test(tree): add tree change event ordering tests by jenn-le · Pull Request #27852 · microsoft/FluidFramework

Jenn (jenn-le) · 2026-08-04T22:30:54Z

Description

Adds tests that assert the ordering guarantees of SharedTree's change events (nodeChanged, treeChanged, rootChanged) and their interaction with withBufferedTreeEvents. These tests document and lock in the following behaviors:

nodeChanged fires before treeChanged on the same node
Events propagate bottom-up through the tree hierarchy
rootChanged fires after nodeChanged/treeChanged (via afterBatch)
withBufferedTreeEvents inverts rootChanged relative to buffered node events
Node events respect ordering within buffered flushes

Also updates a TODO comment in treeChangeEvents.ts to document the confirmed bottom-up ordering behavior.

Reviewer Guidance

Reviewer Guidance Wiki

The test file is self-contained. The only production code change is replacing a TODO with documentation (line 69 of treeChangeEvents.ts).

github-actions · 2026-08-04T22:31:55Z

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github-actions · 2026-08-07T01:10:31Z

🔗 No broken links found! ✅

Your attention to detail is admirable.

linkcheck output

1: starting server using command "npm run serve -- --no-open"
and when url "[ 'http://127.0.0.1:3000' ]" is responding with HTTP status code 200
running tests using command "npm run check-links"


> fluid-framework-website@0.0.0 serve
> docusaurus serve --no-open

[SUCCESS] Serving "build" directory at: http://localhost:3000/

> fluid-framework-website@0.0.0 check-links
> linkcheck http://localhost:3000 --skip-file skipped-urls.txt

Crawling...

Stats:
  309092 links
    1963 destination URLs
    2219 URLs ignored
       0 warnings
       0 errors

Joshua Smithrud (Josmithr) · 2026-08-07T17:45:36Z

Jenn (@jenn-le) Looks like this PR has some extraneous changes FYI

Add a new test file (treeChangeEventOrdering.spec.ts) that validates the ordering guarantees of nodeChanged, treeChanged, and rootChanged events: - Single node: nodeChanged fires before treeChanged on the same node - Parent+child: bottom-up ordering with nodeChanged before treeChanged at each level, tested with 2-level and 3-level hierarchies - rootChanged: fires after nodeChanged/treeChanged (afterBatch listener) - withBufferedTreeEvents: documents that rootChanged fires during the callback (not buffered by KernelEventBuffer) while node events are buffered and flushed after, inverting the normal ordering - Buffered events preserve nodeChanged-before-treeChanged on flush Also replaces the TODO comment in treeChangeEvents.ts with documentation of the bottom-up event ordering behavior. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Factor the repeated TreeBeta.on(node, 'nodeChanged'/treeChanged', ...) pattern into a subscribeToNodeEvents(node, log, prefix?) helper function, reducing boilerplate across all test cases. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

…d test Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

…adability Replace index-based and loop-based assertions with direct deepEqual comparisons of the full expected event log. This makes the expected ordering immediately visible while also being future-proof — any unexpected extra or reordered events will cause a clear failure. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

daesunp · 2026-08-10T20:21:29Z

+			// Both parent and child change in the same buffered batch
+			withBufferedTreeEvents(() => {
+				root.child.value = 42;
+				root.ownProp = "world";


I tried running this test with the edit order switched, and the test failed, so we may have to find a different way to test this (which I don't know either). I chatted with Craig about this a while ago, so I think he may have some good ideas on how to test this

Actually I made a mistake, it still orders nodeChanged before treeChanged, so this test is good :)

I added another test and clarified some docs showing that the event order is based on edit order but nodeChanged comes before treeChanged for each node

When both parent and child are directly edited in a buffered batch, events fire in the order nodes were first edited — not strictly bottom-up by tree depth. Updates the doc comment in treeChangeEvents.ts to reflect this more accurate description. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

github-actions · 2026-08-11T01:05:50Z

Bundle size comparison

Base commit: 7c161bef46c3679c2b494a6798616f5a9d1bf25e
Head commit: cf3ecb904d459bdeb9deef8abdc84ab63e0660d7

Notable changes

No bundles changed by ≥ 500 bytes parsed.

Per-bundle deltas

`@fluid-example/bundle-size-tests`

fluidFrameworkAllAlpha.js: parsed 780911 → 780953 (+42), gzip 214191 → 214228 (+37)
azureClient.js: parsed 624465 → 624521 (+56), gzip 166500 → 166545 (+45)
odspClient.js: parsed 596753 → 596809 (+56), gzip 159641 → 159685 (+44)
aqueduct.js: parsed 530843 → 530878 (+35), gzip 141979 → 142008 (+29)
fluidFramework.js: parsed 399466 → 399487 (+21), gzip 113434 → 113450 (+16)
sharedTree.js: parsed 388870 → 388884 (+14), gzip 110880 → 110889 (+9)
containerRuntime.js: parsed 308960 → 308974 (+14), gzip 84482 → 84488 (+6)
sharedString.js: parsed 176457 → 176464 (+7), gzip 49807 → 49815 (+8)
experimentalSharedTree.js: parsed 160677 → 160677 (0), gzip 46276 → 46276 (0)
matrix.js: parsed 160302 → 160309 (+7), gzip 45800 → 45807 (+7)
loader.js: parsed 145700 → 145714 (+14), gzip 39284 → 39300 (+16)
odspDriver.js: parsed 103906 → 103927 (+21), gzip 32404 → 32411 (+7)
directory.js: parsed 67110 → 67117 (+7), gzip 18859 → 18866 (+7)
578.js: parsed 58686 → 58686 (0), gzip 17657 → 17657 (0)
map.js: parsed 47205 → 47212 (+7), gzip 14455 → 14462 (+7)
odspPrefetchSnapshot.js: parsed 45635 → 45649 (+14), gzip 15242 → 15250 (+8)
252.js: parsed 44371 → 44371 (0), gzip 13732 → 13732 (0)
summarizerDelayLoadedModule.js: parsed 30717 → 30717 (0), gzip 7716 → 7716 (0)
socketModule.js: parsed 26469 → 26476 (+7), gzip 7896 → 7904 (+8)
createNewModule.js: parsed 12454 → 12454 (0), gzip 4797 → 4797 (0)
summaryModule.js: parsed 3789 → 3789 (0), gzip 1857 → 1857 (0)
connectionState.js: parsed 909 → 909 (0), gzip 500 → 500 (0)
sharedTreeAttributes.js: parsed 847 → 854 (+7), gzip 499 → 508 (+9)
debugAssert.js: parsed 429 → 429 (0), gzip 299 → 299 (0)
FluidFramework-HashFallback.js: parsed 419 → 419 (0), gzip 313 → 313 (0)

Copilot AI lite review requested due to automatic review settings August 4, 2026 22:30

Jenn (jenn-le) requested a review from a team as a code owner August 4, 2026 22:30

github-actions Bot added area: tools area: dds Issues related to distributed data structures area: repo Repo related work area: website area: dds: tree base: main PRs targeted against main branch labels Aug 4, 2026

Copilot started reviewing on behalf of Jenn (jenn-le) August 4, 2026 22:31 View session

Copilot AI reviewed Aug 4, 2026

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Jenn (jenn-le) changed the title ~~test(tree): add comprehensive tree change event ordering tests~~ test(tree): add tree change event ordering tests Aug 4, 2026

Jenn (jenn-le) requested a review from a team as a code owner August 7, 2026 01:01

Jenn (jenn-le) and others added 4 commits August 10, 2026 11:33

Refactor: use deepEqual for concrete expected ordering in parent+chil…

330e751

…d test Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Jenn (jenn-le) force-pushed the jenn-le-tree-event-ordering-tests branch from fc55d51 to 7eb201d Compare August 10, 2026 18:34

github-actions Bot removed the area: examples Changes that focus on our examples label Aug 10, 2026

daesunp reviewed Aug 10, 2026

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daesunp approved these changes Aug 10, 2026

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Simplify comments in edit-order test

dbb117c

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

daesunp approved these changes Aug 10, 2026

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Jenn (jenn-le) enabled auto-merge (squash) August 10, 2026 22:21

Fix indentation in event ordering test

cf3ecb9

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

daesunp approved these changes Aug 11, 2026

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Jenn (jenn-le) merged commit 086df40 into microsoft:main Aug 11, 2026
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test(tree): add tree change event ordering tests - #27852

test(tree): add tree change event ordering tests#27852
Jenn (jenn-le) merged 7 commits into
microsoft:mainfrom
jenn-le:jenn-le-tree-event-ordering-tests

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Jenn (jenn-le) commented Aug 4, 2026

Description

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linkcheck output

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Bundle size comparison

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@fluid-example/bundle-size-tests

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github-actions Bot commented Aug 4, 2026 •

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