script: Use unrooted iterators for HTMLCollections by Narfinger · Pull Request #45582 · servo/servo

Narfinger · 2026-06-11T12:06:53Z

This implements two new UnrootedIterators (PreceedingNodeIterator and FollowingNodeIterator) with the same schema as the other UnrootedIterators.
This also implements using these iterators for HTMLCollections (and their subtypes) and CollectionSource trait as well as a couple of downstream.

Special care should be given to check:

The correctness of the new iterators from the point of iterating.
The enum CollectioonKind not having the 'static lifetime anymore.
HTMLFormControlsCollection::NamedItem (which had to be rewritten to make the lifetimes work).
Bugfix in codegen.py to also check the cx._no_gcMethods for Length(cx).
Implementation of PartialEq for UnrootedDom and UnrootedDom==T

Most other changes are mechanical &JSContext adding or NoGC propagating.

Overall this seems to eliminate rooting overhead on amazon.com down from 1.8% runtime in a small unscientific test.

Testing: WPT tests should find any screwups.

github-actions · 2026-06-11T12:14:08Z

🔨 Triggering try run (#27345803471) for Linux (WPT)

github-actions · 2026-06-11T12:59:16Z

Test results for linux-wpt from try job (#27345803471):

Flaky unexpected result (54)

OK /IndexedDB/idbtransaction-oncomplete.any.worker.html (#42804)

FAIL [expected PASS] subtest: IDBTransaction - complete event

assert_array_equals: lengths differ, expected array ["upgradeneeded", "complete", "success", "opencursor"] length 4, got ["upgradeneeded", "complete", "success"] length 3

CRASH [expected OK] /_mozilla/mozilla/focus-scroll-when-visible.html
CRASH [expected OK] /_webgl/conformance/glsl/implicit/divide_int_mat2.vert.html
TIMEOUT [expected CRASH] /content-security-policy/inheritance/blob-url-in-main-window-self-navigate-inherits.sub.html (#41490)
TIMEOUT [expected OK] /content-security-policy/inheritance/document-write-iframe.html (#41195)
- TIMEOUT [expected PASS] subtest: document.open() keeps inherited CSPs on transient about:blank.
```
Test timed out
```
OK [expected CRASH] /content-security-policy/meta/sandbox-iframe.html (#43478)
- FAIL [expected PASS] subtest: img-src 'self' works when specified in a meta tag.
```
assert_equals: expected "PASS" but got "FAIL"
```
FAIL [expected PASS] /css/css-backgrounds/background-size-042.html
OK [expected ERROR] /fetch/fetch-later/quota/same-origin-iframe/sandboxed-iframe.https.window.html (#41704)
TIMEOUT /fetch/metadata/generated/css-images.sub.tentative.html (#29047)
- FAIL [expected PASS] subtest: content sec-fetch-site - HTTPS downgrade-upgrade
```
assert_unreached: Reached unreachable code
```
OK /html/browsers/browsing-the-web/navigating-across-documents/navigation-unload-cross-origin.sub.window.html (#29056)
- PASS [expected FAIL] subtest: Cross-origin navigation started from unload handler must be ignored
OK /html/browsers/history/the-history-interface/traverse_the_history_4.html (#21383)
- PASS [expected FAIL] subtest: Multiple history traversals, last would be aborted
OK /html/browsers/history/the-history-interface/traverse_the_history_5.html (#21383)
- PASS [expected FAIL] subtest: Multiple history traversals, last would be aborted

OK /html/browsers/origin/cross-origin-objects/cross-origin-objects.html

FAIL [expected PASS] subtest: Only certain properties are usable as cross-origin this objects (cross-origin)

assert_throws_dom: Should throw when calling window.__wptrunner_testdriver_callback with cross-origin this object function "function() {
    [native code]
}" did not throw

FAIL [expected PASS] subtest: Only certain properties are usable as cross-origin this objects (same-origin + document.domain)

assert_throws_dom: Should throw when calling window.__wptrunner_testdriver_callback with cross-origin this object function "function() {
    [native code]
}" did not throw

OK /html/browsers/windows/embedded-opener-remove-frame.html (#23867)

FAIL [expected PASS] subtest: opener of discarded auxiliary browsing context

assert_object_equals: property "get" expected function "function opener() {
    [native code]
}" got function "function opener() {
    [native code]
}"

OK [expected TIMEOUT] /html/infrastructure/urls/base-url/document-base-url-window-initiator-is-not-opener.https.window.html (#30970)
TIMEOUT [expected OK] /html/interaction/focus/the-autofocus-attribute/autofocus-dialog.html (#29087)
- TIMEOUT [expected FAIL] subtest: <dialog>-contained autofocus element gets focused when the dialog is shown
```
Test timed out
```
OK [expected TIMEOUT] /html/semantics/embedded-content/media-elements/src_object_blob.html (#40340)
- PASS [expected TIMEOUT] subtest: HTMLMediaElement.srcObject blob
CRASH [expected FAIL] /html/semantics/interestfor/interestfor-plain-inline-element.tentative.html
OK /html/semantics/scripting-1/the-script-element/module/dynamic-import/blob-url.any.html (#33948)
- FAIL [expected PASS] subtest: Revoking a blob URL immediately after calling import will not fail
```
promise_test: Unhandled rejection with value: object "TypeError: Module fetching failed"
```
OK /html/semantics/scripting-1/the-script-element/module/dynamic-import/blob-url.any.worker.html (#33909)
- FAIL [expected PASS] subtest: Revoking a blob URL immediately after calling import will not fail
```
promise_test: Unhandled rejection with value: object "TypeError: Module fetching failed"
```

OK /html/webappapis/user-prompts/print-during-unload.html (#35944)

FAIL [expected PASS] subtest: print() during unload

assert_array_equals: expected property 1 to be "destination" but got "error: window.print is not a function" (expected array ["start", "destination"] got ["start", "error: window.print is not a function"])

CRASH [expected OK] /import-maps/csp/unsafe-inline.html
TIMEOUT [expected OK] /pointerevents/compat/pointerevent_touch-action_two-finger_interaction.html (#44693)
- NOTRUN [expected PASS] subtest: touch two-finger pan on 'touch-action: pan-x pan-y'
- NOTRUN [expected FAIL] subtest: touch two-finger pan on 'touch-action: pinch-zoom'
OK [expected TIMEOUT] /trusted-types/trusted-types-navigation.html?06-10 (#37920)
- PASS [expected FAIL] subtest: Navigate a frame via anchor with javascript:-urls in report-only mode.
- PASS [expected TIMEOUT] subtest: Navigate a frame via anchor with javascript:-urls w/ default policy in report-only mode.
- FAIL [expected NOTRUN] subtest: Navigate a window via anchor with javascript:-urls w/ a default policy throwing an exception in enforcing mode.
```
promise_test: Unhandled rejection with value: "Unexpected message received: \"No securitypolicyviolation reported!\""
```
- FAIL [expected NOTRUN] subtest: Navigate a window via anchor with javascript:-urls w/ a default policy throwing an exception in report-only mode.
```
promise_test: Unhandled rejection with value: "Unexpected message received: \"No securitypolicyviolation reported!\""
```
OK /webdriver/tests/classic/element_send_keys/interactability.py
- FAIL [expected PASS] subtest: test_iframe_is_interactable
```
AssertionError: assert 'oo' == 'foo'
```
CRASH [expected OK] /webxr/hit-test/ar_hittest_source_cancel.https.html
CRASH [expected ERROR] /workers/Worker-base64.any.serviceworker.html
CRASH [expected OK] /workers/Worker-multi-port.html
CRASH [expected ERROR] /workers/Worker-replace-self.any.sharedworker.html
CRASH [expected OK] /workers/Worker-terminate-forever-during-evaluation.html
CRASH [expected OK] /workers/Worker-timeout-increasing-order.html
CRASH [expected OK] /workers/WorkerNavigator_userAgentData.http.html
CRASH [expected OK] /workers/Worker_script_mimetype.htm
CRASH [expected OK] /workers/constructors/SharedWorker/global-members.html
CRASH [expected OK] /workers/constructors/SharedWorker/null-arguments.html
CRASH [expected OK] /workers/constructors/SharedWorker/number-arguments.html
CRASH [expected OK] /workers/constructors/SharedWorker/port-properties.html
CRASH [expected OK] /workers/constructors/SharedWorker/setting-port-members.html
CRASH [expected OK] /workers/constructors/SharedWorker/unresolvable-url.html
CRASH [expected OK] /workers/dedicated-worker-parse-error-failure.html
CRASH [expected OK] /workers/examples/general.worker.html
CRASH [expected ERROR] /workers/examples/onconnect.any.sharedworker.html
CRASH [expected OK] /workers/interfaces/DedicatedWorkerGlobalScope/postMessage/event-ports-dedicated.html
CRASH [expected OK] /workers/interfaces/WorkerGlobalScope/onerror/not-handled.html
CRASH [expected OK] /workers/interfaces/WorkerUtils/importScripts/002.worker.html
CRASH [expected OK] /workers/interfaces/WorkerUtils/importScripts/003.html
CRASH [expected OK] /workers/interfaces/WorkerUtils/importScripts/004.html
CRASH [expected ERROR] /workers/interfaces/WorkerUtils/importScripts/report-error-cross-origin.sub.any.sharedworker.html
CRASH [expected OK] /workers/interfaces/WorkerUtils/importScripts/report-error-setTimeout-same-origin.sub.any.worker.html
CRASH [expected OK] /workers/modules/dedicated-worker-import.any.html
CRASH [expected OK] /workers/semantics/encodings/004.worker.html
CRASH [expected OK] /workers/semantics/multiple-workers/003.html
CRASH [expected OK] /workers/shared-worker-from-blob-url.window.html
CRASH [expected OK] /xhr/abort-during-upload.any.html

Stable unexpected results that are known to be intermittent (13)

PASS [expected FAIL] /css/css-fonts/font-feature-settings-descriptor-01.html (#45418)
OK /html/browsers/browsing-the-web/navigating-across-documents/navigation-unload-same-origin-fragment.html (#20768)
- FAIL [expected PASS] subtest: Tests that a fragment navigation in the unload handler will not block the initial navigation
```
assert_equals: expected "" but got "#fragment"
```
OK /html/browsers/browsing-the-web/navigating-across-documents/replace-before-load/a-click.html (#28697)
- PASS [expected FAIL] subtest: aElement.click() before the load event must NOT replace

OK [expected TIMEOUT] /html/browsers/browsing-the-web/navigating-across-documents/replace-before-load/form-requestsubmit.html (#44098)

FAIL [expected TIMEOUT] subtest: Replace before load, triggered by formElement.requestSubmit()

assert_equals: expected "http://web-platform.test:8000/common/blank.html?thereplacement=" but got "http://web-platform.test:8000/html/browsers/browsing-the-web/navigating-across-documents/replace-before-load/resources/code-injector.html?pipe=sub(none)&amp;code=%0A%20%20%20%20const%20form%20%3D%20document.createElement(%22form%22)%3B%0A%20%20%20%20form.action%20%3D%20%22%2Fcommon%2Fblank.html%22%3B%0A%0A%20%20%20%20const%20input%20%3D%20document.createElement(%22input%22)%3B%0A%20%20%20%20input.type%20%3D%20%22hidden%22%3B%0A%20%20%20%20input.name%20%3D%20%22thereplacement%22%3B%0A%20%20%20%20form.append(input)%3B%0A%0A%20%20%20%20document.currentScript.before(form)%3B%0A%20%20%20%20form.requestSubmit()%3B%0A%20%20"

TIMEOUT [expected OK] /html/browsers/browsing-the-web/navigating-across-documents/replace-before-load/form-submit.html (#44028)
OK /html/semantics/scripting-1/the-script-element/module/choice-of-error-1.html (#44058)
- FAIL [expected PASS] subtest: Parse errors in different files should be reported depending on different roots
```
assert_not_equals: two different parse errors should be reported got disallowed value object "SyntaxError: expected expression, got '%'"
```
OK /html/semantics/scripting-1/the-script-element/module/dynamic-import/blob-url.any.worker-module.html (#43510)
- FAIL [expected PASS] subtest: Revoking a blob URL immediately after calling import will not fail
```
promise_test: Unhandled rejection with value: object "TypeError: Module fetching failed"
```
TIMEOUT [expected OK] /html/user-activation/navigation-state-reset-sameorigin.html (#45151)
- TIMEOUT [expected PASS] subtest: Post-navigation state reset.
```
Test timed out
```
OK /navigation-timing/test-navigation-type-reload.html (#33334)
- PASS [expected FAIL] subtest: Reload domComplete > Original domComplete
- PASS [expected FAIL] subtest: Reload domContentLoadedEventEnd > Original domContentLoadedEventEnd
- PASS [expected FAIL] subtest: Reload domContentLoadedEventStart > Original domContentLoadedEventStart
- PASS [expected FAIL] subtest: Reload fetchStart > Original fetchStart
- PASS [expected FAIL] subtest: Reload loadEventEnd > Original loadEventEnd
- PASS [expected FAIL] subtest: Reload loadEventStart > Original loadEventStart
CRASH [expected OK] /resource-timing/render-blocking-status-link.html (#41664)
TIMEOUT [expected OK] /trusted-types/trusted-types-navigation.html?16-20 (#44835)
- TIMEOUT [expected PASS] subtest: Navigate a frame via area with javascript:-urls w/ default policy in enforcing mode.
```
Test timed out
```
- NOTRUN [expected PASS] subtest: Navigate a frame via area with javascript:-urls in report-only mode.
- NOTRUN [expected PASS] subtest: Navigate a frame via area with javascript:-urls w/ default policy in report-only mode.
OK [expected TIMEOUT] /trusted-types/trusted-types-navigation.html?31-35 (#38034)
- PASS [expected TIMEOUT] subtest: Navigate a frame via form-submission with javascript:-urls w/ default policy in report-only mode.
- FAIL [expected NOTRUN] subtest: Navigate a window via form-submission with javascript:-urls w/ a default policy throwing an exception in enforcing mode.
```
promise_test: Unhandled rejection with value: "Unexpected message received: \"No securitypolicyviolation reported!\""
```
- FAIL [expected NOTRUN] subtest: Navigate a window via form-submission with javascript:-urls w/ a default policy throwing an exception in report-only mode.
```
promise_test: Unhandled rejection with value: "Unexpected message received: \"No securitypolicyviolation reported!\""
```
- FAIL [expected NOTRUN] subtest: Navigate a window via form-submission with javascript:-urls w/ a default policy making the URL invalid in enforcing mode.
```
promise_test: Unhandled rejection with value: "Unexpected message received: \"No securitypolicyviolation reported!\""
```
OK /webdriver/tests/classic/accept_alert/accept.py (#43194)
- FAIL [expected PASS] subtest: test_accept_in_popup_window
```
AssertionError: no such alert (404): No user prompt is currently active.
```

github-actions · 2026-06-11T12:59:28Z

✨ Try run (#27345803471) succeeded.

Signed-off-by: Narfinger <Narfinger@users.noreply.github.com>

jdm

Great! The fact that this is statically checked gives me a lot more confidence in reviewing changes like this one.

This implements two new UnrootedIterators (PreceedingNodeIterator and FollowingNodeIterator) with the same schema as the other UnrootedIterators. This also implements using these iterators for HTMLCollections (and their subtypes) and CollectionSource trait as well as a couple of downstream. Special care should be given to check: - The correctness of the new iterators from the point of iterating. - The enum CollectioonKind not having the 'static lifetime anymore. - HTMLFormControlsCollection::NamedItem (which had to be rewritten to make the lifetimes work). - Bugfix in codegen.py to also check the cx._no_gcMethods for Length(cx). - Implementation of PartialEq for UnrootedDom and UnrootedDom<T>==T Most other changes are mechanical &JSContext adding or NoGC propagating. Overall this seems to eliminate rooting overhead on amazon.com down from 1.8% runtime in a small unscientific test. Testing: WPT tests should find any screwups. Signed-off-by: Narfinger <Narfinger@users.noreply.github.com>

Narfinger added the T-linux-wpt Do a try run of the WPT label Jun 11, 2026

Narfinger force-pushed the faster-iterators branch from f5385af to b7d75c3 Compare June 11, 2026 12:13

github-actions Bot removed the T-linux-wpt Do a try run of the WPT label Jun 11, 2026

Narfinger marked this pull request as ready for review June 11, 2026 14:25

Narfinger requested review from gterzian and yezhizhen as code owners June 11, 2026 14:26

servo-highfive added the S-awaiting-review There is new code that needs to be reviewed. label Jun 11, 2026

Narfinger force-pushed the faster-iterators branch from b7d75c3 to b24395b Compare June 12, 2026 08:02

Use unrooted iterators for HTMLCollections

051b359

Signed-off-by: Narfinger <Narfinger@users.noreply.github.com>

Narfinger force-pushed the faster-iterators branch from b24395b to 051b359 Compare June 15, 2026 07:48

jdm approved these changes Jun 16, 2026

View reviewed changes

servo-highfive removed the S-awaiting-review There is new code that needs to be reviewed. label Jun 16, 2026

jdm added this pull request to the merge queue Jun 16, 2026

servo-highfive added the S-awaiting-merge The PR is in the process of compiling and running tests on the automated CI. label Jun 16, 2026

Merged via the queue into servo:main with commit 728e768 Jun 16, 2026
31 checks passed

servo-highfive removed the S-awaiting-merge The PR is in the process of compiling and running tests on the automated CI. label Jun 16, 2026

Narfinger deleted the faster-iterators branch June 17, 2026 13:25

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script: Use unrooted iterators for HTMLCollections - #45582

script: Use unrooted iterators for HTMLCollections#45582
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