Add set -o name alphabet matrix (mix bash_fixtures.gen seto)

[davydog187]

Implements #70 item 2 for the set -o / +o name alphabet only: a generated seto_matrix suite in the same generate / record / test path as date_matrix, printf_matrix, test_matrix, varop_matrix, and flags_matrix.

This is not the short-option cluster (-euo), set -o with no name (that lists every option), the item-3 filesystem-shape × command cube, Oils activation, or CI topology. It does not implement missing options.

What was enumerated

mix bash_fixtures.gen seto writes 60 cases (13 POSIX names + 14 bash extras + 3 unknown names) × { -o, +o }. Completeness is JustBash.Commands.Set.option_names/0 (errexit, nounset, pipefail): a newly implemented name that is not in the POSIX/bash alphabet fails generation, and every such name is generated unmarked.

• POSIX: allexport errexit ignoreeof monitor noclobber noglob noexec nolog notify nounset verbose vi xtrace
• Bash extras: braceexpand emacs errtrace functrace hashall histexpand history interactive-comments keyword onecmd physical pipefail posix privileged
• Unknown (bash itself refuses): not-an-option jb-not-an-option ERREXIT (case trap)
• Scripts are LC_ALL=C LANG=C set ±o 'name'; echo rc=$? so a wrong exit code is a stdout difference too. Names are quoted so a future unknown stays data.

mix bash_fixtures.gen seto --dry-run reports seto_matrix: 60 cases. mix bash_fixtures.gen now generates date, printf, test, varop, flags, and seto.

Recording

Docker was not available on the agent VM. Oracle output was recorded with the same test/fixtures/runner.sh the Docker task runs, under GNU bash 5.2.21 / Ubuntu 24.04 (uid ubuntu, not root), then pretty-printed through Mix.Tasks.BashFixtures.write_json!/2:

mix bash_fixtures.gen seto
bash test/fixtures/runner.sh < test/fixtures/bash_cases/seto_matrix.json > /tmp/seto_matrix_raw.json
# then Jason-pretty-print + Fixtures.validate, as `mix bash_fixtures` does

To re-record through Docker when it is available:

mix bash_fixtures seto_matrix

Known gaps (54 of 60)

No cell was omitted. Divergences are opts.known_gap (excluded from the digest). The fixture runner still executes them with the assertion inverted.

6 cells match bash unmarked: errexit, nounset, pipefail (both -o and +o).

Count	Reason
48	JustBash rejects a real POSIX/bash name; bash accepts it
6	Unknown name: JustBash wording/order differs and rc=1; bash exits 2

JustBash.exec/2 did not raise on any cell. No missing set -o options were implemented in this PR — it is the enumeration + harness.

Cheap follow-ups the matrix now makes un-skippable

• Accept (or implement) the remaining POSIX names agents actually write: noglob, noclobber, allexport, xtrace/verbose
• Align unknown-name refusal with bash (name: invalid option name, exit 2)
• set -o / +o with no name still lists (or dumps set commands); out of this alphabet

Not in this PR: sort -k / cut / od / xxd alphabets, the item-3 FS-shape × command cube, Oils activation, CI topology changes.

Tests

All local quality gates passed:

• mix compile --warnings-as-errors
• mix format --check-formatted
• mix credo --strict (only the existing intentional banned_fixture_apply finding)
• mix dialyzer (zero new errors; 13 skipped, same as main)
• mix test — 2 doctests, 62 properties, 6877 tests, 0 failures
• mix test --only suite:seto_matrix — 60 tests, 0 failures
• mix bash_fixtures.gen seto --dry-run — seto_matrix: 60 cases
• mix bash_fixtures.verify seto_matrix — suite sound

Related Issues

Related to #70 (item 2, set -o name alphabet only; not closing the issue)

Type of Change

• New feature (non-breaking change which adds functionality)

Testing

• Added new tests
• All existing tests pass
• Tested manually (mix bash_fixtures.gen seto --dry-run, local runner.sh recording, JustBash vs oracle classification)

Checklist

• My code follows the style guidelines of this project
• I have run mix format
• I have run mix credo and addressed any issues
• I have added tests that prove my fix is effective or that my feature works
• New and existing tests pass locally with my changes
• I have updated the documentation accordingly
• I have updated the CHANGELOG.md (for non-trivial changes)