schema propose --incremental emits create_stem for an already governed empty-inference tree

[pablontiv]

Description

rootline schema propose --incremental emits a bootstrap-flat / create_stem proposal targeting an already-existing root .stem when the scanned records produce no inferred schema fields. The fixture is governed by a valid version-2 root schema, and every record validates cleanly before proposal generation.

Classification: CLI DEFECT

The documented claim is:

--incremental: skips proposals covered by existing .stem files

Source: .claude/skills/rootline/ref-schema.md:149.

Steps to Reproduce

Reconstruct a clean fixture that reaches real schema resolution and validation:

fixture="$(mktemp -d)"
cat >"$fixture/.stem" <<'YAML'
version: 2
root: true
scope:
  match: "*.md"
schema:
  kind:
    type: enum
    required: false
    values: [note, memo]
YAML
printf '# Alpha\n\nBody only.\n' >"$fixture/a.md"
printf '# Beta\n\nBody only.\n' >"$fixture/b.md"

rootline describe "$fixture" --field schema.kind -o json
rootline validate --all "$fixture" -o json
rootline schema propose --incremental "$fixture" -o json

The describe command proves the existing .stem is resolved as a version-2 schema field:

{"required":false,"severity":"error","source":"<fixture>/.stem","type":"enum","values":["note","memo"]}

Validation reaches the governed records and succeeds:

{"version":2,"kind":"rootline/validate-batch","results":[{"version":1,"kind":"rootline/validate","path":"a.md","valid":true,"errors":[],"warnings":[]},{"version":1,"kind":"rootline/validate","path":"b.md","valid":true,"errors":[],"warnings":[]}],"structural":[],"stem_health":[],"drift_warnings":[],"notices":[],"summary":{"total":2,"valid":2,"invalid":0,"errors_count":0,"warnings_count":0,"drift_warnings_count":0,"structural_errors_count":0,"structural_warnings_count":0,"stem_health_errors_count":0,"stem_health_warnings_count":0,"stem_health_info_count":0}}

The incremental proposal still targets the existing .stem:

{"version":1,"kind":"rootline/schema-proposals","path":"<fixture>","root":"<fixture>","incremental":true,"proposals":[{"id":"bootstrap-flat","operation":"create_stem","target":"<fixture>/.stem","confidence":0.85,"requires_agent":false,"patch":"version: 2\nscope:\n  match: \"*.md\"\nschema:\n","patch_preview":"version: 2\nscope:\n  match: \"*.md\"\nschema:\n"}],"summary":{"total":1,"requires_agent":0,"engine_resolved":1}}

Expected Behavior

proposals is empty or null and summary.total is 0. The records are already governed by the existing valid root .stem, and the generated schema contains no uncovered inferred fields.

Actual Behavior

The command reports one create_stem proposal targeting the .stem that already governs the records. The operation is not applicable without forcing replacement of that existing file.

Why This Matters

Incremental mode cannot be used as a reliable no-op check for already-governed body-only records. Automation sees actionable schema drift where none exists, and the emitted operation targets an existing governance file rather than representing an uncovered inference.

Related Source Evidence

• cmd/rootline/schema.go:99-103 and cmd/rootline/schema.go:125-126 expose the same incremental coverage contract in CLI help.
• cmd/rootline/schema.go:583-603 appends bootstrap-flat/create_stem before incremental filtering.
• cmd/rootline/schema.go:605-617 only runs coverage filtering when schemaToInferences returns at least one inference, so an empty generated schema leaves the pre-appended proposal intact.
• cmd/rootline/schema.go:622-647 converts an empty generated schema into an empty inference slice.
• cmd/rootline/schema_test.go:80-142 covers non-empty inferred fields but does not exercise the zero-inference branch.

Related Work

• schema apply create_stem destroys an existing .stem and reports a green validation summary #59 concerns destructive behavior in schema apply, not redundant proposal generation.
• Schema-boundary discovery is incoherent across paths and commands #65 concerns schema-boundary discovery across paths and commands, not incremental coverage filtering.

Neither issue covers this symptom.

Environment

• Rootline version: rootline version 9.12.1
• OS: macOS
• Go version: Not applicable, reproduced with the released binary

[pablontiv]

[rootline-team/investigador] 2026-09-05T14:49:17Z

Revalidated against master 8c46f8dc6f588520ce0c61bd361c089f3b4616a0 using a freshly built rootline version dev binary, Go 1.27.1 on Linux/amd64. Binary SHA-256: 7a3cc6356299f1a91ae8e307a4ac3855f08782c16286a9450b0f217b17ddd72e. Fixtures were outside the repository and did not use Git. This is executed CLI evidence, not a QA approval of a future PR.

[rootline-team] Estado: ready-for-agent

Reproduction and current cause

The original issue's two body-only records and valid root .stem still reproduce:

• describe <fixture> --field schema.kind: exit 0; resolves the optional enum [note, memo].
• validate --all <fixture> --field summary: exit 0; total=2, valid=2, all error/warning counts=0.
• schema propose --incremental <fixture>: exit 0, summary.total=1, operation=create_stem, id=bootstrap-flat, target=the already-existing .stem, patch contains an empty schema:.
• The existing .stem was byte-identical after the run.

Current source: generateSchemaProposals appends the bootstrap proposal before incremental filtering; lines 1010–1022 only enter the covered-inference filtering branch when schemaToInferences returns at least one inference. This leaves the pre-appended proposal untouched for zero inferred fields.

Control: the same two records in a directory with no .stem also emit one bootstrap proposal today. Preserve that existing bootstrap behavior; an unconditional “zero inferences => no proposal” would broaden this fix and suppress a distinct workflow.

Acceptance criteria

• The already-governed empty-inference fixture emits no proposals and summary.total=0 in incremental mode.
• Existing schema bytes, timestamps and document bytes remain unchanged.
• Add a regression test that reaches real resolution/validation and specifically exercises the zero-inference branch.
• Preserve no-stem bootstrap behavior and existing covered/uncovered non-empty inference behavior, including per-scope resolution.
• Preserve report kind/version, summary consistency, and non-incremental behavior.

Scope: incremental proposal eligibility only; no changes to schema apply, governance semantics, filesystem abstractions or write safety.

Handoff

Priority: first of the three ready bugs (#145 → #171 → #143), because false actionable proposals disrupt incremental automation. No open native blockers, assignees, linked implementation PRs or team branches were found. The original issue remains the canonical ticket; no duplicate created.

Executed existing tests:
go test ./cmd/rootline -run 'TestQueryOutputJSONLColumnOrder|TestSchemaProposeIncremental|TestRenderRepairTable' -count=1 — PASS. These tests passing does not cover this reproduced defect. Full lint, coverage and race gates were not run in this investigation and remain required for implementation.

[pablontiv]

[rootline-team/desarrollador] 2026-09-05T19:27:10Z

[rootline-team] Estado: PR abierto; implementación completa, pendiente de QA

Trabajo retomado y publicado en la rama rootline-team/issue-145, actualizada desde master e223d051f04b881aca019abcf1d3c3da15ebee1a.

PR borrador: #224
SHA para QA: 2e5e7592e978288b65445a5050f8baeceb747c83

Implementación mínima:

• añade primero la regresión del árbol gobernado con cero inferencias;
• suprime únicamente el bootstrap incremental vacío cuando existe un esquema efectivo;
• conserva el bootstrap sin .stem y el comportamiento no incremental.

Verificación ejecutada: just check, just test, just coverage-check (90.0% total), pruebas de instalador POSIX, validación de 126/126 registros del roadmap, gitleaks y ejecución real del CLI con hashes/mtimes sin cambios. PowerShell no estaba disponible localmente y se omitió; los instaladores no fueron modificados.

El PR contiene instrucciones reproducibles y está listo para el QA independiente. No se abrirá otro PR del equipo mientras éste siga activo.