just-bash-compat

name	just-bash-compat
description	Adapt Bash scripts for just-bash compatibility. Use when a script must run inside just-bash, behaves differently from native Bash, or needs a just-bash shell-semantics regression test.
disable-model-invocation	true

just-bash compatibility

Use a differential loop: native Bash is the semantic baseline, while the project's real just-bash integration is the compatibility target.

Steps

1. Make the mismatch red. Identify the installed and locked just-bash version, then run the unchanged script with the same arguments under native Bash and the project's actual just-bash integration. Capture stdout, stderr, and exit status from both. Exercise the integration's real filesystem, custom commands, environment, and Bash options; a bare new Bash() misses integration-specific behavior when those differ.

   Completion criterion: a deterministic reproducer passes under native Bash and fails under the exact just-bash path the project uses, or proves the bug is outside just-bash.

2. Minimize the boundary. Reduce the reproducer to the smallest construct that still differs. Classify it as parser/expansion behavior, set -e control flow, script argument passing, built-in command behavior, or project integration. For those classes, consult known compatibility boundaries and probe the installed version before relying on an existing workaround.

   Completion criterion: one minimal probe identifies the failing boundary and its observed behavior on the installed version.

3. Preserve semantics. Edit the canonical source script and keep native Bash behavior intact. Replace only the unsupported boundary. Preserve success output, expected no-result behavior, and genuine failure propagation. When just-bash cannot represent an interface, provide a compact supported form, document it as the preferred form, and make the unsupported form fail loudly rather than silently dropping data.

   Completion criterion: the minimized probe is green in both runtimes, with every expected failure retaining a non-zero result.

4. Verify the script as users invoke it. Re-run the complete script under native Bash and the real just-bash integration. Cover successful output, expected empty/no-server/no-match behavior, unexpected command failure, and every documented argument form affected by the change. Verify generated or deployed copies only as outputs; keep edits in the canonical source.

   Completion criterion: every affected branch has matching intended semantics in both runtimes, checks for the owning project pass, and temporary sessions, sockets, files, and probes are removed.