# Session handoff — 2026-05-26 (43)

Forty-third handover. This session started from "let's handle the F1–F3
follow-ups" (handoff-42 §3) and ended up going much deeper: it shipped the
F1–F3 work and the carried message-gap follow-ups, then — driven by the
user's questions — opened, drafted, `/runda`'d, **reframed**, and began
**implementing a new ADR (0036)** about value handling in advanced-mode
SQL DML. **ADR-0036 Phase 1 is implemented.** Phases 2–3 and several
tracked items remain — hence the handoff.

## §1. State at handoff

**Branch:** `main`. **HEAD `1d5534b`.** **Tests: 1930 passing, 0 failing,
0 skipped, 1 ignored** (the `friendly/mod.rs` ` ```ignore ` doctest).
**Clippy:** clean (`cargo clippy --all-targets -- -D warnings`).

**Unpushed commits from this session (newest first; all normal — push is
the user's step, never prompt about it):**

```
1d5534b feat: ADR-0036 Phase 1 — validate advanced-mode INSERT literals + show the value
dc9a475 docs: ADR-0036 revised to surgical "validate-and-retain"; +X4/X5 open questions
3e3a2fb docs: ADR-0036 (Proposed) — bind literal DML values, verbatim text only for expressions/queries
f8a91f4 feat: ADR-0035 Amendment 1 follow-up — enrich replay errors + close message gaps
cb8ff8a feat: ADR-0035 Amendment 1 — drop composite UNIQUE; friendlier drop-column + generic-error wording
```

(Plus the handoff-42 unpushed set below them. All unpushed; normal.)

## §2. What shipped

### ADR-0035 Amendment 1 + follow-ups (commits `cb8ff8a`, `f8a91f4`)

The whole-Phase-4 `/runda` follow-ups F1–F3, then the broader F2 + gaps
B/C/D:

- **F3** — drop a composite UNIQUE via a **derived, engine-neutral name**
  `unique_<cols>` (recomputed live, nothing persisted), reusing the
  existing `DROP CONSTRAINT <name>` grammar. Ambiguous names refused. One
  undo step. `describe` annotates each UNIQUE (`unique_a_b: unique (a, b)`).
  ADR-0035 **Amendment 1**.
- **F1** — dropping a column a composite UNIQUE covers is refused up-front
  with the derived name + the drop command.
- **F2** — generic-error `{table}` leak fixed (`error.generic.hint_no_table`);
  then **F2-broad**: replay failures now enrich via `enrich_dsl_failure` +
  the shared `App::translate_context_for`, and the `ctx_*` fallbacks became
  neutral prose (no raw `{name}` anywhere).
- **Gap C** — SQL `ALTER … ADD FOREIGN KEY` on a missing child column no
  longer suggests the DSL-only `--create-fk`.
- **Gap B** — dropping a single-column-UNIQUE column refuses pointing at
  `drop constraint unique from T.col`.
- **Gap D** — the 4e CHECK-guard + 4f change-type-FK refusals reworded to
  explain *why* (wording only; `static_refusal` left as-is).

### ADR-0036 — value validation for advanced-mode DML (commits `3e3a2fb`, `dc9a475`, `1d5534b`)

This is the session's main arc, and the next session should read
**`docs/adr/0036-typed-dml-values-vs-verbatim.md`** in full. The short
version:

- **The finding.** Advanced-mode SQL `INSERT`/`UPDATE` hands literal data
  values to the engine as text, so it gets **none** of the DSL's value
  feedback — no type validation (a malformed `date` `2025/01/15` is
  silently stored), and the offending value can't appear in errors. The
  DSL never did this: `do_insert` parses each value, validates it
  (`bind_for_column` → `validate_date`/`shortid::validate`), and **binds**
  it as a parameter. Proven by a characterization test.
- **The arc.** First instinct was to *consolidate* (bind literals via the
  DSL path, even emit `Command::Insert` from the advanced surface). The
  user pushed back on fusing the modes, and a concrete **auto-fill
  difference** (simple-mode fills an omitted non-PK `serial` with
  `MAX+1`; advanced-mode does not) confirmed the modes are **not**
  identical even for single-row literals. So the ADR was **reframed**
  (commit `dc9a475`) to the **surgical** principle:

  > **Validate the literal values (sharing the per-type validators) and
  > retain them for error reporting; execute verbatim, and keep auto-fill,
  > execution, and command identity mode-specific.** Share a *mechanic*,
  > not a *command* (`requirements.md` X5). It **augments** (does not
  > supersede) ADR-0030 §4 / ADR-0033 §10; ADR-0033 **Amendment 3 stands**.

- **Phase 1 (implemented, `1d5534b`).** `build_sql_insert` captures each
  `VALUES` position from the matched path (`Some(Value)` for a literal incl.
  signed numbers; `None` for an expression) onto a new `literal_rows` field
  on `Command::SqlInsert` — **no grammar change, no reparse**.
  `do_sql_insert` validates those literals against their column types
  (reusing `impl_value_for`) **before** the still-verbatim insert.
  `user_value_for_column` reads `literal_rows` so a constraint error shows
  the real value. Runtime uses `run_sql_insert_with_literals`; the 6-arg
  `run_sql_insert` is the no-capture raw entry (kept so worker-level tests
  didn't churn).

## §3. What's next (ADR-0036 Phases 2–3 — the reason for the handoff)

Read `docs/adr/0036-…md` §5 (phasing) and §6 (non-goals) first.

- **Phase 2 — `UPDATE … SET` literal validation.** Same capture-at-parse
  technique on the SET assignment list (`SqlUpdate` currently carries no
  captured literals — it would gain a `literal_rows`-equivalent). Validate
  `SET col = <literal>`; skip `SET col = <expr>` and `WHERE` (deliberately
  text). Mirror Phase 1's structure.
- **Phase 3 — completion hinting / highlighting.** The **only** part that
  needs a grammar change: `Choice(typed-literal-slot, sql_expr)` at each
  value position, reusing the DSL's live `column_value_list` /
  `TypedValueSlot`s (`src/dsl/grammar/data.rs:141`/`189`/`269`,
  `shared.rs`). When it lands it supersedes only Phase 1's literal
  *detection* (the validation/enrichment on top is permanent — a
  deliberate, documented small throwaway).

## §4. Tracked follow-ups (in `requirements.md` Cross-cutting)

- **X4 — serial auto-fill difference (possible bug, investigate).**
  Simple-mode `do_insert` auto-fills an omitted non-PK `serial` with
  `MAX(col)+1`; advanced-mode (`plan_shortid_autofill`) only fills
  `shortid`, never non-PK `serial`. Likely unintended. Decide whether
  advanced mode should match (probably yes) and align ADR-0018. **Untouched
  by ADR-0036** (which is surgical).
- **X5 — framework cohesion / restructuring (strategic).** The
  grammar/execution framework (lexer → walker `Node`s → grammar tree →
  `Command`s → executors) grew organically and was never specified as a
  whole; commands are coupled to execution, which tempts command-reuse to
  get execution-reuse. Desired: **unique commands per unique case; share
  execution mechanics as helpers, never by fusing identity.** A
  *descriptive* ADR (map what exists + the reuse-boundary rule) is likely
  the cheaper first step before any restructure. Not scheduled.

### Minor / deferred from ADR-0036 Phase 1

- **Natural-order error-value *display* deferred.** Validation works for a
  no-column-list insert (maps positions to schema columns), but
  `user_value_for_column` only resolves the offending value for the
  **explicit column-list** case; natural-order falls back to the neutral
  "that value". Small follow-up (the `_with_schema` enricher could resolve
  it).

## §5. Carried follow-ups (still open from handoff-42 §3/§4)

- **F2-narrow vs broad:** done (broad shipped). 
- Composite-UNIQUE F3 message wording — the `describe` shows
  `unique_a_b: unique (a, b)` (lowercased to match sibling lines); the user
  saw `UNIQUE` in the preview but accepted the rendered form. If they want
  uppercase or a bracket form, it's a one-line tweak in `output_render.rs`.
- The handoff-39 §8 long-tail items (app-lifecycle runtime-failure
  journalling; M4 execution-time mode side-channel; `blob` value literal —
  which ADR-0036 notes belongs in the literal layer; CI/TT5; DSL→SQL
  teaching echo, ADR-0030 Phase 5) remain.

## §6. Process pins (unchanged, and reinforced this session)

- **Confirm every commit** (propose message, wait). No AI attribution.
  **Push is the user's step.** Unpushed commits are normal.
- **`/runda` at planning exit earns its keep.** This session's `/runda` on
  ADR-0036 caught a misattributed citation, an overstated matrix, and three
  unsettled boundary forks — *before* any code.
- **Escalate design forks; don't consolidate by reflex.** The ADR-0036 arc
  is the cautionary tale: the clean-looking "emit `Command::Insert`" idea
  would have silently changed auto-fill semantics. The user's "keep the
  modes apart" instinct was right; the resolution was to share *one
  mechanic* (validators), not the command. Default to a distinct command
  per case (X5).
- **Keep docs lockstep** — ADR + README index + forward-notes +
  `requirements.md` in the same change.

## §7. How to take over

1. **Read, in order:** this file → `CLAUDE.md` →
   `docs/adr/0036-typed-dml-values-vs-verbatim.md` (the full arc + the
   surgical principle + phasing) → `docs/requirements.md` X4/X5.
2. **Baseline:** `cargo test` (1930 / 0 / 0 / 1 ignored) + `cargo clippy
   --all-targets -- -D warnings` (clean).
3. Pick up **ADR-0036 Phase 2** (`UPDATE … SET` literal validation,
   mirroring Phase 1), or take a tracked item (X4 the most concrete bug),
   with the user. Phase 1's shape (`src/dsl/grammar/data.rs`
   `capture_literal_rows` + `do_sql_insert` validation + `runtime.rs`
   `user_value_for_column`) is the template to follow.
