Trendlines project into the whitespace beyond the newest candle, but the time
axis stopped there, so a converging pair could be seen without knowing when it
converges. Lightweight Charts only labels times present on its scale, so the
chart now carries whitespace points past the last bar: no value, nothing drawn,
but the axis has something to label and timeToCoordinate answers out there.
Future times repeat the most recent bar interval, which is what timeAtIndex
already does for the projections themselves. That drifts across the daily halt
and the weekend; agreeing with the projected line matters more than abstract
accuracy, and session-accurate projection needs server-side session rules the
client does not have.
Two bugs surfaced while measuring it. Padding meant to be five bars measured as
sixty-seven, because the interval came from the gap between the final two bars;
barInterval now takes a median over recent bars and ignores a ragged tail.
And that gap was two seconds on a one-minute chart because Yahoo stamps its
in-progress candle with the time of the request, while the poller emitted
anything newer than the last thing it sent. Every poll therefore appended a new
"1m" bar seconds after the previous one, interleaved with the real ones — live
in production, which is still on Yahoo. Timestamps are bucketed on parse, and
the final candle is emitted unclosed so it revises the current minute rather
than entering the aggregator and adding its volume to every higher timeframe
again on each poll. Verified live: eight consecutive bars, all aligned, all
sixty seconds apart.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
P0 from docs/async_refactor.md. The mutating routes are sync `def`, so FastAPI
runs them in a threadpool, and they reach Runtime.broadcast through
rebuild_levels — writing asyncio.Queue directly from there. That queue is not
thread-safe: it wakes a consumer by resolving a Future, which only the loop
thread may do. A dropped wakeup means a drawing made in one browser does not
reach another until the next market tick.
broadcast now posts through call_soon_threadsafe when it is off the loop, and
publishes directly when it is on it, so the stream's own path pays nothing.
Worth being straight about the tests: the race is timing-dependent and did not
reproduce in twenty attempts — a foreign-thread put_nowait usually lands in the
ready queue before the loop sleeps, and a tick every second covers the rest.
Even asyncio's debug thread-affinity check stays quiet unless a consumer is
parked on the Future at that instant. So the tests assert the contract rather
than provoke the failure: a broadcast from a worker thread must go through
call_soon_threadsafe, one from the loop must deliver synchronously, and both
must arrive.
Also adds the loop-lag probe, which reports scheduling drift as loop_lag_ms on
/api/status. It found P1 on its first run: 19,441ms worst against 1.5ms in
steady state, which is seeding blocking the loop. "The chart feels laggy" is now
a number.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
- Duplicate and delete from the line context menu.
- Copies shift ten bars right.
- Default names are up and down; copies become up 2, down 2, etc.
- Exact local data receipt time including seconds.
- Deployment timestamp removed.
- Test cleanup no longer deletes drawings created from your browser.
- JWT password session flow.
The trendline snap indicator was 66 pixels out, and so was every other overlay.
Lightweight Charts reports coordinates from the plot area's origin. The chart
element also contains the price scales, so enabling the left scale for the daily
labels moved the plot 66px into the element — and each overlay positioned with
left: against the element inherited that error twice over. The cursor's
element-x was read as a plot-x, resolving a bar about 66px right of the pointer;
the indicator was then drawn at that bar's plot-x interpreted as element-x,
landing 66px left of where the bar is painted. Neither near the cursor nor near
the bar, and scaling with zoom — two bars at 30m, a dozen at 1m — which is why
it read as random rather than as an offset.
Every diagnostic number agreed with itself the whole time, because dot_y,
expected_y and bar_low_y all come from the same API and shared the same wrong
origin. Instrumentation cannot see a systematic error in its own frame of
reference; what found this was comparing canvas.width to element.clientWidth and
getting 0.894.
Overlays now live in one container positioned over the plot canvas and inherit
plot coordinates untranslated — snap dot and label, comments, anchor handles,
preview line, tooltip, price tag, context menu — and eventPoint subtracts the
same offset so a pointer position and a chart coordinate mean the same thing.
The container follows the plot on resize.
Verified in page pixels rather than through the coordinate API: with the cursor
placed 30px below a known bar's low, the dot lands 30px above the cursor, on
that low, labelled 7789.00 L against a bar low of 7789.
Device pixel ratio, viewport size, resize desynchronisation and the chart
scrolling under the gesture were each measured and ruled out before this. The
e2e helper computed expected times from element-relative x, the same mistake in
the tests, and is corrected here.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
