Preflight checks
Problem
Splice Shell has a platform-neutral PTY session contract but no native Unix backend, so Linux sessions cannot spawn structured commands, exchange terminal I/O, or safely close and resize the root PTY process.
Proposed solution
Add the Unix portable-pty backend for structured argv, cwd and environment handling, shell startup, buffered UTF-8 output, input writes, process naming, and basic liveness. Bound root-process close escalation and retain the master PTY for resize safety.
Process-group descendant teardown and the remaining bounded-review warnings are intentionally deferred to PR4.
Affected area
Terminal and PTY
Alternatives considered
Using pipes would not provide terminal semantics. Expanding this slice to process-group descendant management would exceed the approved PR3 review boundary and couple follow-up lifecycle behavior to basic Unix spawn and I/O.
Additional context
This is PR3 of 15 in the stacked-to-main terminal-ai-platform-expansion delivery. It starts from merged PR1-2 at 23af77a and is limited to Unix PTY spawn/basic I/O plus bounded root close/resize safety. Native Windows CI remains required before merge; Wine cannot substitute for native ConPTY validation.
Preflight checks
status:approvedbefore work begins or a pull request is opened.Problem
Splice Shell has a platform-neutral PTY session contract but no native Unix backend, so Linux sessions cannot spawn structured commands, exchange terminal I/O, or safely close and resize the root PTY process.
Proposed solution
Add the Unix
portable-ptybackend for structured argv, cwd and environment handling, shell startup, buffered UTF-8 output, input writes, process naming, and basic liveness. Bound root-process close escalation and retain the master PTY for resize safety.Process-group descendant teardown and the remaining bounded-review warnings are intentionally deferred to PR4.
Affected area
Terminal and PTY
Alternatives considered
Using pipes would not provide terminal semantics. Expanding this slice to process-group descendant management would exceed the approved PR3 review boundary and couple follow-up lifecycle behavior to basic Unix spawn and I/O.
Additional context
This is PR3 of 15 in the stacked-to-main
terminal-ai-platform-expansiondelivery. It starts from merged PR1-2 at23af77aand is limited to Unix PTY spawn/basic I/O plus bounded root close/resize safety. Native Windows CI remains required before merge; Wine cannot substitute for native ConPTY validation.