A near-uniform drag collapses to the `scale` shorthand, but the finalize step
measured the element at the per-axis pair it computed rather than the single
value the commit writes. The element was measured at a scaleY the file never
gets, so the position correction came out tilted by the difference.
Adds a sweep over the shapes a composition produces — shrink, grow, first
resize, rotated, steeply rotated, non-uniform, near-zero, inline-sized, no
position write, animated position, and two drags in a row — each checking the
element renders on its drop point from the PERSISTED scale and position. The
geometry model is calibrated against real gesture traces: the same inputs
reproduce the rects the browser reported to three decimals.
A scale resize measured its drop-point correction while the gesture's own
translation was still applied, but the position commit adds that correction
onto the element's PRE-gesture position, which it reads from the gesture's
base attributes. The two disagreed by the whole drag distance, so the commit
persisted a position a drag-length from where the element was dropped: it
held the drop point for one frame and then slid off.
Move the element back to that base before measuring, so the residual and the
commit share one origin. For an element whose position is a static hold that
usually means no correction at all, which is the right answer: scaling about
the centre already leaves it on the drop point.
An element whose position is animated left the drop point anyway. The
finalize step wrote its correction as a static position hold, and the
element's position tween rendered its own value a frame later and won.
Before that it stood down entirely on such elements, on the grounds that
a keyframed path has no single anchor to preserve, which had the same
visible result: the element moved.
It has an anchor, the frame the user is looking at. The correction now
goes into that tween at the playhead, through commitGsapPositionFromDrag,
which is the same commit a drag on the same element already uses. Static
holds keep the existing path.
This is the difference the debug log showed between an element carrying
position:to, which moved after release, and one carrying position:set,
which did not.
The finalize step measures where the committed scale put the box and
shifts the position hold by the difference. Whether the commit had
actually rendered when it measured was luck: on a first resize the
timeline had not re-seeked, so it measured the element at its natural
size still sitting on the drop point, saw no residual, and skipped the
correction. The scale then landed, GSAP rendered it about the element's
centre, and the element jumped by the whole drag distance. Elements
resized before got a correction only because their previous scale made
the residual non-zero by accident.
The committed scale is now applied to the live element before measuring,
so the measurement means what its comment says either way, and a skipped
correction is logged rather than silent.
Confirmed against a real session: a first resize of a 630px chip now
reports residual -109.93 and lands on the drop point, where it previously
logged no scale-finalize at all.
A uniform drag committed the `scale` shorthand. If the tween's keyframes
already stated `scaleX` and `scaleY`, the commit left both forms in the
same keyframe, and GSAP animates each property name independently, so the
longhands ran alongside the shorthand and won.
The resize therefore computed the right number, wrote it to the file, and
did nothing: the element snapped back to its old size the moment the
handle was released. Reproduced from a real session, where a drop at 384px
on a 630px element wrote {scaleX: 1, scaleY: 1, scale: 0.61} and rendered
at the original size.
The mixing hazard was already known in the other direction, where a
non-uniform drag takes a rewrite path that normalizes every keyframe to
the longhands. This makes the condition symmetric: whenever the tween
already speaks longhands, a uniform drag speaks them too.
Resizing an element whose size is driven by a scale animation committed a
scale computed against a hardcoded 200px fallback, because the only
original size the draft recorded was the element's INLINE width, and a
composition sizes its elements from the stylesheet.
A 630px chip dropped at 1260px wide committed a scale of 6.3 instead of 2,
so it landed at over three times the size it was dropped at. The next drag
compounded it, because that wrong scale then counted as the element's live
one.
The draft now records the box it measured, once, before it writes a width
of its own, and the intercept reads that. The inline attributes keep their
own job of restoring an inline style, which is why they cannot answer this
question.
Review caught that the same anti-pattern was still live in the Studio binding:
canaryEventProperties destructured only `enabled` and dropped the reason. Its
own doc comment promised 'identical shape to the CLI, so a rollout spanning
both reads as one flag' — which the CLI-only fix had just made false.
This matters beyond symmetry. A CLI-launched Studio adopts the CLI's decisions
and shares its bucket seed, so a cohort flip can surface on either surface.
Emitting attribution on only one leaves Studio-observed flips unattributable
and makes the two flip counts irreconcilable — and Studio is the surface most
likely to expose a shared-seed-with-diverging-id pattern, which is the open
question the reason exists to answer.
Also adds the no_unit_id emission test the CLI side advertised but never
asserted, and a Studio pair pinning that a URL override and a cohort roll
produce the same assignment with different reasons.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
- A long-lived preview cached its telemetry posture in two places
(readConfig and shouldTrack). Running `telemetry disable` in another
terminal left it resolving canaries and injecting the CLI id for hours.
Both caches are now dropped together at a request boundary.
- Studio minted and shipped a telemetry id for every render regardless of
the browser profile's opt-out, and the server emitted the outcome under
CLI policy, which cannot see localStorage or DNT. The browser now sends
an explicit telemetryOptOut, distinct from an old client's omission.
- Any non-empty HYPERFRAMES_PREVIEW_HOST disabled the DNS-rebinding guard,
so even a loopback bind accepted a hostile Host. The guard now holds for
loopback binds and, on a LAN bind, admits only names this machine
answers on.
- sunsetAfter had no reader of the current date. A scheduled workflow runs
scripts/check-canary-sunset.ts weekly, so a failure lands on the
rollout's owner rather than on an unrelated PR author.
- The install-state seed memo outlived `rm -rf ~/.hyperframes`,
resurrecting a cleared cohort. Removed; it only saved a read on a
readConfig cache miss.
Docs updated for the Host rule and the 100% exclusion carve-out.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
* perf(studio): define timeline viewport budgets and fixtures
* test(studio): gate timeline viewport performance in Chromium
* refactor(studio): isolate clip drag lifecycle
* refactor(studio): extract timeline render contracts
* perf(studio): centralize timeline viewport geometry
* perf(studio): follow playhead across virtualized rows
* perf(studio): add timeline clip-window index primitive
* perf(studio): virtualize timeline clip windows
* perf(studio): stop timeline scroll work when row virtualization is off
The row virtualization stack made the timeline publish a viewport snapshot
on every scroll frame and swap `renderClipContent` across every mounted clip
at gesture start and settle. Both are windowing concessions, and neither was
gated on the flag, so the build users actually run paid for them while
mounting all 1,000 clips anyway. Measured on a 3,000-clip project: median
scroll step 16.6ms to 76.9ms, p95 17.9ms to 189.4ms, 40 long tasks to 247.
Gate both on the row virtualization flag. The scroll path now stops at the
door when the flag is off, so `isScrolling` stays false and resize-driven
and programmatic syncs still publish through the immediate path.
The flag moves into its own module: the scroll-viewport hook needs to read
it, and the virtualization hook already imports the viewport snapshot type
back, which would have closed an import cycle.
Also release the perf fixture lease from the fixture rather than from the
test-hook effect. Loading a fixture writes player state, which changed that
effect's dependency identities and tore it down on the next frame, so the
lease was revoked moments after it was taken and live iframe discovery
overwrote the fixture before the gate could measure it.
The e2e gate gains a flag-off arm (`test:timeline-default`, 1,000 elements)
next to the existing flag-on one. It refuses the 50,000-element combination,
verifies from the mounted DOM that the server under test matches the
requested flag, and skips the DOM-size budgets for the unvirtualized build
rather than relaxing them, so a skipped budget never reads as a passed one.
Verified against a live Studio dev server on the fixture project:
flag off, before: interactionP95 303.1ms, longest task 194ms, 0/5 runs pass
flag off, after: interactionP95 33.6ms, longest task 0ms, 5/5 runs pass
flag on, after: interactionP95 33.2ms, 4/5 runs pass, exit 0
The flag-on arm's fourth run reproducibly reports a 55-58ms long task
against a 50ms budget. That is the residual tail of the window swap itself,
tracked separately and not addressed here.
* ci(studio): run the timeline viewport gate on studio changes
The gate has existed since the row virtualization stack landed but nothing
under `.github/` referenced it, so it only ever ran when someone ran it by
hand. That is how the flag-off scroll regression reached eight merged-ready
PRs without anything noticing.
Adds a `studio-timeline-viewport` job that boots two Studio dev servers, one
per flag state, and runs both arms of the gate against them. Two servers are
needed because row virtualization is read from `import.meta.env` at module
load, so one process cannot serve both builds.
Scoped to a new `studio` paths filter rather than the broad `code` one: the
gate only says anything about `packages/studio`, `packages/core` and
`packages/studio-server`.
Adds a `ci` tier. It applies the constrained budgets without any emulation,
because a hosted runner is already slower and noisier than the machine the
strict numbers were recorded on, while the existing `low-resource` tier would
throttle it a further 4x and measure the throttle rather than the build.
The fixture composition is tracked under `tests/e2e/fixtures` but Studio
resolves projects from the gitignored `data/projects`, so the job copies it
into place instead of a project directory being committed.
Both arms run in about 7 seconds each locally, so the job cost is almost
entirely dependency install and the workspace build it shares with
`studio-load-smoke`.
* fix(ci): preserve both timeline gate evidence arms
* ci(studio): report timeline gate arm statuses
* ci(studio): require timeline gate evidence artifacts
* fix(studio): keep dense keyframes readable
* fix(ci): resolve timeline stack audit findings
R5 blockers
- Negative install-state latch was cached for the process lifetime, but
only `true` is monotonic across processes. A long-lived preview server
held a stale `false` and could re-enrol after another process tripped
the breaker. Only the positive is cached now; `false` re-reads.
- The real breaker writer used writeConfig(), which collapses
{ok:true, mirrored:false} to success, so a run that mirrored nothing
reported done with the latch only on the erasable store. It consumes
writeConfigWithResult and retries until both stores carry it.
Bucketing integrity
- Storage-restricted Studio profiles all bucketed on the literal
"anonymous": computed against the shipped hash, 100% of them were
enrolled in calibration-50 rather than 50%, and they merged into one
PostHog person. Per-session random id instead — persists nothing.
- bucketSeed had read/write authority backwards: install-state is
write-once authoritative, but readConfig took config.json's blindly, so
the stores could hold different seeds until a re-mint flipped every
cohort. Merged on read, like the latch.
- An unwritable ~/.hyperframes with no config.json re-minted per call,
re-rolling the seed on every command, and the "cohorts will not be
stable" warning was unreachable on that path.
- A corrupt PRE-MOVE state file was never deleted, so a machine reset
with `rm -rf ~/.hyperframes` reported predecessorFound/stateFileCorrupt
forever — poisoning the exact metric this work exists to produce.
Opt-out honoring
- CLI canary decisions memoized per process, so `hyperframes telemetry
disable` during a running preview server was ignored for hours while
the server kept serving pre-opt-out decisions. The memo is keyed on the
telemetry posture.
- shouldTrack() memoized, contradicting policy.ts's documented "not
memoized" contract that policy.test.ts asserts.
- The Studio override path resolved the bucket unit eagerly as an
argument, minting and PERSISTING a tracking id for an opted-out profile
— a value evaluateCanary discards unread.
- Storage reads could throw out of telemetry into a post-commit catch
block, reporting an already-committed edit as failed.
- readConfig printed an unsilenceable stderr warning on every invocation
for installs that opted out of telemetry entirely.
Host split
- isLoopbackHost rejected 0.0.0.0, so the documented
HYPERFRAMES_PREVIEW_HOST LAN mode silently lost CLI→Studio identity
stitching and split one user across two PostHog persons. Identity is
now allowed when the operator explicitly opted into LAN binding.
- Corrected the comment claiming the guard refuses spoofed Hosts: a
non-browser client sets Host freely. It is a browser DNS-rebinding
mitigation, not access control, and now says so.
Semantics and test hygiene
- percentage:100 did not mean everyone — exclude and no_unit_id sat above
the fast path, so the registry's "delete the entry at 100" step was an
unstaged flip for CI and seedless installs.
- CLI cohort adoption returned before evaluateCanary, dropping Studio's
own webdriver exclusion.
- overdueCanaries() was asserted against wall-clock time, so the whole
core suite would go red on 2026-09-15 for every unrelated PR; and `>`
against midnight made a canary overdue ON its sunset date.
- Statistical assertions ran on unseeded randomUUID() populations tight
enough to fail ~1 run in 200. Seeded.
Also: broke a config -> policy -> transport -> config import cycle by
moving POSTHOG_API_KEY to a leaf module.
Tests: 2347 CLI (bundle absent), 3153 Studio, 1450 core. Fault injection
covers the latch, seed authority, LAN identity, webdriver exclusion and
the anonymous-bucket fix. Two pre-existing tests asserted behaviour these
findings identify as wrong (shouldTrack memoization, 100%-excludes-CI)
and were rewritten with the reasoning stated.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
P1 — the required Test lane was red, and it was my test. The
hostile-Host SPA case asserted a 200, which only holds when
packages/studio/dist is built: true on a dev box, false in CI, so it
passed locally and failed there. The Host split moved into a pure
buildStudioHeadScriptsForHost() and is asserted directly; the route test
no longer depends on build state. Verified by running the CLI suite with
the bundle moved aside — 2330 pass.
P1 — studio:* still bypassed most privacy controls. It honoured two
localStorage keys but not navigator.doNotTrack,
VITE_HYPERFRAMES_NO_TELEMETRY, Vite dev mode or API-key eligibility, and
canary enrolment honoured a different single control. New
telemetry/policy.ts is the one answer to "may this profile be measured",
consumed by both transports and by enrolment. It imports only ./config,
so no cycle with the modules that import it. Each control is asserted
individually.
P1 — LAN/remote preview lost the authoritative decisions. Withholding
the whole head script for any non-loopback Host also dropped the safe
{enabled, forced} map, sending a supported HYPERFRAMES_PREVIEW_HOST=
0.0.0.0 Studio back to re-deriving. Identity injection is now gated
separately from decision injection: identity is loopback-only, decisions
always publish.
P1 — the breaker latch was neither authoritative nor truthfully
persisted. syncInstallState swallowed its own failures so
writeConfigWithResult always reported ok, and reads took the flag only
from config.json. The latch is now merged into every effective read,
which makes install-state authoritative and closes both the failed-mirror
and stale-concurrent-writer paths; the write additionally reports
mirrored: false rather than swallowing.
P2 — public contracts. canary-rollouts.mdx said a config wipe loses the
breaker (it does not) and documented the superseded {name: boolean} map
with unconditional CLI precedence; both corrected, with the precedence
ladder written out and the override exception stated explicitly. PR body
rewritten — it still named ~/.local/state, claimed state survives
deleting ~/.hyperframes, and carried stale counts.
Tests: 2330 CLI (bundle absent), 3151 Studio, 24 core. Fault injection:
reverting each fix alone fails 5 CLI / 5 Studio.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Miguel Ángel