# Session handoff — 2026-05-19 (19)

Nineteenth handover. A focused **implementation run** that
**finished ADR-0027** and then **fixed two manual-testing
bugs**. The §4 "known follow-ups" from handoff-18 are all
done: ADR-0027's §2 always specified that "highlighting and
the hint panel read the individual diagnostics" — handoff-18
shipped the indicator and the model but left that wiring as a
follow-up. It is now wired. Two unrelated bugs the user found
mid-run (§2) are also fixed.

**Headline: the diagnostics are visible where they happen.**
An unknown table / column (ERROR) and a dubious comparison
(WARNING — type mismatch, `= NULL`, and now `LIKE` on a
numeric column) are overlaid on the input field *globally*
and explained in the hint panel — not just summarised by the
`[ERR]` / `[WRN]` indicator.

## State at handoff

**Branch:** `main`. Working tree clean. **10 commits** since
handoff-18 (`39b92a7`), all local — push asynchronously, not
blocking.

```
<this file>  docs: handoff 19 update — both manual-testing bugs fixed
3a40ae2 runtime: don't record an unmodified temp as the --resume target
f239ca5 walker: keep optional trailing flags completable after `--`
0e5f226 docs: handoff 19 — ADR-0027 highlight/hint wiring finished
c1c9f6c runtime: extract the indicator debounce into a tested state machine
400fb71 ui: surface diagnostics in the ambient hint panel (ADR-0027 §2)
bbfb70c ui: overlay diagnostic spans on the input field (ADR-0027 §2)
437b2f2 walker: flag LIKE on a numeric column (ADR-0027 Amendment 1)
3912fb5 walker: precise per-literal spans for expression WARNINGs
426e801 command: Operand carries a source span
```

**Tests:** **1131 passing, 0 failing, 1 ignored** (`cargo
test` — up from 1100 at handoff-18). The ignored test is the
long-standing `` ```ignore `` doc-test in
`src/friendly/mod.rs`. Typing-surface matrix: **161 cells**,
unchanged (one cell's *input* was corrected — see §3).

**Clippy:** clean (`cargo clippy --all-targets -- -D
warnings`, nursery group).

## §1. What this run did — the three §4 follow-ups

handoff-18 §4 listed three "known follow-ups (none blocking)".
The user reviewed them, judged §4-item-1 to be unfinished
ADR-0027 *scope* (the §2 Decision text, not an optional
extra), and asked for **all three** — including the small ADR
amendment item 3 needs. All three are done.

### Item 1 — diagnostic highlight + hint wiring

§2 of ADR-0027: the indicator is the *summary*; highlighting
and the hint panel carry the *where* and *why*. Built across
four commits:

- **`Operand` carries a source span** (`426e801`). Each
  WHERE-expression operand now records the byte range of the
  terminal it was built from. `Operand`'s `PartialEq` is
  hand-written to **ignore** the span — it is editor
  metadata — so `Command` equality stays whitespace- and
  position-independent and the large `Expr` test corpus
  needed no assertion changes.
- **Precise per-literal WARNING spans** (`3912fb5`). The old
  WARNING span was coarse — the whole WHERE clause.
  `predicate_warnings` now anchors each WARNING to exactly
  the offending literal operand; `where_clause_span` is
  gone.
- **Highlight overlay** (`bbfb70c`). `render_input_runs`
  overlays the walker's schema-aware diagnostics: ERROR in
  the error colour, WARNING in `theme.warning`. New
  `overlay_span` covers a token's whole byte range (the
  older `overlay_error` hit only the run at a single byte).
  The overlay is **global** — every flagged token is
  coloured wherever it sits, not just under the cursor,
  which is exactly the gap §Context described. The
  pre-existing cursor-local invalid-identifier overlay is
  kept (it covers in-progress idents, which produce no
  diagnostics); the two are additive and idempotent.
- **Hint panel** (`400fb71`). `ambient_hint` surfaces a
  diagnostic's message. `walker::input_diagnostics` is
  non-empty *only* for a command that structurally parses,
  so a non-empty result means "complete and submittable,
  but wrong" — checked early, ahead of slot hints and
  completions, so a flawed-but-parsing command no longer
  shows the misleading "Submit with Enter". The diagnostic
  under the cursor wins, else the most severe.

### Item 2 — debounce test coverage (`c1c9f6c`)

The indicator debounce was two locals in the event loop with
no unit coverage. The decision logic is now the
`IndicatorDebounce` state machine in `runtime` — `note_event`
/ `settle` / `is_armed` / `visible`, 7 unit tests for the
keystroke / settle cycle (including: a background event
mid-typing must not cancel the owed recompute). No behaviour
change; the `tokio` timer and terminal stay in the loop. A
PTY-tier test of the *actual timing* remains the one
integration-level gap (consistent with ADR-0008's four-tier
strategy).

### Item 3 — `LIKE` on a numeric column (`437b2f2`)

A genuinely new WARNING trigger, so it needed an ADR change:
**ADR-0027 Amendment 1**. `LIKE` is a text-pattern match;
against an `int` / `real` / `decimal` / `serial` column it
runs but is almost never intended. New `Type::is_numeric`,
catalog key `diagnostic.like_numeric`. Scope is deliberately
numeric-only — `bool` and the text-/blob-backed types are
not flagged; rationale is in the amendment. `docs/adr/
README.md` updated per the index-upkeep rule.

## §2. Two manual-testing bugs — both fixed

Mid-run the user reported two bugs from manual testing and
deferred the fixes; both are now done (commits `f239ca5`,
`3a40ae2`). They are unrelated to ADR-0027.

1. **`add 1:n relationship` — optional flag not completable
   after `--` (`f239ca5`).** Typing `add 1:n relationship
   from X.a to Y.b --` to start `--create-fk` made completion
   go **empty**: the trailing `--` turns the parse into a
   trailing-junk `Mismatch`, and the Mismatch arm of the
   completion expected-set resolution returned only
   `[EndOfInput]` — the skipped optional-flag expectations,
   carried in `tail_expected`, were dropped.
   `completion_probe` and `expected_at_input` now merge
   `tail_expected` into a Mismatch's expected set; the fix
   covers the whole optional-trailing-flag class
   (`--create-fk`, `--cascade`, `--force-conversion` /
   `--dont-convert`). This *also* resolved the "wrong usage
   hint" symptom: with `--create-fk` offered as a candidate
   the hint panel shows candidates, not the parse-error
   usage block. The audit (the user's requested scan) found
   `usage_key_for_input` **correct** for every multi-form
   command — `add` / `drop` / `show`, including the digit-led
   `add 1:n relationship` — so the "shows `add column`"
   symptom was not a code bug in the current tree; it is now
   regression-locked. *(The `[ERR]` on the non-existent
   column is the schema-existence diagnostic working — left
   intact.)*
2. **`--resume` recorded an unpersisted temp (`3a40ae2`).**
   An empty temp is created on launch but auto-deleted on
   quit while still empty (ADR-0015); the unconditional
   startup `write_last_project` recorded its path anyway, so
   a later `--resume` resolved to a deleted directory. All
   three resume-pointer writes are now gated on
   `!project.is_unmodified_temp()` (startup, on-switch, and a
   new on-quit write — the quit write is where a launch-temp
   the user *filled with content* finally gets remembered).
   The "no previous project" friendly error the user asked
   for already existed (`project.resume_no_previous`) —
   verified, no change needed.

## §3. Architectural delta (vs. handoff-18)

### Command AST

- `Operand` is now a struct-variant enum —
  `Column { name, span }` / `Literal { value, span }` —
  carrying a byte `span`. **`PartialEq` is hand-written to
  ignore `span`** (see the type docs); `Eq` still derived.
  `Operand::span()` accessor; `Operand::NO_SPAN` for
  programmatically-built operands (`RowFilter::eq`).

### Walker

- `walker::input_diagnostics(source, schema) -> Vec<Diagnostic>`
  — the sibling of `input_verdict`; the shared entry point
  for the highlight overlay and the hint panel.
- `predicate_warnings` emits per-literal spans;
  `pair_type_mismatch` returns `(message, span)`;
  `where_clause_span` removed.
- `like_numeric_warning` — the `LIKE`-on-numeric WARNING
  (Amendment 1). `Predicate::Like` is no longer a no-op arm.

### ui / input_render

- `render_input_runs` overlays diagnostics (`overlay_span`,
  new). `ambient_hint` has a diagnostic branch right after
  the Tab-cycle memo; `pick_hint_diagnostic` chooses
  cursor-local, else most-severe.

### runtime

- `IndicatorDebounce` state machine replaces the
  `indicator_pending` local; `app.input_indicator` mirrors
  its `visible` for the renderer.

### Types / catalog

- `Type::is_numeric()`. New catalog key
  `diagnostic.like_numeric` (+ `friendly::keys` registry
  entry).

## §4. Docs touched

- **ADR-0027** — new "Follow-up" section (the §2 wiring
  completed) and "Amendment 1" (`LIKE` on a numeric column);
  the three stale "As-built notes" bullets updated to point
  at them.
- `docs/adr/README.md` — ADR-0027 line notes Amendment 1.
- `docs/requirements.md` — test baseline (→ 1125) and the
  `S6` entry note the completed wiring + amendment.

## §5. What's next

1. **ADR-0028 — query plans (`explain`).** The last
   unimplemented member of the handoff-16 design trio;
   **Accepted**, not started. `show data … where` is the
   filtered query whose plan flips between a full scan and
   an index search. The diagnostics model and the
   `OutputLine` span-styling ADR-0028 describes are both
   easier to reach now.
2. The §2 bugs are **done** — nothing pending there.

Other open clusters unchanged from handoff-16/17/18
(snapshot/undo `U`-series; constraints `C3`; `C4` m:n;
`C3a`; `C1` table rename; `H1`; `SD1`; `TT5` CI; `V4`; `I1`;
`TU1`). Prioritisation is a user product decision — ask.

## §6. How to take over

1. **Read this file, then handoff-18** (ADR-0026/0027
   implementation), then handoff-17 / handoff-16 as needed.
2. **Read `CLAUDE.md`** — working-style rules.
3. **Read `docs/adr/0027-input-validity-indicator.md`** —
   especially the new "Follow-up" and "Amendment 1"
   sections.
4. **Run `cargo test`** — 1131 passing, 0 failing, 1 ignored.
5. **Run `cargo clippy --all-targets -- -D warnings`** — clean.
6. **Pick the next work from §5** — ADR-0028 is the natural
   pick (the §2 manual-testing bugs are already fixed);
   prioritisation is a user decision, so ask.

### Note on the typing-surface matrix

`tests/typing_surface/` is **161 cells**, unchanged. One
cell — `where_expression::complex_and_or_expression_parses`
— used a column (`t`) that does not exist in its schema; the
new schema-existence diagnostic correctly flagged it, which
revealed the cell was not testing what it claimed. Its input
was corrected to a real column and the snapshot regenerated.
The matrix-snapshot discipline from handoff-17/18 still
applies: a failing cell with *correct* new behaviour →
update its snapshot; with *wrong* behaviour → the cell
earned its keep.
