fix(tui): reassemble fragmented escape sequences before Bubble Tea parses them (#107)

* fix(tui): reassemble fragmented escape sequences before Bubble Tea parses them

A terminal read can end in the middle of an escape sequence — most visibly
an SGR mouse report. Bubble Tea v1 parses each read independently, so the
pending ESC[ becomes an Alt+[ keypress and the printable tail is delivered
as ordinary text, typing garbage like 65;75;25M into the composer. #106
only stripped tails of reports split after a lone ESC; measured, 19 of 21
two-way split points still leaked.

AssembleInput (internal/tui) wraps the terminal input stream and holds an
undecidable head until the bytes that complete it arrive, so Bubble Tea
sees whole sequences: SGR and X10 mouse reports, SS3 keys, CSI, and OSC/
DCS-style string sequences. A mouse-shaped head whose tail never arrives
is dropped instead of echoed (keeping any bytes typed after it), a lone
ESC is released after 10ms so esc still closes popups, bracket-paste
bodies are never altered, and releases never cut a paste marker. The
wrapper presents itself as a term.File with the real descriptor — Bubble
Tea only puts a recognised file into raw mode, and cancelreader probes the
same shape — while Close stops the pump without closing stdin, which the
program does not own. Only a terminal file is wrapped; pipes and redirects
keep Bubble Tea's own handling.

Wired in buildProgramOptions, non-Windows. FilterShiftEnter's regex strip
stays as a backstop. Tests cover every two- and three-way split of every
report shape, bursts, typing around split reports, pastes (incl. 240KB),
stalled and slow reports, EOF, SS3/OSC joins, and end-to-end parsing
through a real tea.Program.

* fix(tui): consume input synchronously so kqueue never strands keystrokes

The reassembler's pump goroutine drained the terminal eagerly into a
channel. Bubble Tea's kqueue/epoll cancelreader waits on the file
descriptor, so bytes already drained were invisible to it: input that
arrived while the program was between reads (delivering the previous
message) was stranded until an unrelated later keystroke woke the
loop. Reads now consume the source synchronously one read at a time,
waiting via poll(2) for the settle/abandon windows, so bytes stay in
the kernel buffer until they are read and every wakeup stays coherent.

The test harness drives real tea.Program runs over an os.Pipe, which
Linux's epoll cancelreader requires; each script chunk is written as
its own read to keep split points real.

Author: jkyberneees

AGENTS.md

@@ -148,7 +148,8 @@ feat(tui): compact tool steps with Ctrl+E details toggle
   wall latency.
 - `internal/tui` is split by responsibility: `model.go` holds the core
   model, `inspect.go` owns transcript item focus and bounded tool paging, `events.go` event handling, `input.go` key/text input,
-  `approval.go` the approval flow, `chrome.go` drawer-sheet / shelf /
+  `input_reassembler.go` the raw terminal input stream, `approval.go`
+  the approval flow, `chrome.go` drawer-sheet / shelf /
   header-instrument / session-home layout, `reconnect.go` socket recovery.
   Put new code in the matching file instead of growing `model.go`.
 - First-run home (`welcome` in `banner.go`) is the working directory plus
@@ -162,7 +163,22 @@ feat(tui): compact tool steps with Ctrl+E details toggle
   keys". `FilterShiftEnter` rewrites those CSI sequences (and the
   remapped `^C` / `^K` / esc) back into KeyMsgs — Codium/Cursor encode
   Ctrl+C as CSI once those modes are on. `RestoreEnhancedKeys` clears
-  leftovers on startup and shutdown. Alt-screen always enables mouse
+  leftovers on startup and shutdown. A terminal read can end mid-sequence:
+  `AssembleInput` (wired in `buildProgramOptions`, non-Windows) reassembles
+  it before Bubble Tea parses each read. Partial `ESC [ < …` heads wait for
+  their tail; a mouse-shaped head whose tail never arrives is dropped — never
+  echoed into the composer. Only the SGR form is disposable: the legacy X10
+  form is joined but never dropped, because its coordinate bytes are
+  indistinguishable from typed text. Bracket-paste bodies are user data and
+  are never dropped, whatever they contain. A mouse head a fresh read cannot
+  continue is a truncated report and is discarded so the read is not eaten.
+  The wrapper only wraps a terminal file; a pipe or redirected stdin keeps
+  Bubble Tea's own handling. It also presents itself as a `term.File` with the
+  real descriptor, because Bubble Tea enables and restores raw mode only for
+  input it recognises as a file (`tty_unix.go` `initInput`) — a plain wrapper
+  would leave the program in cooked mode. One pump goroutine per program
+  instance; `Close` stops it without closing stdin, which the program does not
+  own. Alt-screen always enables mouse
   cell-motion so the wheel scrolls (and clicks hit turn heads / answer
   cards / steps / the queue). A left-click on an answer card (or a
   collapsed summary) copies that turn's `msg.content` — final or the

README.md

@@ -656,6 +656,11 @@ never become the weakest link:
 - **Mouse wheel blocks native text selection** — the alt-screen always
   reports the mouse so the wheel can scroll. Click a reply card to copy
   it, or use `^Y` / `alt+y`. `--plain` keeps the terminal's own scrollback.
+- **Garbage like `65;75;25M[<65;75;25M` appears in the composer while
+  scrolling** — the terminal split a mouse report across reads. bodek
+  reassembles the input stream before Bubble Tea parses it, so every split
+  point is covered: press `^U` to clear any text from an older build, and
+  `bodek upgrade` if you are not on the latest release.
 - **Colors look wrong** — try `/theme classic`, check `TERM`; `NO_COLOR=1`
   forces a colorless render everywhere.
 - **Connection dropped mid-turn** — bodek retries with backoff (5 attempts)

cmd/bodek/main.go

@@ -9,6 +9,7 @@ import (
 	"io"
 	"os"
 	"os/signal"
+	"runtime"
 	"strings"
 	"syscall"
 
@@ -114,6 +115,14 @@ func buildProgramOptions(plain bool) []tea.ProgramOption {
 	// Filter first so Shift+Enter CSI sequences become a KeyMsg before
 	// any other option's machinery sees them.
 	opts := []tea.ProgramOption{tea.WithFilter(tui.FilterShiftEnter)}
+	// A terminal read can end in the middle of an escape sequence — most
+	// visibly a mouse report. Bubble Tea parses each read independently, so
+	// a split report would land in the composer as text: reassemble the
+	// stream before it gets there. Windows keeps the console input reader
+	// Bubble Tea owns (coninput), which this wrapper would bypass.
+	if runtime.GOOS != "windows" {
+		opts = append(opts, tea.WithInput(tui.AssembleInput(os.Stdin)))
+	}
 	if !plain {
 		// The alt-screen transcript is the default surface. Linear mode
 		// (--plain) stays on the main buffer so printed lines persist in

cmd/bodek/main_test.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"testing"
 
@@ -101,8 +102,14 @@ func TestParseConfigHelp(t *testing.T) {
 
 func TestBuildProgramOptionsDefault(t *testing.T) {
 	opts := buildProgramOptions(false)
-	if len(opts) != 3 {
-		t.Fatalf("expected 3 default program options (filter, alt-screen, mouse), got %d", len(opts))
+	// filter + input assembler + alt-screen + mouse (the assembler is
+	// skipped on Windows, where Bubble Tea owns the console reader).
+	want := 4
+	if runtime.GOOS == "windows" {
+		want = 3
+	}
+	if len(opts) != want {
+		t.Fatalf("expected %d default program options (filter, assembler, alt-screen, mouse), got %d", want, len(opts))
 	}
 	// Sanity check: the option is callable like a real tea.ProgramOption.
 	var p tea.Program
@@ -111,8 +118,14 @@ func TestBuildProgramOptionsDefault(t *testing.T) {
 }
 
 func TestBuildProgramOptionsPlain(t *testing.T) {
-	if opts := buildProgramOptions(true); len(opts) != 1 {
-		t.Fatalf("plain mode must skip alt-screen and mouse (filter only), got %d options", len(opts))
+	// Plain mode keeps the filter and the input assembler, and skips
+	// alt-screen and mouse.
+	want := 2
+	if runtime.GOOS == "windows" {
+		want = 1
+	}
+	if opts := buildProgramOptions(true); len(opts) != want {
+		t.Fatalf("plain mode must skip alt-screen and mouse (filter + assembler only), got %d options", len(opts))
 	}
 }
 

go.mod

@@ -8,8 +8,11 @@ require (
 	github.com/charmbracelet/glamour v1.0.0
 	github.com/charmbracelet/lipgloss v1.1.1-0.20250404203927-76690c660834
 	github.com/charmbracelet/x/ansi v0.11.8
+	github.com/charmbracelet/x/term v0.2.2
+	github.com/muesli/cancelreader v0.2.2
 	github.com/muesli/termenv v0.16.0
 	golang.org/x/net v0.58.0
+	golang.org/x/sys v0.47.0
 )
 
 require (
@@ -20,7 +23,6 @@ require (
 	github.com/charmbracelet/colorprofile v0.4.3 // indirect
 	github.com/charmbracelet/x/cellbuf v0.0.15 // indirect
 	github.com/charmbracelet/x/exp/slice v0.0.0-20260816001655-68d539dca504 // indirect
-	github.com/charmbracelet/x/term v0.2.2 // indirect
 	github.com/clipperhouse/displaywidth v0.11.0 // indirect
 	github.com/clipperhouse/uax29/v2 v2.7.0 // indirect
 	github.com/dlclark/regexp2/v2 v2.7.1 // indirect
@@ -32,13 +34,11 @@ require (
 	github.com/mattn/go-runewidth v0.0.28 // indirect
 	github.com/microcosm-cc/bluemonday v1.0.27 // indirect
 	github.com/muesli/ansi v0.0.0-20230316100256-276c6243b2f6 // indirect
-	github.com/muesli/cancelreader v0.2.2 // indirect
 	github.com/muesli/reflow v0.3.0 // indirect
 	github.com/rivo/uniseg v0.4.7 // indirect
 	github.com/xo/terminfo v1.0.0 // indirect
 	github.com/yuin/goldmark v1.8.5 // indirect
 	github.com/yuin/goldmark-emoji v1.0.6 // indirect
-	golang.org/x/sys v0.47.0 // indirect
 	golang.org/x/term v0.45.0 // indirect
 	golang.org/x/text v0.41.0 // indirect
 )