branch($scope0_id);
 });
 

packages/runtime-tags/src/__tests__/fixtures-interop/interop-basic-tags-to-class/__snapshots__/dom.bundle.debug.js

@@ -1,5 +1,5 @@
 // v:template.marko.hydrate-6.js
-var v_template_marko_hydrate_6_default = () => init$1();
+var v_template_marko_hydrate_6_default = () => init();
 
 // v:template.marko.hydrate-5.js
 var import_components = require_components();

packages/runtime-tags/src/__tests__/fixtures-interop/interop-basic-tags-to-class/__snapshots__/html.bundle.debug.js

@@ -30,6 +30,6 @@ var template_default = _template("__tests__/template.marko", (input) => {
 	_html(`<button id=tags>${_text_resume($scope0_id, "#text/1", count)}</button>${_el_resume($scope0_id, "#button/0")}`);
 	_dynamic_tag($scope0_id, "#text/2", _marko_template, { count });
 	_script($scope0_id, "__tests__/template.marko_0");
-	writeScope($scope0_id, { count }, "__tests__/template.marko", 0, { count: "1:6" });
+	_scope($scope0_id, { count }, "__tests__/template.marko", 0, { count: "1:6" });
 	_resume_branch($scope0_id);
 }, 1);

packages/runtime-tags/src/__tests__/fixtures-interop/interop-basic-tags-to-class/__snapshots__/html.bundle.js

@@ -24,6 +24,6 @@ var template_default = _template("a", (input) => {
 	_html(`<button id=tags>${_text_resume($scope0_id, "b", count)}</button>${_el_resume($scope0_id, "a")}`);
 	_dynamic_tag($scope0_id, "c", _marko_template, { count });
 	_script($scope0_id, "a0");
-	writeScope($scope0_id, { d: count });
+	_scope($scope0_id, { d: count });
 	_resume_branch($scope0_id);
 }, 1);

packages/runtime-tags/src/__tests__/fixtures-interop/interop-basic-tags-to-inert-class/__snapshots__/html.bundle.debug.js

@@ -22,6 +22,6 @@ var template_default = _template("__tests__/template.marko", (input) => {
 	_html(`<button id=tags>${_text_resume($scope0_id, "#text/1", count)}</button>${_el_resume($scope0_id, "#button/0")}`);
 	_dynamic_tag($scope0_id, "#text/2", _marko_template, { value: "Hello World" }, 0, 0, 0);
 	_script($scope0_id, "__tests__/template.marko_0");
-	writeScope($scope0_id, { count }, "__tests__/template.marko", 0, { count: "1:6" });
+	_scope($scope0_id, { count }, "__tests__/template.marko", 0, { count: "1:6" });
 	_resume_branch($scope0_id);
 }, 1);

packages/runtime-tags/src/__tests__/fixtures-interop/interop-basic-tags-to-inert-class/__snapshots__/html.bundle.js

@@ -18,6 +18,6 @@ var template_default = _template("a", (input) => {
 	_html(`<button id=tags>${_text_resume($scope0_id, "b", count)}</button>${_el_resume($scope0_id, "a")}`);
 	_dynamic_tag($scope0_id, "c", _marko_template, { value: "Hello World" }, 0, 0, 0);
 	_script($scope0_id, "a0");
-	writeScope($scope0_id, { d: count });
+	_scope($scope0_id, { d: count });
 	_resume_branch($scope0_id);
 }, 1);

packages/runtime-tags/src/__tests__/fixtures-interop/interop-camel-events-tags-to-class/__snapshots__/dom.bundle.debug.js

@@ -1,5 +1,5 @@
 // v:template.marko.hydrate-6.js
-var v_template_marko_hydrate_6_default = () => init$1();
+var v_template_marko_hydrate_6_default = () => init();
 
 // v:template.marko.hydrate-5.js
 var import_components = require_components();

packages/runtime-tags/src/__tests__/fixtures-interop/interop-camel-events-tags-to-class/__snapshots__/html.bundle.debug.js

@@ -28,6 +28,6 @@ var template_default = _template("__tests__/template.marko", (input) => {
 		}, "__tests__/template.marko_0/onValueChanged", $scope0_id)
 	}, 0, 0, 0);
 	_html(`<div id=tags-api>${_text_resume($scope0_id, "#text/1", received)}</div>`);
-	writeScope($scope0_id, {}, "__tests__/template.marko", 0);
+	_scope($scope0_id, {}, "__tests__/template.marko", 0);
 	_resume_branch($scope0_id);
 }, 1);

packages/runtime-tags/src/__tests__/fixtures-interop/interop-camel-events-tags-to-class/__snapshots__/html.bundle.js

@@ -22,6 +22,6 @@ var template_default = _template("a", (input) => {
 		}, "a0", $scope0_id)
 	}, 0, 0, 0);
 	_html(`<div id=tags-api>${_text_resume($scope0_id, "b", received)}</div>`);
-	writeScope($scope0_id, {});
+	_scope($scope0_id, {});
 	_resume_branch($scope0_id);
 }, 1);

packages/runtime-tags/src/__tests__/fixtures-interop/interop-class-to-tags-import/__snapshots__/html.bundle.debug.js

@@ -6,7 +6,7 @@ var tags_counter_default = _template("__tests__/components/tags-counter.marko",
 	let count = 0;
 	_html(`<button id=tags${_attr("data-parent", input.count)}>${_text_resume($scope0_id, "#text/1", count)}</button>${_el_resume($scope0_id, "#button/0")}`);
 	_script($scope0_id, "__tests__/components/tags-counter.marko_0");
-	writeScope($scope0_id, { count }, "__tests__/components/tags-counter.marko", 0, { count: "1:6" });
+	_scope($scope0_id, { count }, "__tests__/components/tags-counter.marko", 0, { count: "1:6" });
 	_resume_branch($scope0_id);
 });
 

packages/runtime-tags/src/__tests__/fixtures-interop/interop-class-to-tags-import/__snapshots__/html.bundle.js

@@ -6,7 +6,7 @@ var tags_counter_default = _template("b", (input) => {
 	let count = 0;
 	_html(`<button id=tags${_attr("data-parent", input.count)}>${_text_resume($scope0_id, "b", count)}</button>${_el_resume($scope0_id, "a")}`);
 	_script($scope0_id, "b0");
-	writeScope($scope0_id, { f: count });
+	_scope($scope0_id, { f: count });
 	_resume_branch($scope0_id);
 });
 

packages/runtime-tags/src/__tests__/fixtures-interop/interop-content-event-tags-to-class/__snapshots__/html.bundle.debug.js

@@ -39,7 +39,7 @@ var tags_mid_default = _template("__tests__/components/tags-mid.marko", (input)
 		_html("<span>deep body</span>");
 	}, $scope0_id));
 	_script($scope0_id, "__tests__/components/tags-mid.marko_0");
-	writeScope($scope0_id, { count }, "__tests__/components/tags-mid.marko", 0, { count: "2:6" });
+	_scope($scope0_id, { count }, "__tests__/components/tags-mid.marko", 0, { count: "2:6" });
 	_resume_branch($scope0_id);
 });
 

packages/runtime-tags/src/__tests__/fixtures-interop/interop-deprecated-core-tag-migrate/__snapshots__/html.bundle.debug.js

@@ -7,7 +7,7 @@ var template_default = _template("__tests__/template.marko", (input) => {
 	_html(`<button id=inc>inc</button>${_el_resume($scope0_id, "#button/0")}<div id=out></div>`);
 	_script($scope0_id, "__tests__/template.marko_0_greeting#3_count#4");
 	_script($scope0_id, "__tests__/template.marko_0");
-	writeScope($scope0_id, {
+	_scope($scope0_id, {
 		greeting,
 		count
 	}, "__tests__/template.marko", 0, {

packages/runtime-tags/src/__tests__/fixtures-interop/interop-deprecated-core-tag-migrate/__snapshots__/html.bundle.js

@@ -7,7 +7,7 @@ var template_default = _template("a", (input) => {
 	_html(`<button id=inc>inc</button>${_el_resume($scope0_id, "a")}<div id=out></div>`);
 	_script($scope0_id, "a0");
 	_script($scope0_id, "a1");
-	writeScope($scope0_id, {
+	_scope($scope0_id, {
 		d: greeting,
 		e: count
 	});

packages/runtime-tags/src/__tests__/fixtures-interop/interop-duplicate-class-tag-registration/__snapshots__/dom.bundle.debug.js

@@ -1,5 +1,5 @@
 // v:template.marko.hydrate-6.js
-var v_template_marko_hydrate_6_default = () => init$1();
+var v_template_marko_hydrate_6_default = () => init();
 
 // v:template.marko.hydrate-5.js
 var import_components = require_components();

packages/runtime-tags/src/__tests__/fixtures-interop/interop-duplicate-class-tag-registration/__snapshots__/html.bundle.debug.js

@@ -31,6 +31,6 @@ var template_default = _template("__tests__/template.marko", (input) => {
 	_dynamic_tag($scope0_id, "#text/2", _marko_template, { count });
 	_dynamic_tag($scope0_id, "#text/3", _marko_template, { count });
 	_script($scope0_id, "__tests__/template.marko_0");
-	writeScope($scope0_id, { count }, "__tests__/template.marko", 0, { count: "1:6" });
+	_scope($scope0_id, { count }, "__tests__/template.marko", 0, { count: "1:6" });
 	_resume_branch($scope0_id);
 }, 1);

packages/runtime-tags/src/__tests__/fixtures-interop/interop-duplicate-class-tag-registration/__snapshots__/html.bundle.js

@@ -25,6 +25,6 @@ var template_default = _template("a", (input) => {
 	_dynamic_tag($scope0_id, "c", _marko_template, { count });
 	_dynamic_tag($scope0_id, "d", _marko_template, { count });
 	_script($scope0_id, "a0");
-	writeScope($scope0_id, { e: count });
+	_scope($scope0_id, { e: count });
 	_resume_branch($scope0_id);
 }, 1);

packages/runtime-tags/src/__tests__/fixtures-interop/interop-dynamic-tag-class-to-tags/__snapshots__/html.bundle.debug.js

@@ -6,7 +6,7 @@ var tags_child_default = _template("__tests__/components/tags-child.marko", (inp
 	let count = 0;
 	_html(`<button id=tags>${_text_resume($scope0_id, "#text/1", count)}</button>${_el_resume($scope0_id, "#button/0")}`);
 	_script($scope0_id, "__tests__/components/tags-child.marko_0");
-	writeScope($scope0_id, { count }, "__tests__/components/tags-child.marko", 0, { count: "2:6" });
+	_scope($scope0_id, { count }, "__tests__/components/tags-child.marko", 0, { count: "2:6" });
 	_resume_branch($scope0_id);
 });
 

packages/runtime-tags/src/__tests__/fixtures-interop/interop-dynamic-tag-class-to-tags/__snapshots__/html.bundle.js

@@ -6,7 +6,7 @@ var tags_child_default = _template("b", (input) => {
 	let count = 0;
 	_html(`<button id=tags>${_text_resume($scope0_id, "b", count)}</button>${_el_resume($scope0_id, "a")}`);
 	_script($scope0_id, "b0");
-	writeScope($scope0_id, { c: count });
+	_scope($scope0_id, { c: count });
 	_resume_branch($scope0_id);
 });
 

packages/runtime-tags/src/__tests__/fixtures-interop/interop-dynamic-tag-conditional-class-to-tags/__snapshots__/html.bundle.debug.js

@@ -6,7 +6,7 @@ var tags_child_default = _template("__tests__/components/tags-child.marko", (inp
 	let count = 0;
 	_html(`<button id=tags>${_text_resume($scope0_id, "#text/1", count)}</button>${_el_resume($scope0_id, "#button/0")}`);
 	_script($scope0_id, "__tests__/components/tags-child.marko_0");
-	writeScope($scope0_id, { count }, "__tests__/components/tags-child.marko", 0, { count: "2:6" });
+	_scope($scope0_id, { count }, "__tests__/components/tags-child.marko", 0, { count: "2:6" });
 	_resume_branch($scope0_id);
 });
 

packages/runtime-tags/src/__tests__/fixtures-interop/interop-dynamic-tag-conditional-class-to-tags/__snapshots__/html.bundle.js

@@ -6,7 +6,7 @@ var tags_child_default = _template("b", (input) => {
 	let count = 0;
 	_html(`<button id=tags>${_text_resume($scope0_id, "b", count)}</button>${_el_resume($scope0_id, "a")}`);
 	_script($scope0_id, "b0");
-	writeScope($scope0_id, { c: count });
+	_scope($scope0_id, { c: count });
 	_resume_branch($scope0_id);
 });
 

packages/runtime-tags/src/__tests__/fixtures-interop/interop-emit-inline-tags-to-class/__snapshots__/dom.bundle.debug.js

@@ -1,5 +1,5 @@
 // v:template.marko.hydrate-6.js
-var v_template_marko_hydrate_6_default = () => init$1();
+var v_template_marko_hydrate_6_default = () => init();
 
 // v:template.marko.hydrate-5.js
 var import_components = require_components();

packages/runtime-tags/src/__tests__/fixtures-interop/interop-emit-inline-tags-to-class/__snapshots__/html.bundle.debug.js

@@ -29,6 +29,6 @@ var template_default = _template("__tests__/template.marko", (input) => {
 		_html("Reset");
 	}, $scope0_id), 0, 0);
 	_html(`<div id=tags-api>${_text_resume($scope0_id, "#text/1", msg)}</div>`);
-	writeScope($scope0_id, {}, "__tests__/template.marko", 0);
+	_scope($scope0_id, {}, "__tests__/template.marko", 0);
 	_resume_branch($scope0_id);
 }, 1);

packages/runtime-tags/src/__tests__/fixtures-interop/interop-emit-inline-tags-to-class/__snapshots__/html.bundle.js

@@ -25,6 +25,6 @@ var template_default = _template("a", (input) => {
 		_html("Reset");
 	}, $scope0_id), 0, 0);
 	_html(`<div id=tags-api>${_text_resume($scope0_id, "b", msg)}</div>`);
-	writeScope($scope0_id, {});
+	_scope($scope0_id, {});
 	_resume_branch($scope0_id);
 }, 1);

packages/runtime-tags/src/__tests__/fixtures-interop/interop-emit-split-tags-to-class/__snapshots__/dom.bundle.debug.js

@@ -1,5 +1,5 @@
 // v:template.marko.hydrate-6.js
-var v_template_marko_hydrate_6_default = () => init$1();
+var v_template_marko_hydrate_6_default = () => init();
 
 // v:template.marko.hydrate-5.js
 var import_components = require_components();