A row of `photos` kept the frame's own FileSystemFileHandle, and reading the
catalogue handed them all to the page at once. Measured on a catalogue of
504290 frames, 458103 of them with a handle, opening the library left the JS
heap at 133MB while the browser process held 5.7GB and the renderer 2.1GB:
handles are not the page's heap, so nothing ever asked the collector to run,
and the rescan's own reload of the catalogue every thirty seconds piled one
such reading on the next until the tab was out of memory.
No row keeps a handle now. The catalogue is read a few thousand rows at a time
— the four and a half gigabytes of live handles came from asking for all of
them at once — and a frame's file is asked of its folder's handle when it is
drawn or opened, `fileHandleFor`. `reconnectPhotosForFolders` no longer writes
handles back into the frames, which is what put them there.
504290 rows read in chunks peak at 1.4GB and settle at 1.1GB, against 8.0GB in
one read before.
`saveWalkedDirs` filled in a nought beside every folder a reading had listed but
never opened. A reading stopped by a closed tab, and one kept to a branch, list
the rest of the roll before they have been into any of it — 484 folders of one
real roll read empty over tens of thousands of frames — and the record is folded
back into itself, so the noughts stayed.
Only a reading that met the whole roll may say nought now (`WalkedDirs.full`), and
the screen drops a nought from a record that does not say so. An old record has no
word to give, so its rows fall back on the catalogue instead.
feat(library): search Immich from the filter row
One box, one query, one node: the backend reads what is typed as a tag name when
the key can see one and as a file name otherwise, and the answer is filed under the
node itself. A share link searches its one album in place. The box is not a filter —
it leaves the shelf, which is what the md's search permission is for.
feat(ui): a shorter status line, and a wall that keeps its own row height
The status line is one short 12px row at the foot of the library. A wall with fewer
frames than there are columns no longer stretches its one row — and the cards' own
borders with it — down to the stage.
- boundary: src/ui/ErrorBoundary.tsx, around the whole app rather than around a
screen. A throw on the way to the first paint used to be a white page with
nothing in it to report; it is a sentence, the message and the stack now, with
a reload beside them, so the next report of a crash carries what went wrong.
- one window: src/ui/SingleTab.tsx holds the app to one tab over localStorage and
a BroadcastChannel. A second tab on /app or /library is told so and offered the
roll — "use this tab" takes it, and the tab that held it gets a bar and the
offer back. A tab holding a reading is a tab the machine has already spent its
memory on, and a second one beside it is the memory the first will not get.
- mount: the studio and the library are mounted the first time their route is
asked for and stay mounted after that, not on every visit. Booting CanvasKit
(~20MB) and reading the whole catalogue on a page that shows neither is the
read and the memory a machine short of either takes for a crash; a trip back
from the studio is a screen opening rather than a page loading.
- reading: READ_MS bounds one touch of the disk at 30s. getFile and arrayBuffer
on a drive that has gone away do not fail, they never settle — the lane waits
for ever, the reading never ends, and STOP is a button with nothing left to
read it. A frame given up on is a frame the next reading takes up again.
- reading: the rows of a walk go down a pass at a time, so a tab that never comes
back leaves the column with the folders this reading walked rather than the ones
the last reading did.
- reading: a stopped reading hands over the numbers it counted instead of null.
Handed null it threw its own count away and had noughts written for every folder
it walked that the file did not already hold, so a folder added to a drive read
nought until the next scan.
- repair: STOP ends the afternoon. A repair is a loop the button has no handle on,
so it holds the count of stops it started at and compares between rolls, and
says it was cut short rather than reporting a run it did not make.
- add: a folder the browser could not name — every drive root on Windows is "\" —
is asked for one, and a folder whose name is already another folder's is refused
rather than folded in with it. The record, the frame ids, the walk's position
and the number the column draws are all keyed by that name.
- wall: four hundred tiles queued ahead is a reader waiting on frames three
screens below the one they are looking at; sixty is a screenful and the wall
mints the rest as it scrolls. The catalogue is read back every 30s, not every
5s — reading it back costs every thumbnail in it.
- library: the note is drawn under the frame rather than above it. A line that
comes and goes in the flow moved the frame, the column and the strip by its own
height every time a scan started or ended.
- manifest: "id": "/", so the installed app and the tab are one app.
- checks: tree-scan-check waited for a count of exactly four rows — a state the
screen does not have. The wait ran out its clock and then measured whatever the
reading had done since; it waits for the whole tree now.
A deployment no longer suggests an address for the first server: every
address is each account's own and is typed in the app, so the field opens
blank with a placeholder. The env var, its compose passthrough, the example
line and the `defaultUrl` field that carried it are all gone; the backend's
config route now answers with the saved list alone.
Adding a server no longer opens with a tick list: a fresh node keeps every
album its key can see — the empty album list the backend stores for "all of
them" — and narrowing is a change made on the node that is already there.
The album-ID field carries the warnings that were silent before it: a line
with no id in it, and an id this key never named, both said where they are
typed. A node's key can now be replaced in the dialog that narrows its
albums; the backend probes it first, so a key that does not answer leaves
the node and the dialog as they were.
A saved Immich server is a node on the column beside the drives: no handle,
no picker — the key lives on the backend and the page only ever calls
`/api/immich/*` on its own origin. The dialog takes the address, the name and
the key, checks the key before storing anything, and offers the albums the key
can see; a blank tick list and a blank id field both mean every album. A share
key is one album and so has no picker.
`syncImmich` turns a server's albums into the shapes the tree already draws —
rows in `photos`, names in `walked` — so the column, the wall and the strip
need nothing new. The node's menu is the disk's menu minus what a server has
no disk for.
Also fixes `saveWalkedDirs` filling its noughts in before folding the keys:
a reading that spelled its keys the way it found them (a server's album
labels) had the lower-case spelling of a counted key written in as nought,
and the fold that settles the two spellings kept the nought.
Switching from ALL THUMBS to SINGLE opened the frame nearest the middle of
the wall, not the one that was pressed, and the strip then centred that
stranger. `openFromWall` now prefers the last frame the reader chose when it
is still in the listed shelf, and falls back to the nearest card as before.
A frame the studio graded kept its look in the tile but the stage was read
from the file, so the preview showed the negative the tile was made from.
`stageSrc` now draws the graded tile, and the `onThumbWritten` subscription
marks the frame edited so the shelf is current when the reader comes back.
Verified: scripts/wall-check.mjs, and the D22 harness against the deployed
build on 8090 (all ok, stage vs tile diff 0.0).
Choosing another row in the column read the whole roll back out of the store and asked it for a tile of every frame in one transaction: 20 000 requests in flight at once at 40 000 frames, a 200 ms block of the main thread per switch, and a mint job over the whole folder. The rows are the ones the screen is holding already, the store is asked a chunk at a time, and a folder opening under the pointer is the head of the list — the wall mints the rest as it scrolls. MAKE THUMBS by hand still walks the whole folder.
A column count read back off the cards the window drew is an input the window
feeds itself with: the drawn run is a whole number of rows, and those rows were
read back into the count. A wall hidden behind the studio read nothing but zeroes
off its own cards and reset itself to the top on the way out. Either way a window
was written from a window, pass after pass, until React gave up with #185 and the
whole screen went white — there is nothing between that throw and the floor.
The count now comes off the grid, which is the same read the settle effect above
already scrolls the wall by; a wall with no box is not measured at all, and is
measured on the frame it comes back up; the one reset is written off the shelf's
own length rather than off the last window; the scroller is not a place the
browser may anchor; and a chain of writes past four is cut until something
outside moves — a scroll, a resize, or another shelf.
Selecting thumbs or flipping SINGLE <-> ALL THUMBS on a roll whose captions wrap
to different heights crashed the shelf with React #185 ("Maximum update depth
exceeded") and left the screen blank. useWallWindow read the step from one row to
the next off the rows the window itself had drawn, and the average of a run of
rows moves as the run grows: `to` traded places with a sum a row away — 35, 40,
35, 40, three milliseconds apart — every pass a render, until React gave up.
The step is taken once per column count and kept, re-read when the wall
re-columns, which is the only thing that changes a card own height (a caption
wraps at the width it is given). The window is a function of the scroll and
nothing else, so it settles.
Reproduced with the storm probe against a 3000-frame roll of unevenly named
frames: before, blank at round 1 with #185; after, 12 rounds of hard
SINGLE/ALL THUMBS toggling plus a round trip through the studio — no error, no
blank screen, and D18 unchanged (tile CHANGED, the shelf raising the studio
frame 4px off centre, the studio link opening the same frame).
- tiles land one at a time. The screenful a picked folder asks for was built all
at once, and a HEIC or a RAW in it is a decode of its own, so the strip stood
empty until every one of them was done: 2293ms on a roll of eighteen, with the
batch arriving in one go (0/18 then 18/18 in a single step). Tiles are built in
two lanes now and each one goes up the moment it is drawn — first picture at
36ms, then 1, 2, 4, 6, 8, 9, 11, 12, 14, 15, 16, 17, 18 of 18, done at 2496ms.
The threading is handed back between tiles (`scheduler.yield`), so a click
still answers while the strip fills: no long tasks either side, worst frame gap
169ms -> 164ms, a view toggle 49ms -> 41ms. The tiles are the same tiles; the
wall's is drawn from the same counter.
- the studio's look reaches the shelf. A frame graded in the studio writes the
tile the shelf draws, at neutral geometry — no turn, crop, watermark or frame,
since the shelf turns a tile itself — and every screen holding the tile is told
the moment it is written, so the row repaints without a reload.
- the shelf comes back on the frame the studio was holding. The frame a visit
opened is kept with the visit, and coming back from the studio raises it: the
strip centres it and the wall brings its card to the middle, even when the
frame sits in another folder of the same tree. A shelf that opened on whatever
it was left standing on sent the reader looking for the frame they had just
been working on.
- the frame's name stands under the picture, in the studio's own meta bar.
Settings changed in the studio were remembered per photo, but only as a
film recipe, so everything outside that recipe (straighten, flips, crop,
watermark, geotag, frame, the picked sim) was gone as soon as the photo
was reopened from the library in a later session.
Keep the whole StudioState instead and restore it when a library photo is
opened; rows written by older builds — a flat recipe — are still readable,
so photos edited before this change open with their look intact.
SAVE PHOTO is untouched: that remains the step that publishes a photo to
the landing film strip.
The library is the accounts' shelf, but the tab kept two copies of that fact: the
screen read `/me` once as it mounted and then stopped listening, so a visitor who
signed in at the studio came back to the panel asking for the login they had just
given. One record, read by the studio, the landing page and the shelf alike, is
now the only copy — a sign-in anywhere is a sign-in everywhere.
- auth.ts (new): the tab's one session record. `useAuth()` reads it through
`useSyncExternalStore`, a `/me` already in flight is joined rather than
repeated, and a call that fails leaves the record *unknown* rather than signed
out, so a cold API never reads as a guest.
- TopBar: LIBRARY is a link for a member and a dead button for everyone else. An
anchor wearing `aria-disabled` still navigates on a click, and the screen
behind it would only send the guest home again — so a guest gets the shape of
the button and nothing to press.
- Library: the gate is that shared record, not a copy taken at mount. A guest who
opens `/library` straight is turned home with `replace`, so a Back press does
not walk them into the same wall. The screen is mounted the whole time the tab
is open, so the turn is for the address the visitor actually opened: a guest on
the studio stays on the studio.
- engine/library.ts: the thumbs hand the thread back. Two lanes instead of four,
a frame's worth of idle between them, and one job per frame — a second caller
joins the decode already running instead of starting another.
Verified in Chrome (stubbed API, harness run against both the dev server and the
built bundle): a guest gets a dead LIBRARY button and stays on /app; signing in at
the studio turns it into the link and opens the shelf, with no second login and no
"log in to browse" note; the same after a sign-in on the landing page; /library
opened cold as a guest lands on / with Back going to /app; opened cold signed in,
the shelf is up. On a folder of 22 frames the open runs 2 decodes at a time (was
5) and repeats no frame (44 decodes, was 56 — 12 frames were read twice); the
tiles still come out 22 on the open, 24 by hand, 22 again after a reload.
Four asks, one screen: a folder can be given the tiles it is short of, by hand
or on the way in; the rescan row says RESCAN...; and the wall of thumbnails
scores a frame without the trip to the stage.
- Library.tsx + i18n: "RESCAN FROM THE TOP" is "RESCAN..." in both languages.
The reading is unchanged — a row's roll is still read from the top, its
subfolders included.
- engine/library.ts + Library.tsx: the tile of one frame is one function now
(`makeThumb`: the store, the backup behind it, then the file's own preview
for a RAW or a HEIC and a decode for anything else). The wall's lazy path
calls it instead of keeping its own copy of the same branches.
- engine/library.ts: `missingThumbs` asks which of a folder's rows no tile was
ever drawn for, in one transaction, and `makeThumbs` makes those — a few
frames at a time, and giving up when the caller has moved on.
- Library.tsx: the folder menu carries MAKE THUMBS, which reads the row's
folder and what lies under it; and opening a folder asks for its own frames'
tiles by itself, silently, in the background — the branch too when the
screen is drawing the branch. A frame that lands after the ask is asked for
again, which is why the frame count is a dependency of the effect.
- Library.tsx: a wall card carries the same five stars the stage does, under
the picture, and rates the frame on the click. The click stops at the star,
so scoring a frame is not picking it.
Verified in Chrome at 1440x900 against OPFS standing in for the disk, three
frames with one of them in a subfolder: opening the folder leaves two tiles
(the node's own frames) and MAKE THUMBS takes the roll to three, the frame in
the subfolder included; clearing the store and reloading brings the two back
on the open; the menu reads RESCAN... and MAKE THUMBS; and the wall's fourth
star lights four, writes star 4 to the catalogue row, and takes it back on the
second click. The same checks pass on the built bundle at :8090.
Two halves of one report: the R/G/B channel picks belong on the graph, and
the chips down the sidebar were reading as a second copy of the sliders.
- ToneCurvePanel.tsx + app.css: the channel row (RGB/R/G/B and RESET) and
the .curve-tabs rules come back, so the card picks a channel again and
bends that one. Undoes the row's removal; the graph itself is unchanged.
- app.css: the strip a LIGHT panel opens is hidden on a desktop, with the
row of panel chips it is opened from. Both name the seven rows the panel
already stands in, so a desktop was drawing every knob twice — the strip
beside the sliders, and the sliders. The phone keeps it: there the panels
are the strip, not the column.
Verified in Chrome at 1440x900 and 820x700 with a photo loaded: on the
desktop the strip is gone and the card carries RGB/R/G/B/RESET, the R tab
bends the red curve while the composite stays drawn beneath it; on the
phone the strip still opens TONE -> EV..BLACK, TONE CURVE, and the card is
the same.
The floating tone-curve card opened with its own row of channel tabs
(RGB / R / G / B) and a RESET button. The panel is meant to be a graph,
so that row is gone: the card is now the head and the curve, nothing
else. The curve edits the composite rgb channel, which is what the row
selected by default anyway.
- ToneCurvePanel.tsx: drop CURVE_CHANNELS, the channel state and the
curve-tabs block; every read and write goes through 'rgb'.
- app.css: drop .curve-tabs / .curve-tab / .curve-dot / .curve-reset
and the .curve-line.ghost path that only drew the other channels.
skipped: selecting a channel other than the composite one, and RESET,
add when a channel chooser comes back on purpose.
A photo carrying EXIF GPS arrived with GPS WATERMARK already ON: adoptPhoto
set useGeotag to the presence of the position, so the file's own EXIF decided
to print a location. The stamp is the visitor's to ask for.
A new photo now opens with it OFF whatever the file carries; the position is
still read off the photo and is there the moment the chip is switched on by
hand (and the device-locate try for an EXIF-less frame is unchanged).
Verified in a real Chrome against the built bundle: a GPS photo opens OFF
with no hint, switching the chip ON reads back 'GPS read from the photo.'; a
no-GPS photo opens OFF and offers the manual entry.
Selecting thumbs and flipping SINGLE <-> ALL THUMBS crashed the view with
React #185 ("Maximum update depth exceeded") and left the app white.
useWallWindow measures after every render through a layout effect with no
dependency array, and it ended by setting state with a value it had just
found. A set made from a layout effect renders again whether or not the value
moved, so an unchanged measurement re-rendered, which remeasured, which set
again: the loop. It is now guarded on the last window actually written (a
ref), and nothing is set that the wall already stands at.
Reproduced with the throwaway storm probe against a 3000-file roll (the tree
vanished at round 2, ~50 identical renders). After the fix: 12 rounds of hard
SINGLE/ALL THUMBS toggling on the production bundle, no error, no white
screen.
Three things, all from one look at a folder of TIFF scans.
A `.tif` is no longer a RAW. Nothing here develops one, and `tif`/`tiff` sat in
`RAW_EXT` for no decoder's sake: opening a TIFF asked for PRO and its tile wore
a RAW badge, for a file the engine has nothing to hand back. Both extensions
are dropped, and a TIFF keeps its own route instead — the tile reads the file's
own pixels (`useThumbUrls`, via `tiffDevelop`) and so does the studio — so a
`.tif` still opens and still draws, it just is not a RAW any more.
The wall's render loop. `painted` was a fresh `.slice()` on every render, so
`useThumbUrls` saw a new list each time round and its effect ran again, and
again: about twenty thousand renders a second while the page sat idle, and the
file reads frozen at the first screenful, so a tile scrolled to never came up
(7 of 24 cards drawn). `painted` is memoised on `listed, wall.from, wall.to`
now — no date formats in eight idle seconds, 28 of 28 cards after a scroll.
Scrolling between the two modes. SINGLE → ALL THUMBS lands the wall on the
frame the strip was showing, centred in the window; ALL THUMBS → SINGLE swipes
the strip to the frame nearest the wall's middle, centred in the row. Each way
the frame the other mode was standing on is the one you come back to.
Two things kept a scanned `.tif` off the wall, and both had to be fixed for
its tile to come out as a picture.
CanvasKit was never up on the catalogue's route: the studio boots it when the
workspace mounts, but a visitor who only ever opens the library never does, so
the JPEG inside the file had no decoder and the tile was drawn as nothing. The
`.tif` branch now brings the engine up itself.
And the pixels were being read out of that JPEG through an image `readPixels`
handed a buffer of ours, which CanvasKit answers by throwing rather than
filling — the frame came back black to a check on the return value. It now
takes the buffer CanvasKit hands back, the form the canvas calls in this repo
have always used. Measured in the browser on a 5472x3648 JPEG-compressed scan:
the tile went from 2378 bytes of solid black to 68670 bytes at mean 189.2 sd
74.6, against the 189.3/74.6 the same picture's uncompressed copy yields.
`scripts/tiff-decode-check.mjs` gains the fixture that was broken — a
JPEG-compressed strip — judged by how far a channel strays from the libvips
reference rather than by equality, since that strip is lossy. Its bundle now
re-exports the shim alongside the reader so the two are one module instance and
the fixture's JPEG has a decoder behind it.
A `.tif` in an album drew nothing: the tile took the file's embedded JPEG —
which a TIFF has not got, so the search found the frame's own pixel data and
kept three hundred kilobytes of it as the frame's tile — and nothing else in
the app draws a TIFF either, `createImageBitmap` answering InvalidStateError
and CanvasKit's `MakeImageFromEncoded` answering null to one.
`src/engine/tiffDecode.ts` reads the file itself, strips or tiles, and hands
back a shrunk frame, which is what the tile is made of now. The tiles that
were kept are dropped once (v4) so a frame already looked at is drawn right.
exifr keeps a page-long cache of the options object it is handed, keyed by
that object itself, so a fresh literal per frame pinned a frame's worth of
tag sets (about thirty Sets) for as long as the tab lived: 3601 frames left
~16MB of heap behind, 9601 left ~50MB, and a roll of a hundred thousand
frames is what a tab cannot hold.
One options object per call site now, which is what that cache is for.
Measured on the deployed bundle: 3601 frames rest at 8MB, not 23MB.
scripts/ram-check.mjs reads a roll of many folders, queues folders behind
the reading in front of them and reports the heap left after a forced
collection, which is how those numbers were taken.
A roll read at 150ms a frame finishes before the flush clock can be told apart from a batch-only flush. At 900ms the step that watches the frames land has 14 counts to show for the reading instead of 3, and a build that only hands the rows over when a batch is full fails it.
- scan: rows go down on a clock as well as on a full batch. The reader's folder
of 26 RAWs is under one batch of 50, so nothing of it reached the screen until
the reading was over — a wall that stood empty for the whole scan and then
filled in one go. Frames now reach the screen every 400ms while the roll is
still being read, so the count climbs and the first tiles are drawn as the
frames land.
- tiles: a HEIC or a RAW has its tile written the first time it is drawn, so
every later visit reads the tile back instead of the file.
- resume: a reading a reload cut off is offered by the next visit with a chip
instead of being run behind the reader's back.
- offline listing: the desk's listing is kept whole in IndexedDB under
`recipescam-offline`/`reads`, past the 200 000 characters localStorage held,
so an offline visit opens on the listing it kept instead of on nothing.
- offline writes: a vote or a view cast with no server is held and goes out when
one answers again, with a bar that says how many are waiting.
- sw: the shell precaches its own bundle, stylesheet and icon, read out of the
document — a worker that precached only the document answered an offline
launch with a page whose JavaScript the machine did not have.
- checks in docker/frontend/scripts: tree-scan-check (counts while reading,
resume after a reload, tiles of a long roll), offline-read-check,
offline-queue-check.
A node drew every frame of the branch under it unless the reader shut the
subfolders out, so picking A drew A and everything below it. The pick is
now the scope — the node's own frames — and the branch is what the
SUB FOLDERS chip asks for.
The year filter was already read off the frames the open node drew, so
it follows the same pick. On a tree of 13 frames (r1 r2 | A/a1..a3 |
A/deep/d1 | C/c1..c6 | E/e1, one year per folder) the chip off offers
2024 on the root, 2023 on A, 2022 on A/deep and 2021 on C; the chip on
offers all five years on the root and 2023+2022 on A.
The remembered answer moves to a new key: the chip wrote its first answer
down on the very first visit, so the old key holds 'true' for every
reader who never touched it, and reading it would keep them on a default
they never chose.
A reload drew nothing until the account round trip landed, which on a
faraway API is the whole of the wait: 8.8s to the photo on the studio's
stage and 8.2s to the library's first row, against 0.9s and 0.3s now
(measured with every /api answer held back 8s).
The studio's restore effect returned early on `!authReady`. The gate is
only needed by the two files that ask a tier question — a RAW, which is
a PRO develop, and a catalogue frame, which walks `loadFile` — so it
keeps those and lets the session's own JPEG up on the first pass.
`restoredRef` stops the second pass, when /me lands, from decoding the
frame the first one already showed.
The library mounted nothing until /me answered. What the first paint
reads is now the answer the last visit got, the way the studio reads its
own session back: the frames are already on this disk and have no reason
to sit behind a round trip. An answer the API contradicts puts the note
back on screen the moment it arrives, and an API that never answers is
not written down as this account's standing.
Every range rule now names `input[type="range"]` itself, so the class-only WB
rules tied with the plain hairline that follows them and lost — both sliders
were drawing the same grey line as every other knob, and their node sat a pixel
off the thicker track. Measured on the panel: the gradients are back in amber
and blue, and the ring is centred on the line.
EXPORT only ever wrote a file, and posting it meant leaving the studio, finding
the file and uploading it again. The dialog now offers FACEBOOK, INSTAGRAM,
REDDIT and X beside the sizes, and the render goes to the network instead of the
download folder.
What the browser can do decides how, since a page may not touch another origin's
composer: a phone's share sheet opens the target app with the picture already
attached, a desktop gets the picture on the clipboard and the site in a new tab
for one paste, and an origin with no clipboard API downloads the file beside the
open site. The line under the row says so before the click.
The default ring was a solid disc on a coloured bar, which read as a crude
block next to the rest of the rail; every range input is now a hairline
track with an outline node in the accent colour, and the temperature and
tint strips keep their gradients on the track itself.
CROP, ROTATE and WATERMARK reshape the frame rather than grade it, so they
belong with the tools that work on the whole image.
The scan made a JPEG tile for every frame as it walked, so a wall of 12MP
files spent its whole budget in the walk; the tile now waits until the card
is actually drawn (makeTile + putPhotoThumb), and a rawish frame whose date
is unreadable retries at 4MB instead of stopping at the head.
The year menu was built from the whole catalogue, so it offered values the
open folder could not produce; it now follows the rows on screen and clears
the choice when a move leaves it stale.
The mark was pinned to the folder the reading was asked of, so a walk through
a whole roll said C2 while the frames under it were what was being read. It
now hangs on the folder the reading stands in — `progress.at` — and on every
row above it up to and including the roll's own row: reading D:/A/B1/C2 marks
C2, B1, A and D:, and as the walk moves the chain moves with it. A reading
that has not reached a frame yet has nowhere to stand, and stands on the
folder it was asked of, so the ring is on the column from the click.
The ring said which folder a reading was asked of by taking the row's own
name apart and comparing the pieces, which is the same path spelled twice and
only nearly the same. When the two spellings drifted the asked row never
matched, and the fallback that used to carry the mark on the roll's row had
gone, so a reading ran with nothing on the column at all.
The mark is now built with the key the walk gives the row — `folder/sub`,
through `normPath`, the same way a frame id is spelled — and a reading whose
own row is not on the column (a branch folded away, a folder gone from the
disk) falls back to the roll's own row, so a reading is never invisible.