Tcl 8.6 windows console channels expose no -inputmode configure key, so
punk::console guards testing -inputmode/-mode classified a real 8.6 console
as a pipe. A twapi console handle for stdin is now treated as definitive
console detection at all three affected sites (stdin only - pipe probes
still never touch the process console; mintty-as-pipes has no console
handle and falls through to the env heuristics as before):
1. get_ansi_response_payload's raw-cycling gate (introduced 0.1.5) skipped
the raw cycle for 8.6 line-mode queries.
2. is_input_console_or_tty returned a false negative, making
settle_can_respond's layer-2 heuristic settle a real 8.6 console as
unable to respond.
3. input_at_eof (introduced 0.1.2) took the pipe branch and performed its
probe read on the drained console channel. This was the line-mode query
killer: verified empirically against clean tclkits 8.6.13 and 8.6.17,
a read on a drained 8.6 console channel makes the channel driver park a
blocking cooked-mode ReadConsole; driver reads sample the console mode
when issued, not when data arrives, so the query's subsequent raw flip
cannot rescue it and the terminal response is swallowed until Enter.
Since get_ansi_response_payload calls input_at_eof immediately before
its raw cycle, every 8.6 line-mode query timed out (~500ms) with the
response later leaking to the line reader as phantom input - also the
source of increased ANSI artifacts (e.g. 'help env') once 0.7.0
brokering made code-interp queries actually reach the terminal.
Interactively verified on punksys (tcl 8.6.13, src launch): line-mode
get_cursor_pos and dec_get_mode succeed mid-command, brokered query loops
run clean, and typed-ahead lines are recovered without phantom input.
Known residue (documented in the G-007 detail notes): queries fired while
the repl reader is armed and idle at a line-mode prompt (including some
repl-init detection queries) still hit the parked-read limitation on 8.6 -
repl init ordering is a follow-up; raw mode is unaffected.
Tests: probes.test gains constraint-gated wiring tests for the twapi
console branch of is_input_console_or_tty and input_at_eof (skip in piped
runs, engage on a real console). Full suite passes at baseline (exec-14.3
only) under Tcl 9.0.3; probes suite also verified under Tcl 8.6.
Assisted-by: harness=claude; primary-model=claude-fable-5; api-location=anthropic.com
Julian Noble
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