Stefan Haller b4fb49acce Render async content into an off-screen buffer and swap it in ... 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, the diff-line mapping, clicks) could observe a half-written buffer at the wrong scroll — the §11 Race A flicker and the §8 stale-tail mapping both came from this. 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 and applies the saved scroll in the same step, 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 the stale tail (§8) never forms. clear()/Reset() abandon any in-progress off-screen render so a synchronous SetContent after a stopped task writes to the display. This replaces the holdViewLines and freshViewLineCount patches reverted in the previous two commits with one mechanism. 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 pager). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>		2026-08-08 12:58:59 +02:00
..
async_handler.go	Copy gocui files into lazygit repo under pkg/gocui	2026-04-30 14:29:08 +02:00
async_handler_test.go	Copy gocui files into lazygit repo under pkg/gocui	2026-04-30 14:29:08 +02:00
tasks.go	Render async content into an off-screen buffer and swap it in	2026-08-08 12:58:59 +02:00
tasks_test.go	Render async content into an off-screen buffer and swap it in	2026-08-08 12:58:59 +02:00