Not only is this nicer code (and more idiomatic at least in this code
base), but it also avoids linter warnings about missing preallocations
(lo.Map does preallocate the result array).
A cmd/pty re-render used to overwrite the displayed buffer from the top
down as lines arrived, relying on keeping the previous render's view-line
tail to avoid a blank frame. That left the view showing a mixture of old
and new content while loading, and any reader (draw, clicks, the
view-line mapping) could observe a half-written buffer at the wrong
scroll.
Instead, build the new content in a second, off-screen viewBuffer: until
the task has read enough to paint, writes go there and the displayed
buffer — and so everything every reader sees — is left untouched. Once the
task reaches its first-paint point (InitialRefreshAfter, or EOF for short
content) it swaps the off-screen buffer in atomically, so the view jumps
straight from the previous render to the new one with no intermediate
frame. Subsequent lines append to the now-displayed buffer.
Swapping at the first-paint point means the displayed buffer is only a
viewport tall when it appears and then grows as the rest streams in toward
the count needed for an accurate scrollbar. The scrollbar is sized from the
displayed buffer's height, so left to itself the thumb would shrink and
snap back during that growth (most visibly: the files panel's periodic
refresh making the thumb jump while scrolled down). The total height the
scrollbar needs is a strictly later quantity than the viewport-fill paint,
so no single early swap can have both right. FreezeScrollbarHeight therefore
records the view's height when a load begins and the scrollbar is held there
— growing only if the new content turns out taller — until the load ends; a
synchronous render superseding the load releases it. This mirrors the layout
clamp, which already ignores the partial content height while a view loads.
With the swap doing a wholesale replace, refreshViewLinesIfNeeded can
truncate the view lines to the current buffer: there is no longer a
half-loaded shorter buffer whose tail we must keep showing, so a stale
tail never forms. clear()/Reset() abandon any in-progress off-screen
render so a synchronous SetContent after a stopped task writes to the
display.
The swap holds writeMutex for now; it could later move to the main thread.
Flicker behaviour still needs interactive verification (LAZYGIT_SLOW_RENDER
+ a real diff renderer).
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The fields that make up a view's content and the act of writing to it —
the cell buffer (lines), the write cursor (wx/wy), the escape-sequence
decoder (ei) and the held-newline flag (pendingNewline) — were loose
fields on View. Bundle them into a viewBuffer struct that View holds by
pointer. This is a behaviour-preserving prep refactor: every access just
goes through v.buf now. It sets up rendering into a second, off-screen
viewBuffer that can be swapped in atomically, so an async re-render never
exposes a half-written buffer to readers.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
When using lazygit in a multi-tab terminal it is useful to see if the
lazygit tab is currently active; ghostty does a very good job at dimming
down the inactive tabs, but VS Code's builtin terminal does not, so
indicate this on our side by removing the green highlight from panel
frames and tab titles, and showing the selection as inactive like we do
for a side panel when the main view is focused.
ConPTY compresses runs of default-colored spaces into ECH + CUF
(\x1b[NX\x1b[NC) instead of emitting them literally. ECH is still a
no-op for us — our buffer is built sequentially and has nothing to
erase — but CUF has to materialize as N visible space cells so the
gap actually appears, otherwise content the child wrote with leading
indentation slides left against the preceding cell.
The view's cursorForward branch reuses the same machinery as tab
expansion: substitute the trigger byte for a space and let the
repeatCount path emit the cells under the parser-tracked SGR. The
existing notifyCellsWritten plumbing then advances screenCol over
the gap, keeping subsequent CUP targets aligned.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
ConPTY compresses runs of default-colored spaces into ECH + CUF
(\x1b[NX\x1b[NC) rather than emitting them literally. Both currently
fall through the parser's swallow path, so the gap they describe
collapses entirely and content that the child wrote with leading
indentation ends up slid left against the previous cell.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
ConPTY presents its child's output as a screen buffer and uses CUP /
CUD / CNL / VPA to skip over blank rows rather than emitting LFs. The
previous behaviour swallowed all of those and the visible content
collapsed together. Now the escape parser tracks the screen-relative
cursor row, and any CSI that moves the cursor past the current row
emits a cursorDown instruction that the view turns into the matching
number of empty lines.
Column tracking is deliberately omitted: doing it correctly would mean
duplicating the view's grapheme-cluster width math in the parser, and
ConPTY in practice positions to column 1 after a CR-equivalent, which
the existing wx-reset path already handles. ConPTY-internal scrolling
needs no special handling either: it only emits cursor-positioning
escapes within the first, un-scrolled screenful — once its screen
scrolls it switches to plain linefeeds, which the view advances on
directly regardless of the tracked cursor.
Backward cursor moves are silently dropped — the view's buffer is
append-style and can't undo earlier writes. The exception is cursor-home
(CUP to row 1): ConPTY emits it at the start of every screen, so rather
than drop it we re-anchor the row tracking to the current write position.
Without that, a view not rewound in lockstep with ConPTY's screen (the
command log, which streams pty output without a rewind) accumulates
drift, and every later absolute CUP becomes a dropped backward move that
collapses the rows ConPTY positioned with.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
ConPTY presents its child's stdout as a screen buffer and uses CUP
(`\x1b[<row>;<col>H`) to skip over blank rows rather than emitting LFs
for them. Our escape interpreter swallows CUP via the catch-all
"valid CSI final byte we don't implement" branch, so the blank rows
the child put between non-blank ones disappear and the surrounding
lines collapse together — which is what makes the delta-rendered diff
in the screenshot look like its blank lines and section breaks were
removed.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Tools like delta paint each diff line's background with '\x1b[K' so
the color reaches the right edge. Up to now the '\x1b[K' handler
appended (InnerWidth - cx) explicit padding cells with the fill bg
so rendering picked up the color. That worked for short lines but
silently degraded once content exceeded InnerWidth: the repeat
count went non-positive, no cells were added, and after wrapping
the partial tail segment was left without any cells carrying the
fill color, so draw() fell back to the view's default bg.
Record the fill colors on the source line as optional
trailingFillAttributes. In the '\x1b[K' handler set them (and drop
the padding-cell loop — the metadata covers both the wrap and the
non-wrap cases). In draw(), once per source line, pick the trailing
cell's fg/bg from the metadata if present and otherwise from the
view defaults; then the inner-loop fills past-content cells with
that.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The sentinel was appended to every \n-terminated line solely so that
draw()'s prevFgColor tracking would reset to default for the trailing
area; without it, an AttrReverse-styled last cell would carry its
rendered bg past the end of the line.
The same prevFgColor mechanism propagated AttrReverse past content on
*unterminated* lines too — which doesn't match real terminal behavior
(try `print '\x1b[7m\x1b[31mfoo'` in a shell: the reverse stops at
the last character) and isn't relied on by anything in lazygit, since
all our writers terminate lines with \n.
Drop the sentinel cell, drop prevFgColor, and just have draw() paint
trailing cells with the view's default fg/bg. The
TestUnterminatedReverseLineExtendsToEdge regression test inverts to
document the new (terminal-matching) behavior, renamed accordingly.
TestWriteString expectations also drop the trailing "" that came
from the sentinel.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The cells of a source line will soon need to carry metadata about how
the line was terminated (newline vs filled to edge via \x1b[K). Move
to a struct so there's somewhere to put it; this commit only renames
[][]cell to []line{cells: ...} with no behavior change.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Tools like delta emit each diff line with the bg color set, then
\x1b[K to fill the rest of the row with that bg color. When the
content fits within the view's inner width, gocui's \x1b[K handling
appends explicit padding cells and rendering works. When the content
exceeds the inner width, \x1b[K adds no cells (negative repeat
count), the line is wrapped into multiple segments, and the partial
tail segment's trailing cells fall back to the view default bg
instead of continuing the fill color.
Add a test that drives draw() against a tcell mock terminal and
asserts the current (buggy) trailing background.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The next few commits restructure how the view's draw() decides the
fg/bg of cells past the end of a line's content. Pin down three
existing behaviors first so the restructuring stays a refactor:
- '\n' should reset attributes for the trailing area so a reversed
final cell doesn't bleed into empty space.
- An unterminated line with AttrReverse on its last cell should
propagate that to the right edge (otherwise the rendered bg
abruptly stops at the last character).
- '\x1b[K' on a line that fits within InnerWidth should fill the
remaining cells with the current bg color.
Introduce a small WithSimulationScreen helper that swaps in a tcell
mock terminal so tests can call view.draw() and inspect rendered
cells via Screen.Get().
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
I copied all files except dot files (.github and .gitignore), the _examples
folder, and go.mod/go.sum.
At some point we may want to copy the files back to the gocui repo when other
clients (e.g. lazydocker) want to use the newer versions of them.
Stefan Haller
