debug-tui

Debugging the keifu TUI headlessly

keifu has a built-in remote-control server. You can run the real app without a human at the terminal: send key/mouse input through the same code paths as real input, dump the rendered screen as plain text, and read the app state as JSON. The reliable workflow is always: drive → dump → assert, both to reproduce a bug and to prove the fix.

Launch

cargo build
PORT=7167   # pick a fresh port per run to avoid stale instances
timeout 120 script -qec "./target/debug/keifu --debug-listen 127.0.0.1:$PORT --log-file /tmp/keifu.log" /dev/null >/dev/null 2>&1 &
sleep 2

• script allocates a PTY; keifu cannot enable raw mode without one. The timeout wrapper guarantees stray instances die even if you forget to quit.
• The script PTY reports size 0x0, so the main loop skips real rendering. Consequence: pane layout for mouse hit-testing is only recorded when a render happens — always send a dump with explicit width/height before any mouse command, and give mouse coordinates in that dump's space.
• keifu operates on the repository of its working directory. To exercise staging/commit/push, launch it inside a throwaway repo (mktemp -d + git init), never the real working repo.

Protocol

Newline-delimited JSON over TCP; each request line gets one JSON response line.

printf '%s\n' '{"cmd":"state"}' | nc -q1 127.0.0.1 $PORT

For "feels slow" reports, use the log: ops over 10ms are written live as slow operation, and quitting writes a per-op perf summary (count/avg/max). Reproduce → quit → grep the log file.

Every response is one JSON line. dump returns the screen as an escaped string in the screen field — pipe through jq -r .screen to read it. For single requests prefer nc -q1 (closes after the response); only multi-line batches need plain nc under timeout.

Key token syntax: whitespace-separated; single chars as-is (uppercase implies Shift); special keys <enter> <esc> <tab> <backtab> <space> <up> <down> <left> <right> <home> <end> <pgup> <pgdn> <backspace> <c-x> (Ctrl+x). To type a word in an input dialog, space-separate the letters: c f i x <space> b u g <enter>.

Full protocol details: docs/debugging.md. Implementation: src/debug_server.rs.

Gotchas that will waste your time

• Double-click = two clicks on the same cell within 400 ms. Separate nc invocations are too slow — send both clicks (plus the leading dump that records the layout) in ONE connection:

  printf '%s\n%s\n%s\n%s\n' \
    '{"cmd":"dump","width":110,"height":30}' \
    '{"cmd":"mouse","kind":"click","x":60,"y":24}' \
    '{"cmd":"mouse","kind":"click","x":60,"y":24}' \
    '{"cmd":"state"}' | timeout 4 nc 127.0.0.1 $PORT
  

• Commands are processed after the event-poll tick, so responses can lag up to ~200 ms; wrap nc in timeout and don't interpret slowness as a hang.

• A held-open nc may exit non-zero via timeout even after delivering the response — check the output, not the exit code.

• Injected input bypasses the terminal's input layer. keys/mouse commands go straight into the app, so they cannot verify anything that depends on terminal modes — e.g. mouse tracking escape sequences (?1000/?1002/?1003) set in src/tui.rs. Changes there need a human in a real terminal.

• q only quits from the graph pane. If another pane is focused or a popup is open (e.g. after a mouse click), q/<esc> first returns focus/closes the popup and the app keeps running. Send {"cmd":"keys","keys":"q q"} and confirm exit: a follow-up nc connection must be refused. (pgrep -af keifu matches your own shell's command line — don't trust it.)

Verification loop

1. dump and confirm the precondition is on screen (e.g. the row you'll click).
2. keys / mouse to act.
3. state + dump, then assert: grep the dump for expected text, compare selected_index / mode / focused_pane in the state JSON.
4. Quit, and read /tmp/keifu.log for the tracing trail (KEIFU_LOG=trace for more detail; useful for async diff-load issues).

A fix is not verified until step 3 shows the corrected behavior on a dump that previously showed the bug.