fix(cli): recover terminal state after interrupting a running turn (#33271) - #54058
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…ol sequence freeze When the agent is interrupted during processing, prompt_toolkit's renderer and VT100 input parser can be left in an inconsistent state. CSI 6n cursor position report responses leak as literal text (^[[19;1R) and the terminal stops accepting keyboard input. Fix: in process_loop's finally block, after an interrupted turn: - flush_stdin() to drain stray escape bytes from the OS input buffer - _force_full_redraw() to reset prompt_toolkit's renderer cache Closes #33271
Pull the #33271 post-interrupt recovery (flush_stdin + _force_full_redraw) out of process_loop's finally block into _recover_terminal_after_interrupt(), and replace the inline-logic-copy tests with ones that exercise the real helper plus a source guard that process_loop still invokes it behind the _last_turn_interrupted gate.
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tonydwb
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Jun 28, 2026
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Code Review Summary
Verdict: Approved
Adds terminal recovery after user-interrupted agent turns. When the user types during a running turn, prompt_toolkit's in-flight CSI 6n cursor query can leak as literal text and stall the VT100 parser. The recovery path drains stray escape bytes (flush_stdin) and forces a clean redraw (_force_full_redraw). Both steps are independently safe. Tests cover the helper, ordering, TTY gating, and process_loop wiring behind the _last_turn_interrupted guard.
Reviewed by Hermes Agent
This was referenced Jun 28, 2026
Closed
This was referenced Jul 29, 2026
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Summary
Interrupting a running CLI turn by typing a new message no longer freezes the terminal. After an interrupt, the CLI now drains stray escape bytes from stdin and forces a clean prompt_toolkit repaint, so a leaked
CSI 6ncursor-position reply can't stall the input parser.Closes #33271. Salvaged from #34064 (@zccyman).
Root cause
process_loop'sfinallyblock only calledapp.invalidate(). On an interrupt, prompt_toolkit could have an in-flightCSI 6nquery whose reply (ESC[<row>;<col>R) arrived on stdin after the parser tore down — leaking as literal^[[19;1Rand stalling the VT100 parser, accepting no further keystrokes. The existing CPR-suppression machinery (#13870/#48309) only engages on SSH/tunnel terminals, leaving local terminals (where the bug also reproduces) unprotected on the interrupt path.Changes
cli.py: after an interrupted turn (_last_turn_interrupted), callflush_stdin()(termios.tcflush(TCIFLUSH), no-op on non-TTY) then_force_full_redraw(). Extracted into a testable_recover_terminal_after_interrupt()helper.tests/cli/test_terminal_interrupt_recovery.py: tests exercise the real helper (drain-then-redraw order, redraw survives a flush failure, TTY-gating) plus a source guard thatprocess_loopactually invokes it behind the_last_turn_interruptedgate.Validation
app.invalidate())flush_stdin+_force_full_redrawtests/cli/test_terminal_interrupt_recovery.pytests/cli/test_cli_force_redraw.pyInfographic