commands sometimes start backgrounded

[rsgalloway]

One-off commands sometimes start backgrounded and require fg to complete.

When running one-off commands via:

envstack [stack] -- <cmd>

some commands appear to start in a backgrounded or stopped state and require the user to manually run fg to resume execution. This is unexpected and breaks both interactive usage and scripting.

Commands launched via envstack -- should:

• Run in the foreground
• Be attached to the controlling TTY
• Never require job control interaction (fg, bg)
• Exit cleanly when the command completes

Behavior should match running the same command directly in the shell with the environment applied.

[rsgalloway]

This appears related to job control / PTY handling when spawning subprocesses (e.g. shell invocation mode, TTY attachment, process groups). Commands that expect an interactive or foreground context may be receiving SIGSTOP/SIGTTIN/SIGTTOU or losing their controlling terminal.

[rsgalloway]

running two envstack commands in series inside a Makefile produces the issue:

test:
    envstack -- ls -al
    envstack -- which python

[rsgalloway]

removing the interactive -i flag from bash commands seems to address the issue