Sharing one `ScrollState` across the viewer's rows was not enough to make
them move together. `Modifier.horizontalScroll` is a node per row, and each
one coerces the shared offset into *its own* range -- its content width
less its viewport -- so a short line's range is zero and it stayed put
while the long line beside it moved. Each row also writes `maxValue` on the
shared state as it measures, so how far the file could be dragged at all
was decided by whichever row happened to measure last, and changed as the
list scrolled.
Both go away once every row is the same width. `FileLines` now carries the
longest line in columns, and the viewer turns that into one content width
from a single character's advance -- arithmetic rather than twenty thousand
measurements, because the face is monospace -- and gives it to every row. A
tab counts as eight columns and deliberately upwards: over-estimating
leaves a little empty space past the longest line, under-estimating puts
the end of that line out of reach. The width is capped well under what
`Constraints` can carry, so a minified file is a scroll that stops early
rather than a crash.
Reported by Iris on 2026-09-04. Checked on the emulator against the
generated 1 MB file, whose lines run from one character to sixty-eight:
the file now moves as a block, the offset survives scrolling vertically and
newly composed rows arrive at it, and the far end of the longest line is
reachable. Also checked on the two cases the change had no reason to touch
-- a file narrower than the screen, which still does not scroll at all, and
an empty one, whose zero content width draws its one numbered line.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The other half of EXPLORER.md: a folder button on the session header opens
the machine's filesystem, starting where the session works.
It draws **over** the session in the same `Box`, so the session under it
stays composed -- its event stream keeps flowing, its draft and scroll
position stay where they were, and coming back from a file costs nothing.
Back steps one level inside it (editor, viewer, directory, parent) and only
closes from where it opened; the platform gesture, the button and the swipe
all go through the one function, so they cannot mean different things.
The viewer is a `LazyColumn` of lines rather than one `Text`, because text
layout is linear in the text and a twenty-thousand-line file in a single
`Text` measures all of it to draw a screenful. Lines do not wrap and share
one horizontal scroll, so a logical line is a visual line and the gutter
cannot come to number the wrong text; the gutter's width is measured from
the digit count of the line count in the style it is drawn in. The editor
is a `BasicTextField` with a `VisualTransformation` carrying the scanner's
spans, which is the one Compose API that colours a field's own text rather
than replacing the field.
`fileLanguage` reads the same table `fenceLanguage` does, so a language
added for fences is a language added for files.
A file that changed on the machine while it was open here refuses to be
overwritten and asks, with what each of the three answers costs. That is
the ordinary case, not the exotic one: an agent editing the file somebody
is reading is what this whole feature is for.
The speedometer moves off the header into the session settings dialog,
where the session's other about-the-session controls are, and the folder
takes a place between the usage chart and the cog -- widest scope to
narrowest, cog at the end, as Iris asked. Both benchmark scripts move onto
`ui-trace`'s new tap-by-label action in the same change, so the render
report is never unavailable and never pressed at a coordinate that has
stopped meaning anything; `app/bench-lib.sh` is what they share, and
`grep -n "tap [0-9]" app/*.sh` is the check.
Exercised on the emulator against the sandbox's new fixture tree, with a
screenshot or a ui-trace for each: the listing (dotfiles, directories
first, a symlink to a directory sorted with them, a name with a tab in it),
a highlighted file, binary, too big, a permission error, editing and
saving, the 409 and its Overwrite, back with unsaved edits, creating a name
that exists, creating one that does not and landing in the editor, an empty
directory, and `..` above the directory the session opened in.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
irisandClaude Opus 5