nucleic-brush/NUCLEIC_FORK.md

Nucleic fork of brush

Vendored copy of reubeno/brush, pinned at tag brush-shell-v0.4.0 (upstream commit 96a26d0), consumed by the shell/ workspace to build nash, the Nucleic agent shell (docs/NASH.md).

Every fork change is marked with a // nash: comment. Current patches:

File	Change
brush-shell/src/productinfo.rs	PRODUCT_NAME → nash; display string identifies the fork
brush-shell/src/args.rs	usage/version strings rebranded
brush-core/src/prompt.rs	\$ (PromptPiece::DollarOrPound) renders the atom sign ⚛ (U+269B) for non-root instead of $; root still shows #
brush-core/src/expansion.rs	corpus divergence D1: added ExpansionPiece::LiteralText — literal unquoted text is never field-split (bash splits only expansion results) but keeps glob characters active. Parameter-expansion substitutions (${v:-word} etc.) convert back to splittable at the expansion boundary; ExpanderOptions.field_split_literal_text lets data-string callers opt in. Upstream candidate.
brush-core/src/completion.rs	compgen -W word list opts into field_split_literal_text (the -W string is data)
brush-shell/tests/cases/compat/ifs.yaml	removed known_failure from 3 IFS tests the D1 fix repairs
brush-core/src/gate.rs (new) + lib.rs	the Gate trait (docs/NASH.md §4.2): process-global, verdict-shaped hook; allow-all default so an unconfigured shell behaves exactly like upstream
brush-core/src/commands.rs	SimpleCommand::execute split into gate wrapper + execute_inner: on_exec before dispatch (Deny short-circuits), completion correlated through all three spawn-result variants
brush-core/src/processes.rs	ChildProcess.gate_token + on_exit reporting from wait()/poll() (128+signal for signal deaths)
brush-shell/src/entry.rs	set_exit_hook seam so nash can flush its event buffer before process::exit
brush-core/src/gate.rs	M2 (docs/NASH.md §5.2–5.3): RedirectRecord/RedirectReadback + ExecStart.redirects + Gate::on_cmdsub default hook
brush-core/src/interp.rs	ExecutionParameters.nash_redirects accumulator; setup_redirect records file (>,>>,<,2>,&>,<>), heredoc, and here-string redirects
brush-core/src/commands.rs	gate wrapper drains nash_redirects into ExecStart for post-run read-back
brush-core/src/expansion.rs	command-substitution arm calls gate().on_cmdsub with the trimmed output
brush-core/src/gate.rs	pipe tap (docs/NASH.md §5.3): PipeEvent + Gate::on_pipe default hook + is_active()/next_pipeline_id() gating
brush-core/src/interp.rs	spawn_pipeline_processes interposes a tee on each a | b link when observation is active (nash_spawn_pipe_tee): a copier thread mirrors a bounded prefix, preserving backpressure and SIGPIPE, reports before closing the write end. No tee on the unobserved fast path.

Verification (this container): brush compat suite 2067 ran: 1684 succeeded, 6 failed, 377 known to fail, 38 skipped — the 6 failures are identical to a pristine brush-shell-v0.4.0 baseline run (environmental: ANSI-C quote and echo -e oracle differences, syntax-error formatting, missing hexdump), i.e. zero fork-caused regressions; +3 successes vs baseline are the repaired IFS tests. nash corpus: 94/94.

Planned (M3, per docs/NASH.md / NAROS.md): image-side delivery — nash baked and forced on every Linux surface via narOS. No further brush-core patches expected for M3; enforcement (Hold/Deny verdicts) remains post-M6.

Updating: diff against the upstream tag, re-vendor, re-apply // nash: patches (grep for the marker), then re-run shell/corpus/replay.py and the brush compat suite (cargo test -p brush-shell --test brush-compat-tests).