# Architecture Decision Records

This directory contains the project's ADRs, recorded per
[ADR-0000](0000-record-architecture-decisions.md).

## Index

- [ADR-0000 — Record architecture decisions](0000-record-architecture-decisions.md)
- [ADR-0001 — Language and TUI framework](0001-language-and-tui-framework.md)
- [ADR-0002 — Database engine](0002-database-engine.md)
- [ADR-0003 — Input modes and command dispatch](0003-input-modes-and-command-dispatch.md)
- [ADR-0004 — Project file format](0004-project-file-format.md)
- [ADR-0005 — Column type vocabulary](0005-column-type-vocabulary.md)
- [ADR-0006 — Undo snapshots and replay log](0006-undo-snapshots-and-replay-log.md) — **Accepted**. The **replay/journal half** (U3/U4) shipped via ADR-0034; the **undo/snapshot half** (U1/U2) is settled by **Amendment 1 (2026-05-24)** and **implemented 2026-05-24** (plan: `docs/plans/20260524-adr-0006-undo-snapshots.md`; ring in `src/undo.rs`, worker hook in `src/db.rs`). Amendment 1 **supersedes the original "snapshots only before destructive operations" model**: a snapshot is taken before **every** data/schema mutation (DSL + SQL) for familiar single-step (Ctrl-Z) undo — so the confirmation collapses to *naming the one command being undone* (no db-diff). Snapshot is a **hybrid whole-project copy** — database via the online backup API **plus** `project.yaml`/`data/*.csv` as files — reconciling this ADR with ADR-0015's "text is authoritative, db is derived"; undo restores all three directly. Staged before the mutation's transaction, finalised after the db commit (preserves ADR-0015 §6 commit-db-last); rolled-back ops leave no snapshot. **Persisted** ring under `.snapshots/`, **N = 50** (raised from 10), git-ignored + export-excluded + temp-cleanup-aware. `redo` supported, **redo stack discarded on new work**. **Batch ops record one undo step** (`replay` + future batch via a Begin/EndBatch worker primitive); **`import` is outside undo** (it switches projects per ADR-0015 §11, leaving the current project untouched). A **`--no-undo` CLI flag** disables snapshotting (hardware escape hatch). Adds the `backup` feature to `rusqlite`
- [ADR-0007 — Sharing and export](0007-sharing-and-export.md)
- [ADR-0008 — Testing approach](0008-testing-approach.md)
- [ADR-0009 — DSL command syntax conventions](0009-dsl-command-syntax-conventions.md)
- [ADR-0010 — Database access via a dedicated worker thread](0010-database-access-via-worker-thread.md)
- [ADR-0011 — Foreign-key column type compatibility](0011-fk-column-type-compatibility.md)
- [ADR-0012 — Internal metadata for user-facing column types](0012-internal-metadata-for-user-facing-types.md)
- [ADR-0013 — Relationships, naming, and the rebuild-table strategy](0013-relationships-and-rebuild-table.md)
- [ADR-0014 — Data operations, value literals, and the auto-show pattern](0014-data-operations-and-value-model.md)
- [ADR-0015 — Project storage runtime](0015-project-storage-runtime.md)
- [ADR-0016 — Pretty table rendering for data and structure views](0016-pretty-table-rendering.md)
- [ADR-0017 — Column type-change compatibility](0017-column-type-change-compatibility.md)
- [ADR-0018 — Auto-fill contracts for `serial` and `shortid` columns](0018-auto-fill-contracts-for-serial-and-shortid.md)
- [ADR-0019 — Friendly error layer (H1) and i18n message catalog](0019-friendly-error-layer-and-i18n.md)
- [ADR-0020 — Tokenization layer for the DSL parser](0020-tokenization-layer-for-the-dsl-parser.md)
- [ADR-0021 — Parser-as-source-of-truth for H1a (per-command usage in parse errors)](0021-parser-as-source-of-truth-for-h1a.md)
- [ADR-0022 — Ambient typing assistance: colour, hint panel, completion (I3 + I4)](0022-ambient-typing-assistance.md) — **Amendment 1 supersedes §12's simple-mode-only carve-out**: the unified mode-aware walker (ADR-0030/0031/0032) now speaks SQL, so advanced-mode ambient assistance is re-enabled. `ambient_hint_in_mode` + `hint_resolution_at_input_in_mode` + `expected_for_hint_snapshot` thread `Mode`; `render_hint_panel` calls ambient for all modes (no more advanced-mode `None`); the one-shot `:` sigil is stripped before the ambient walk. Fixes a live bug where advanced-mode SQL hinting/completion-preview were dead despite Phase 2 marking them green (validated at the engine layer, not the UI). Simple-mode gating, highlighting, and the §13 performance posture are unchanged; covered by an app-level render test plus ambient-layer regression locks; **Amendment 2 reverses the handoff-14 keywords-first candidate ordering** — schema identifiers (table/column/relationship names) now sort *before* keywords so a name the user would have to look up stays visible in the single-row, window-scrolled candidate line (keywords are learned over time; the `tok_identifier`/`tok_keyword` colour split marks the boundary); shipped with a `walk_repeated` fix that surfaces a list item's trailing optionals at a clean boundary (`order by Name ` → `asc`/`desc`, `select Name ` → `as`, `create table … Code(text) ` → `not`/`unique`/`default`/`check`; the `,` separator deliberately not surfaced); records a deferred two-line hint box for growing lists; **Amendment 3 makes the ambient-hint fallback rung schema-aware** — Amendment 1's bottom-rung `parse_command_in_mode` was schemaless while every earlier rung was not, so between-values insert hints pointed at `)` (type-blind close) instead of `,` and wrong-arity closed tuples read "submit with Enter" for an input the schema-aware parse rejects (issue #2); now uses `parse_command_with_schema_in_mode`, no extra walk, with the friendly arity diagnostic still winning at its higher rung; **Amendment 4 gives column types a dedicated highlight class** — both `Node::Ident.highlight_override` *and* the `Word.highlight_override` field were dead (driver destructured the former to `_`, `walk_word` hardcoded `Keyword`); now both wired through, with a new `HighlightClass::Type` + eighth `Theme` field `tok_type` (a pink/deep-magenta distinct from both keyword purple and identifier teal) so types no longer render identically to identifiers (issue #8); the three `IdentSource::Types` slots opt in via `Some(Type)` (advanced-mode single-word SQL aliases — `float`, `varchar`, … per ADR-0035 §3 — ride along for free), and the two-word `double precision` alias opts in via the new `Word::type_keyword` constructor so it matches its synonyms; **Amendment 5 lets the hint panel grow for long prose hints** — a fixed one-row panel clipped long field-value/usage hints past the first line (issue #12); `resolve_hint_lines` now pre-wraps prose and `render_right_column` sizes the panel to the line count (1 row default, up to `MAX_HINT_ROWS`=3, reclaimed when short) with a `clamp_wrapped` ellipsis backstop; the candidate list still scrolls horizontally on one row (Amendment 2's deferred two-line candidate box stays deferred); also shortens the 299-char `parse.usage.sql_create_table` synopsis to a terse one-liner (full grammar remains in `help.ddl.sql_create_table`)
- [ADR-0023 — Unified declarative grammar tree](0023-unified-grammar-tree.md) — direction (superseded for execution detail by ADR-0024)
- [ADR-0024 — Unified grammar tree: execution plan](0024-unified-grammar-tree-execution-plan.md) — **Accepted**, the executable spec — implemented (Phases A–F; Phase F shipped "minimal", `parser.rs` retained as the router — see the ADR's Phase F implementation note)
- [ADR-0025 — Indexes](0025-indexes.md) — **Accepted** (**Amendment 1, 2026-05-25**: UNIQUE indexes admitted on the **advanced-mode** surface via `CREATE UNIQUE INDEX` — ADR-0035 §4d; the `IndexSchema.unique` flag round-trips through `project.yaml` with no new metadata table since the engine reports uniqueness natively; simple-mode `add unique index` stays deferred), `add index` / `drop index`, persistence, rebuild-table preservation, and items-list display (`C3` index portion + `S2`)
- [ADR-0026 — Complex WHERE expressions](0026-complex-where-expressions.md) — **Accepted**, stratified recursive expression grammar (`AND`/`OR`/`NOT`, comparisons, `LIKE`, `IS NULL`, `IN`, `BETWEEN`) for `update` / `delete` / `show data` filters; `show data` gains `where` + `limit`; adds the `Subgrammar` node and a recursive `Expr` AST (`C5a`)
- [ADR-0027 — Input-field validity indicator](0027-input-validity-indicator.md) — **Accepted**, a debounced `[ERR]` / `[WRN]` marker at the input row's right edge, backed by a walker diagnostics-severity model (parse-outcome + schema-existence); advisory, never blocks submission (`S6`); Amendment 1 adds a `LIKE`-on-numeric-column WARNING
- [ADR-0028 — Query plans (`EXPLAIN QUERY PLAN`)](0028-query-plans.md) — **Accepted**, an `explain` prefix command over `show data` / `update` / `delete`; an annotated, span-styled plan tree; introduces the `OutputLine` styled-runs mechanism (ADR-0016's deferred per-span styling) (`QA1` / `QA2`)
- [ADR-0029 — Column constraints (NOT NULL / UNIQUE / CHECK / DEFAULT)](0029-column-constraints.md) — **Accepted**, the four column-level constraints declared in the column-spec suffix (`create table` / `add column`) and modified on existing columns via `add constraint …` / `drop constraint …`; a pre-flight dry-run guards populated columns; `CHECK` reuses the ADR-0026 expression grammar via `Subgrammar` (`C3`)
- [ADR-0030 — Advanced mode: the standard-SQL surface](0030-advanced-mode-sql-surface.md) — **Accepted**, SQL added as grammar *within the unified grammar tree* (ADR-0024), not a separate batch parser — so SQL gets the same completion / highlighting / hints / parse-errors as the DSL; mode gates the SQL forms; DDL routes through the typed `Command` executor (metadata + type vocabulary preserved), DML and `SELECT` execute as validated SQL; engine-neutral posture, the DSL→SQL teaching echo; supersedes ADR-0001's `sqlparser-rs` reservation; phased plan (`Q1` / `Q2` / `Q4`); **§13 OOS-2 (EXPLAIN of advanced SQL) superseded by ADR-0039**
- [ADR-0031 — The SQL expression grammar](0031-sql-expression-grammar.md) — **Accepted**, the stratified SQL expression grammar fragment commissioned by ADR-0030 §3: a single precedence ladder (`OR`/`AND`/`NOT`, the comparison/`LIKE`/`IN`/`BETWEEN`/`IS NULL` predicate set, arithmetic incl. `||`, function calls, `CASE`) — the superset of ADR-0026's DSL `WHERE` grammar, authored as a parallel fragment so simple mode is untouched; pure validation, builds **no** AST (consumers run/store SQL as text per ADR-0030 §4/§6); reuses ADR-0026's `Subgrammar` recursion + depth cap unchanged; subquery expressions and qualified column refs deferred to ADR-0030 Phase 2
- [ADR-0032 — The full SQL `SELECT` grammar](0032-sql-select-grammar.md) — **Accepted**, the Phase-2 grammar commissioned by ADR-0030 §3: full `SELECT` with `INNER`/`LEFT`/`RIGHT`/`FULL OUTER`/`CROSS` joins, `GROUP BY`/`HAVING`, all four set ops (`UNION`/`UNION ALL`/`INTERSECT`/`EXCEPT`), `WITH` and `WITH RECURSIVE` CTEs, `LIMIT … OFFSET`, `DISTINCT`, `t.*`, and bare-alias projection (lifting Phase-1 §4.2); additive extensions to ADR-0031's `sql_expr` for scalar subqueries, `IN (SELECT …)`, `[NOT] EXISTS`, and qualified column refs (redeeming ADR-0031 §7 OOS-1/OOS-2); grammar-recursion via `Subgrammar(&SQL_SELECT_COMPOUND)` reuses ADR-0026's `MAX_SUBGRAMMAR_DEPTH = 64` cap unchanged; **softens ADR-0030 §8's "ambient assistance comes for free" claim**: completion scope needs new `WalkContext` accumulators (a `from_scope_stack` of `ScopeFrame`s holding `from_scope` / `cte_bindings` / `projection_aliases`), a **new walker node variant `Node::ScopedSubgrammar(&Node)`** as the push/pop trigger (existing `Node::Subgrammar` unchanged so DSL `Expr` and `sql_expr` recursion are unaffected), qualified-prefix completion narrowing, body-projection-derived CTE column resolution (so `SELECT *` and explicit-projection CTE bodies both yield real column completion past `cte_alias.|`), and a **post-walk fixup pass** that re-resolves projection-list identifier highlighting/validity once `FROM` is parsed (the projection-before-FROM problem); classifies every Phase-2 validation case against ADR-0027's ERROR/WARNING guideline (§11): five new `diagnostic.*` keys for parse-time-detectable cases (unknown qualifier, ambiguous column, projection-alias misplaced, CTE/compound arity mismatch) plus eight `engine.*` translation keys; a MatchedPath-walking predicate-warnings variant that closes the Phase-1 gap where SQL `WHERE` expressions emitted no `LIKE`-on-numeric / `= NULL` / type-mismatch warnings (ADR-0027 Amendment 1 finally extends to the SQL surface); adds a worker-side post-prepare type-resolution pass via engine column-origin metadata so bare column refs recover their playground type (partially lifting Phase-1 §4.5, the bool→0/1 case) — `Cargo.toml` gains `column_metadata` to rusqlite features (verified against pinned 0.39.0); `__rdbms_*` rejection extended to every new table-source slot; Amendment 1 narrows §12's resolution rule from a grammar-side structural classification to "trust the engine's column-origin metadata verbatim" after an empirical probe showed origin metadata follows through non-recursive CTEs, scalar subqueries, derived tables, set ops, and joins — the one structural exception is recursive CTE result columns, which return None and stay typeless; Amendment 2 records that §10.6's "rewrite the highlight class" prescription is realised via the two-pass schema-existence diagnostic + the renderer's diagnostic-overlay path (no separate per-byte rewrite step needed; no new HighlightClass variant), and that the projection-before-FROM completion narrowing has been improved by an `src/completion.rs` look-ahead probe when the leading walk's `from_scope` is empty but the full input parses
- [ADR-0033 — The full SQL DML grammar (`INSERT` / `UPDATE` / `DELETE`)](0033-sql-dml-grammar.md) — **Accepted** (implemented + verified through sub-phase 3k, 2026-05-23; phase-exit report `docs/handoff/20260523-phase-3-verification.md`), the Phase-3 grammar commissioned by ADR-0030 §3: single- and multi-row `INSERT` (incl. `INSERT … SELECT` recursing through ADR-0032's `SQL_SELECT_COMPOUND`), `UPDATE` with `SET` assignment list, `DELETE`, all three optionally followed by `RETURNING projection_list`, plus full `ON CONFLICT … DO NOTHING / DO UPDATE` UPSERT on INSERT; **fixes the DSL-vs-SQL dispatch architecture for shared entry words (`insert`/`update`/`delete`)**: SQL-first / DSL-fallback in Advanced mode via a `Choice(SQL_shape, DSL_shape)` per shape, gated by a new walker capability `Node::Guard(fn)` — a zero-byte-consumption gating node that fails the enclosing Seq with a `ValidationError`; carries `Command::SqlInsert` / `SqlUpdate` / `SqlDelete` variants and `do_sql_*` worker handlers each of which knows the target table (for re-persistence) and the `returning: bool` flag (for DataResult routing); `shortid` auto-fill mirrors the DSL `do_insert` mechanism via worker post-fill; SQL DELETE produces the same per-relationship cascade summary the DSL DELETE does (ADR-0014 parity); three new walker diagnostics (`insert_arity_mismatch` ERROR, `auto_column_overridden` WARNING, `not_null_missing` WARNING) with positive + negative tests each; OOS list explicitly carves out `DEFAULT VALUES` (the project's planned seed feature), SQLite-specific `OR REPLACE` / `OR IGNORE` / `OR ABORT` / `OR FAIL` / `OR ROLLBACK` prefixes, `UPDATE FROM` multi-table updates, and WITH-prefixed DML; the `excluded` keyword inside `ON CONFLICT DO UPDATE` is a deliberate carve-out from ADR-0030 §7's engine-neutral posture (no standard-SQL UPSERT spelling exists that SQLite and PostgreSQL share); eleven phased sub-phases each with explicit exit gates + written DA gate, opening with the dispatch mechanism before any DML grammar lands; initial DA review recorded seven critiques that were resolved before status moved to Proposed; **Amendment 1 supersedes §2's dispatch mechanism**: the originally-chosen `Node::Guard(fn)` + `Choice(SQL_shape, DSL_shape)` was found during 3a to be unworkable as framed (any guard-in-`Choice` mechanism forces a `walk_choice` change — `walk_choice` only falls through on `NoMatch`, so Simple-mode valid-DSL would wrongly surface "this is SQL", and `walk_seq` treats a `NoMatch` past `idx 0` as a hard `Failed`, breaking Advanced-mode DSL fall-through); replaced by **category-grouped, mode-aware dispatch** in `walker::walk` (each `REGISTRY` entry tagged `CommandCategory::{Simple, Advanced}`, generalising the existing whole-command `is_advanced_only` gate), shared entry words carrying a node in both groups, no `Node::Guard` and no `walk_choice`/`walk_seq` change, advanced-mode completion SQL-first with DSL as a full-line fallback; **Amendment 2 (sub-phase 3f) supersedes §7's cascade mechanism**: the WHERE-injected per-child pre-count rested on a premise that was factually wrong about the DSL handler (which detects cascades by before/after row-count diffing inside a transaction, not by `Expr`-derived pre-count subqueries) and would have broken the §2 parity promise by reporting `SET NULL` the DSL path doesn't; replaced by mirroring `do_delete`'s count-diff exactly (verbatim DELETE executes, child-count diff observes the cascade — `ON DELETE CASCADE` row removals only, SET NULL deferred for both paths to preserve parity), which shares the render-layer formatter for free via `CommandOutcome::Delete` and **withdraws risk R2** (no WHERE-byte extraction, no N+1 subquery); **Amendment 3 (sub-phase 3j) records the command-identity model and defers the execution-mode side-channel**: a command is the typed outcome of a *mode-rooted* grammar path and its identity is intrinsic (Advanced mode tries SQL first, falls back to the *Simple* DSL command when no SQL branch matches a token, e.g. `delete … --all-rows`; note `update … --all-rows` does *not* fall back — the SQL `SET` expression eats `--all-rows`, harmless since the engine treats it as a comment); **Simple mode commits the DSL candidate for shared words** so the *real* DSL error surfaces, and when that line would also run in advanced mode the rendering layer **combines** them — DSL error **plus** an `advanced_mode.also_valid_sql` pointer ("… (valid as SQL in advanced mode)") — keeping the actionable DSL fix while pointing at advanced mode; bare "this is SQL" is reserved for entry words with no DSL form (`select`/`with`); a fully-overlapping input (`insert … values …`) legitimately yields *two distinct commands* (`Command::Insert` typed-AST vs `Command::SqlInsert` validated-text) that do the same thing but execute differently (ADR-0030 §4), so each is tested in the mode that produces it; **corrects the plan's 3j exit-gate premise** that the DSL DML tests run in Simple mode (they call `parse_command`, which defaults to Advanced) — the real invariant is "Simple-mode behaviour unchanged, Advanced mode SQL-first, DSL grammar tested in Simple mode, both variants tested in their producing mode", with §6/§7 parity keeping the paths observably equivalent; and **defers to its own future ADR** the execution-time mode side-channel (three-way `Mode`: simple/advanced/advanced-one-shot threaded through `Action`→worker, for mode-dependent *output* like echoing generated SQL) — today only the *rendering* side-channel `OutputLine.mode_at_submission` exists, and the three-way distinction is not required for Phase 3 dispatch correctness; **Amendment 4, 2026-05-27** (design agreed, pending impl): **reverses Amendment 3's `update … --all-rows` counter-example as a bug** — surfaced by the ADR-0038 echo design. The walker has no `--` comment support (it lexes two minus operators) while the engine treats `--` as a comment, so `update T set x=42 --all-rows` was silently parsed as the expression `42 - -all - rows` over **non-existent columns** `all`/`rows` (an ADR-0027 "flag-if-it-will-fail" case) and matched `SqlUpdate`. Decision: the `--all-rows` sequence makes the SQL `UPDATE` shape **fail**, so dispatch **falls back to the DSL `Update { AllRows }`** — symmetry with `delete … --all-rows`; no `--` comment feature introduced (trailing comments stay unsupported). Inverts `sql_dml_e2e.rs::e2e_update_all_rows_in_advanced_does_not_fall_back_to_dsl`; mechanism settled test-first in the build; folded into the ADR-0038 effort (makes `update … --all-rows` echoable); **Amendment 5, 2026-05-28** (implemented + verified, user-confirmed): `advanced_mode.also_valid_sql` (the cross-mode pointer from Amendment 3) fires on **validity**, not just **parse** — *"valid"* meaning `input_verdict_in_mode(input, schema, Mode::Advanced) == None` in the ADR-0027 sense (parse succeeds *and* no Warning/Error diagnostic from any pass). Surfaced by **issue #1**: a positional `INSERT INTO T VALUES (…)` (no column list) with a value count that didn't match the target's column count parsed in advanced but failed at the engine, so the syntactic-only Amendment-3 gate promised a mode switch that wouldn't help. Closes the gap by (a) extending `dml_insert_arity_diagnostics` (§8.1, previously Form A only — its own doc-comment deferred Form B) to also check the no-column-list form against the schema's column count, emitting a new `diagnostic.insert_arity_mismatch_form_b` ERROR per offending tuple, and (b) refactoring `advanced_alternative_note` to read the validity verdict instead of running its own bespoke check — any static diagnostic added to the pipeline in the future automatically participates in the pointer gate. Side benefit: the `[ERR]` validity indicator now lights up at typing time for the reported scenario, no longer needing a submit to learn the line is wrong. Tests pinned: `insert_form_b_arity_mismatch_under_supply_fires` / `_over_supply_fires` / `_match_is_silent` / `_unknown_table_is_silent` (walker); `ambient_hint_omits_advanced_pointer_when_form_b_value_count_wouldnt_match` (gate); `simple_mode_submit_of_sql_construct_appends_advanced_pointer` (pointer still fires for genuine SQL-only constructs against a known schema). Amendment 3's "would parse in advanced mode" should henceforth be read as a synonym for "valid in advanced mode" in this stricter sense; the user-confirmed behavioural change is exactly the issue #1 bug case (no other input flips its pointer state)
- [ADR-0034 — `history.log` as a complete command journal; replay reads success-only](0034-history-journal-and-replay-filter.md) — **Accepted**, resolves a three-way tension in `history.log`'s roles found while implementing ADR-0033 3f: (1) the persistent log is success-only while the in-memory Up/Down recall ring records *every* submission (success or failure, "so users can recall and edit typo'd commands"), and the ring is re-seeded from the log on project open — so **failed commands are recallable within a session but silently lost across sessions**; (2) replay wants the state-building (successful) commands while recall wants everything typed, which one success-only file cannot serve; (3) `replay history.log` never actually worked — `run_replay` parses each whole line through the DSL parser with no understanding of the `<ts>|<status>|<source>` record shape, so a real log fails on line 1, and **no test ever fed the pipe format to replay** (the `replay_history_log_records_subcommands_only` test only checks what replay *writes*, never replays the log as input). Decision: `history.log` becomes a **complete journal** — every submission recorded, tagged `ok`/`err` via the status field the format already reserved (ADR-0015 §5) — and **each consumer filters**: hydration reads all records (cross-session recall matches in-session), replay reads `ok` only (and learns the journal format, while still accepting bare-command `.commands` scripts; detection by the leading timestamp+status prefix so a `|` inside a bare command isn't misread). Successful commands stay journalled transactionally by the worker; failed commands are journalled `err` best-effort from the runtime/app error path (a parse failure never reaches the worker). Amends ADR-0006's "successfully executed" wording and ADR-0015 §5 ("status always `ok`") / §12 (hydration). Code deferred to two tracked test-first sub-tasks (journal-failures+filtering; replay-parses-journal-format); existing all-`ok` logs need no migration; **implemented 2026-05-24** (plan `docs/plans/20260524-adr-0034-history-journal.md`); **Amendment 1 (2026-05-24): replay filters out app-lifecycle commands** — a working `replay history.log` (the §3 fix) exposed that the journal also records `save as`/`load`/`new`/`export`/`import`/`rebuild`/`mode` (which would panic the worker dispatch or abort the replay), so replay now re-applies **only** schema/data write commands and **skips** every `Command::App` + nested `Command::Replay`; **all skips continue** (never abort — reversing the prior nested-`replay` refusal, so a journal containing a once-run `replay` needs no hand-editing, and the infinite-loop footgun is closed by construction), with a `[skip]` **warning** on `import` and nested-`replay` skips (their omission can leave replayed state incomplete) and silent skips for the rest; `replay.error_nested` removed, `replay.skipped_import`/`replay.skipped_replay` added, `ReplayCompleted` carries `warnings`
- [ADR-0035 — Advanced-mode SQL DDL](0035-advanced-mode-sql-ddl.md) — **Accepted** (design agreed 2026-05-24; validated end-to-end by sub-phases 4a/4a.2/4a.3/4b `CREATE TABLE` (incl. foreign keys) + 4c `DROP TABLE [IF EXISTS]` + 4d `CREATE [UNIQUE] INDEX` / `DROP INDEX [IF EXISTS]` + 4e `ALTER TABLE` add/drop/rename column + 4f `ALTER TABLE … ALTER COLUMN TYPE` + 4g `ALTER TABLE` add/drop constraint + add FK + 4h `ALTER TABLE … RENAME TO` + 4i verification sweep (completion merge + simple/advanced completion colour + describe of table-level constraints + self-ref FK indicator + CREATE-TABLE help/usage), implemented 2026-05-25/26 — **Phase 4 complete**; **Amendment 1, 2026-05-26**: drop a composite UNIQUE via a derived, engine-neutral `unique_<cols>` name that reuses the existing `DROP CONSTRAINT <name>` grammar — no new syntax, no metadata, §4g anonymity intact; `describe` shows the name; dropping a UNIQUE-covered *column* now refuses with that name + the drop command), **Phase 4** of the ADR-0030 roadmap (peer of 0031/0032/0033) and **clarifies ADR-0030 §4**. Advanced-mode `CREATE`/`DROP`/`ALTER TABLE` + `CREATE`/`DROP INDEX` get their **own per-statement commands** (`SqlCreateTable`/`SqlAlterTable`/`SqlDropTable`/`SqlCreateIndex`/`SqlDropIndex`), like DML's `Sql*` set — but unlike DML they **execute *structurally*, not verbatim** (raw execution would lose the playground's types, named relationships, and `STRICT`; "verbatim" was a DML convenience, not a rule). Handlers **reuse the low-level schema/metadata helpers** where the operation matches simple mode and **stand alone where the SQL surface is richer** (clarity over forced refactoring); simple mode is untouched (additive). Dispatch: `create`/`drop` reuse ADR-0033 Amendment 1's category-grouped mode-aware dispatch (SQL-first, simple fallback); `alter` is a new advanced-only entry word. Full surface (no pre-emptive cuts, `Q4`): `CREATE TABLE` with column + table constraints, single/compound `PRIMARY KEY`, inline + table-level `FOREIGN KEY` → **named relationships** (one statement = one command = **one undo step**, ADR-0006); `ALTER TABLE` add/drop/rename column, `ALTER COLUMN TYPE`, add/drop constraint, add FK, **`RENAME TO`** (advanced-only table rename — new low-level op renaming the table + its CSV + the relationship and table-CHECK metadata, closing the rename half of `C1`); `CREATE [UNIQUE] INDEX` / `DROP INDEX`. Type slot accepts the ten playground keywords **and** standard-SQL aliases (`integer`→`int`, `varchar`→`text`, `timestamp`→`datetime`, …; length args accepted-and-ignored; no engine type names in/out — ADR-0030 §5). `CHECK`/`DEFAULT` reuse ADR-0031 `sql_expr`. **Pre-implementation `/runda` refinements (2026-05-24, user-confirmed):** `CREATE TABLE`/`DROP TABLE` **admit `IF [NOT] EXISTS`** (no-op-that-succeeds-with-a-note — a near-universal cross-vendor idiom, reclassified *into* scope, not engine-specific); `INTEGER PRIMARY KEY` maps to a **plain `int`** PK, *not* auto-increment (`serial` stays the sole auto-increment type). **Column-type-conversion is unified** (ADR-0017 engine, mode-appropriate policy): clean auto-converts and incompatible/own-type-static cases refuse in both modes, but a **lossy** change refuses-by-default in simple mode (`--force-conversion` opts in) while advanced mode **performs it with a loss note** and relies on **`undo` as the safety net** — no force flag, no dropping to simple mode (a payoff of shipping ADR-0006 first). OOS: views/triggers/txn-control/PRAGMA/etc. (ADR-0030 §3), the Postgres `USING` clause, and the DSL→SQL teaching echo (ADR-0030 Phase 5). Sub-phases 4a–4i, plus **4a.2** (per-column `CHECK`/`DEFAULT` via raw `sql_expr` text — `sql_expr` is validate-only, no `Expr` AST — + composite `UNIQUE(a,b)`; no new internal table) and **4a.3** (table-level/multi-column `CHECK`, landed via the new `__rdbms_playground_table_checks` metadata table because SQLite has no PRAGMA for CHECK; the builder tells a table-level CHECK from a column-level one by element position) and **4b** (foreign keys — inline `REFERENCES` + table-level `FOREIGN KEY` → ADR-0013 named relationships in the create transaction, one undo step; self-references + bare `REFERENCES <parent>` supported, user-confirmed) and **4c** (`DROP TABLE [IF EXISTS]` → `SqlDropTable`, reusing `do_drop_table`; `IF EXISTS` is a no-op-with-note via `DropOutcome::Skipped`) and **4d** (`CREATE [UNIQUE] INDEX [IF NOT EXISTS] [<name>] ON <T> (cols)` → `SqlCreateIndex` and `DROP INDEX [IF EXISTS] <name>` → `SqlDropIndex`, reusing `do_add_index`/`do_drop_index`; **`CREATE UNIQUE INDEX` admitted** — ADR-0025 **Amendment 1** — via an additive `IndexSchema.unique` flag that round-trips through `project.yaml` and rebuild, with `[unique]` markers in the structure view + items panel, while simple-mode `add unique index` stays deferred; `IF [NOT] EXISTS` reuses the 4c skip path; `create`/`drop` each gain a *second* advanced node, exercising the all-candidates dispatch) and **4e** (`ALTER TABLE` add/drop/rename column → `SqlAlterTable`; `alter` is a new advanced-**only** entry word, runtime-decomposed to the existing `do_add_column`/`do_drop_column`/`do_rename_column` — no new worker layer; `do_add_column` extended to consume raw `default_sql`/`check_sql` so ADD COLUMN reaches CREATE-TABLE constraint parity; drop/rename refuse a column any CHECK references (table-level AND column-level, incl. a column's own self-check on rename) — the 4a.3 deferral, via a raw-CHECK-text tokenizer in the shared executors, so it guards both surfaces and fixes a latent rename-drift bug; SQL DROP COLUMN refuses an index-covered column with no `--cascade` spelling; the column executors + `do_add_index` gained an internal-`__rdbms_*`-table guard — all user-confirmed) and **4f** (`ALTER TABLE … ALTER COLUMN TYPE` → a fourth `AlterTableAction`, runtime-decomposed to the existing `change_column_type` with `ChangeColumnMode::ForceConversion` — which **is** the §7 advanced policy: lossy converts *with a note* (no force flag), incompatible + ADR-0017 static refusals (`↔ blob`, same-type, `date ↔ datetime`, non-`int → serial`) still refuse, while **`int → serial` is allowed** (auto-fills nulls + UNIQUE, ADR-0018 §8 — the §7 "→serial refused" summary is looser than the code); the builder discriminates the fourth branch by the **`type` keyword** (unique — ADD COLUMN's type is an ident), the type slot reuses `SQL_TYPE`; the internal-`__rdbms_*` guard was folded into `do_change_column_type`, closing the simple `change column` exposure too — user-confirmed) and **4g** (`ALTER TABLE … ADD [CONSTRAINT <name>] (CHECK | UNIQUE | FOREIGN KEY)` + `DROP CONSTRAINT <name>`; ADD = CHECK + composite UNIQUE + FK, with `ADD PRIMARY KEY` and a *named* UNIQUE refused — composite UNIQUE is anonymous in our model; each ADD reuses a low-level path (table-CHECK/UNIQUE rebuild with a dry-run guard; FK → `add_relationship`, bare `REFERENCES <P>` → parent single-PK), DROP CONSTRAINT resolves the name to a table-CHECK then a child-side FK; **named table-CHECKs round-trip** via a nullable `name` column on `__rdbms_playground_table_checks` (**rebuild-only** arrival — pre-4g projects gain it on `rebuild`, a named add on an un-upgraded project is refused with a friendly "rebuild first" message) *and* a `project.yaml` `check_constraints` extension to an `{expr, name}` mapping (the bare-string form still reads); the internal-`__rdbms_*` guard was folded into `do_add_constraint`/`do_add_relationship`, completing that guard class — all user-confirmed) and **4h** (`ALTER TABLE … RENAME TO` — the one genuinely new low-level op, `do_rename_table`: a native engine rename plus one-transaction reconciliation of every metadata row naming the table (`__rdbms_playground_columns`, **both ends** of `__rdbms_playground_relationships`, `__rdbms_playground_table_checks`), the CSV file (the existing rewrite+delete path — no new persistence method), and **CHECK text that qualifies a column with the old table name** (`T.age`→`U.age`, a planning-`/runda` finding — the engine rewrites the live CHECK but the stored text would drift and break a fresh rebuild; `rewrite_check_table_qualifier` keeps them in step); grammar splits the `rename` verb into one branch with an inner Choice on a distinct second keyword (`column` vs `to`), the new-name slot mirroring the `CREATE TABLE` name slot; refuses same-name / existing-target / `__rdbms_*` / non-existent, with **case-insensitive** collision checks behind an engine-neutral pre-check (a finished-slice `/runda` finding — the engine matches names case-insensitively); auto-named indexes *and* relationships keep their stale names (only table-name columns update — §6 scope); one undo step; advanced-only, closing the rename half of `C1` — all user-confirmed) and **4i** (the verification sweep that completes Phase 4: the shared-entry-word completion merge + the simple-vs-advanced completion colour-when-mixed with Both→Advanced→Simple block ordering; `describe` of table-level composite UNIQUE + table CHECK; the self-ref FK pre-submit indicator fix; and the CREATE-TABLE help/usage skeleton refresh). **All of Phase 4 (4a–4i) is shipped.** Each sub-phase has exit + DA gates; **Amendment 2, 2026-05-27** (design agreed, pending impl): a **standard-first dialect stance** (refines ADR-0030's "standard SQL" posture — ISO spelling is canonical + echoed where one exists; a vendor shorthand may be *accepted* but isn't canonical; where ISO offers none, *one* documented vendor spelling is a deliberate extension) + an `ALTER COLUMN` **constraint gap-fill** surfaced by the ADR-0038 echo design: makes ISO `ALTER COLUMN … SET DATA TYPE` the canonical type-change verb with `TYPE` retained as a synonym (**reverses §4f's "no `SET DATA TYPE`"**), and adds `SET/DROP DEFAULT` (ISO) + `SET/DROP NOT NULL` (the one documented extension — ISO has no in-place NOT-NULL verb; PostgreSQL's chosen for being type-independent), all **rebuild-backed via the existing ADR-0029 `do_add_constraint`/`do_drop_constraint` executors** (dry-run + internal-table guards free, no new worker layer), reaching simple↔advanced constraint-mod **parity for NOT NULL + DEFAULT**; the **rebuild stays hidden** (Category-1 engine detail, ADR-0038). Residual gap left open + flagged: dropping a **column-level (anonymous) UNIQUE/CHECK** (no portable name — same class as Am1's parallel gap), which ADR-0038's catalogue marks "no headline echo"
- [ADR-0036 — Value validation for advanced-mode DML](0036-typed-dml-values-vs-verbatim.md) — **Accepted** (design agreed + `/runda`'d 2026-05-26; mechanism then **deliberately narrowed** from "bind literals via the DSL path" to surgical **"validate-and-retain, execute verbatim"** after the user resisted consolidating the modes and a concrete auto-fill difference confirmed even the single-row literal case isn't identical across modes; **Phases 1–2 implemented** 2026-05-26 — `INSERT … VALUES` and `UPDATE … SET` literal validation + offending-value retention, capture-at-parse with no grammar change; **Phase 3a implemented** 2026-05-26 — live typed-slot hints + numeric-shape highlighting for `UPDATE`/UPSERT `SET col = <literal>` via a boundary-aware lookahead (Amendment 1 corrects this ADR's naive-`Choice` sketch); **Phase 3b implemented** 2026-05-27 — per-position typed slots for `INSERT … VALUES` (single/multi-row, Form A/B) via a new zero-width `Node::SetColumn` primitive + an arity-gating tuple lookahead that preserves the §8.1 arity diagnostic; **fully implemented**). **Augments — does NOT supersede — ADR-0030 §4 / ADR-0033 §10**: execution stays verbatim, ADR-0033 Amendment 3's two-command identity (`Insert` vs `SqlInsert`) **stands**. The problem (investigated 2026-05-26; characterization test `sql_insert.rs::sql_dml_skips_app_level_value_validation_that_the_dsl_enforces` proves it): advanced-mode SQL DML gets **none** of the DSL's value feedback — a malformed `date` like `2025/01/15` is silently written, and the offending value is missing from constraint errors — because literal values are spliced into text and discarded (only `STRICT` storage types check them). **Fix (surgical): validate each literal value against its column type before the verbatim insert, and retain it for error reporting — sharing only the per-type validators (`Value::bind_for_column`/`validate_date`/`shortid::validate`), nothing else.** No binding, no statement reconstruction, no auto-fill change, no command-identity collapse — because the two gaps are closed by validation + retention alone, and executing the user's own text is already safe. The literal set = `NULL`/boolean/string/**signed**-numeric; arithmetic/functions/subqueries/column-refs are expressions (skipped — the engine evaluates them). `WHERE` not validated (it's an expression in general; motivation met by `VALUES`/`SET`); `SELECT`/`INSERT … SELECT`/`RETURNING`/`ON CONFLICT` need no special handling since execution is untouched. Phased: **Phase 1** capture-at-parse + validate + retain for `INSERT … VALUES` (no grammar change, no reparse — closes both proven gaps); **Phase 2** `UPDATE … SET` literals; **Phase 3** completion hinting/highlighting (the only part needing a grammar change — a typed-literal slot vs `sql_expr` reusing the DSL `TypedValueSlot`s at `data.rs:141`/`189`/`269`, discriminated by a **boundary-aware lookahead** not a naive `Choice` per **Amendment 1**; split into **3a** `SET` (done) and **3b** `VALUES` (pending); supersedes only Phase 1/2's literal *detection*, not the validation/enrichment on top). Non-goals: binding/reconstruction, collapsing command identity (Am3 stands), changing `serial`/`shortid` auto-fill (`requirements.md` **X4**, a separate possible-bug), a structural `SELECT`, a full SQL-expression AST. Embodies `requirements.md` **X5** (share a *mechanic*, not a *command*); the neutral "that value" safety net (ADR-0035 Amendment 1) stays correct for genuinely-computed values; **Amendment 2 (issue #17, 2026-05-29)** brings the §8.1 arity diagnostic to **simple mode** at parity with advanced: a `tuple_value_list`-style gate (`dsl_insert_value_list`, **simple-mode-gated** so advanced is byte-for-byte unchanged) routes a wrong-count DSL insert tuple to the type-blind fallback so it matches and the friendly arity diagnostic fires (instead of a bare `expected `,`/`)``); `dml_insert_arity_diagnostics` is now mode-aware (advanced Form B = all columns, simple Form B/C = user-fillable since serial/shortid auto-fill, ADR-0018 §3), counts the DSL Form A role (`insert_first_item`) and the keyword-less Form C tuple, with new keys `insert_arity_mismatch_form_b_simple` / `_all_auto`; a wrong-count DSL insert now parses `Ok` + carries the ERROR diagnostic (the `[ERR]` verdict), with a unified Ok-arm submit pre-flight (`dsl_insert_count_mismatch_notes`) blocking dispatch + teaching (the issue #1 Err-arm note retires). **Arity-UX parity only — no consolidation of value-handling/execution/auto-fill; the deliberate mode-distinctness stands**
- [ADR-0037 — Execution-time mode side-channel (the three-way submission mode)](0037-execution-time-mode-side-channel.md) — **Accepted** (design agreed 2026-05-27; channel **implemented + verified end-to-end** by its motivating consumer — ADR-0038's fully-shipped DSL → SQL teaching echo — across handoff-46 `04c8e42` (channel + first echo slice), handoff-47 `90479cb` (full Bucket A), `275c726` (Bucket B resolved-name + multi-statement renderers), `e6ad1ae` (the category-3 `--dont-convert` caveat — gated on this channel too), and `2aab457` (the §4 styled-runs rendering polish)), **redeems the follow-up deferred by ADR-0033 Amendment 3** (which named this ADR and its motivating consumer). Establishes the channel that lets a command know, **at execution time**, the effective mode it ran under — so execution can adjust **output** without touching **identity** (the motivating case: a DSL-form `create table` echoing the equivalent SQL when run in advanced mode, silent in simple — ADR-0030 §10, realised by ADR-0038). Introduces a **new per-submission enum `SubmissionMode` { Simple, Advanced, AdvancedOneShot }** — *refining* Amendment 3's "widen `Mode`" sketch: the persistent input `Mode` stays **two-way** (`mode.rs` keeps the one-shot `:` out of persistent state), and the three-way distinction lives on the per-submission channel where the transient `:` belongs. Resolved at submit time (Simple+`:` → `AdvancedOneShot`; Advanced `:` is a no-op), threaded through `Action::ExecuteDsl` → worker, **output-only** (no executor branches its *effect* on it — Amendment 3 forbids behavioural mode dependence). The worker builds the teaching echo (+ category-3 expansion data — ADR-0038) for DSL-form commands in advanced/one-shot mode and returns it; the App renders it beneath `[ok]`. Co-located with execution because the echo's harder forms (resolved auto-names, generated `shortid`s, conversion counts) are worker-computed facts, and gating on mode means the work happens only when shown. Alternatives weighed + rejected: widening `Mode` (conflates transient/persistent state); App-side gating with the worker always emitting echo data (computes unconditionally, doesn't generalise, re-opens the render-side framing ruled against). Scope: channel + resolution rule only — the renderer/catalogue/`Value → SQL-literal` are ADR-0038, the `ALTER COLUMN` gap-fill is the ADR-0035 amendment
- [ADR-0038 — The DSL → SQL teaching echo](0038-dsl-to-sql-teaching-echo.md) — **Accepted** (design agreed 2026-05-27; **fully implemented + verified** — every catalogue row in §7 Buckets A + B and the §6 category-3 prose round-trips per line through the advanced walker per §1, and the §4 de-emphasised styled-runs polish is wired: handoff-46 `04c8e42` shipped the channel + create-table slice, handoff-47 `90479cb` the full Bucket A expansion + a skeleton contract-gap fix (dropped per-column `DEFAULT`/`CHECK`), `275c726` the Bucket B resolved-name + multi-statement renderers (auto- and user-named `add index`, positional `drop index`, `add`/`drop relationship` in both selector forms, `drop column --cascade`, `add relationship --create-fk`), `e6ad1ae` the last category-3 line — the `change column --dont-convert` *caveat* (shortid + transform notes were already surfaced via pre-existing `client_side.*` keys), and `2aab457` the §4 styled-runs polish: a new `OutputKind::TeachingEcho` custom rendering branch (dimmed `Executing SQL:` prefix + the SQL re-lexed in advanced mode for token-class colouring, same as the input echo) plus a new `OutputStyleClass::Hint` for every cat-3 prose line — caveat *and* the existing illuminating notes, user-confirmed broader scope), **realises ADR-0030 §10** (the teaching bridge) — the Phase-5 echo **ADR-0035 §12 forward-referenced** — building on **ADR-0037** (the `SubmissionMode` gate) and **ADR-0035 Amendment 2** (standard-first dialect + `ALTER COLUMN` gap-fill). When a **DSL-form** command runs in advanced/one-shot mode, the worker emits the equivalent SQL beneath `[ok]` as a de-emphasised styled `OutputLine` (ADR-0028); the App renders it. **Defining invariant — the copy-paste contract:** every echoed line is *runnable advanced-mode SQL* (round-trip-tested: parse the echo → same-effect command; a planned "copy the echo" affordance depends on it). **Type vocabulary = the playground's own keywords** (`serial`/`shortid`/…, accepted by `from_sql_name`, decision (a)); **statement shape = the standard-first dialect** (Am2). **DML uses substituted literals, not `?`** (per-type `Value → SQL-literal`, round-trip-safe; `blob` moot — no literal syntax exists; auto-gen columns omitted to match `do_insert` + X4). **Firing reality — a DDL + `show data` feature:** in advanced mode `insert`/`update`/`delete … where` are SQL-first (`Sql*` = already SQL = nothing to echo per §10); only DSL-*only* spellings echo (DDL + `show data` + the `delete`/`update … --all-rows` fall-throughs — the latter via **ADR-0033 Amendment 4**, a bug-fix folded in here that reverses Amendment 3's `update … --all-rows` misparse). **Three-category framework** for "what happens beyond the literal SQL": **(1) engine-implementation-hiding** (the rebuild, rowid PK, non-PK `serial` MAX+1) — *never surfaced*; **(2) decomposable into advanced SQL** (`drop column --cascade`, `--create-fk` relationship) — *shown as the runnable multi-line sequence, one statement per line*; **(3) playground type-behaviour with no SQL-expressible form** (`shortid` generation — no `shortid()`; type-conversion transforms — no `USING`) — *de-emphasised prose expansion from the worker's `client_side.*` notes*. Carries the **full catalogue** (Buckets A single-statement / B resolved-name + multi-line / C no-echo) mapping every DSL-form command to its echo. OOS: reverse SQL→DSL echo (§13 OOS-5), app commands / `show table` / `explain` / `replay`, a `blob` literal, the column-level UNIQUE/CHECK drop residual (Bucket C until Am2's gap closes), and surfacing any category-1 engine internal
- [ADR-0039 — EXPLAIN over advanced-mode SQL queries](0039-explain-over-advanced-sql.md) — **Accepted** (2026-05-27), **implemented 2026-05-30 (issue #7)**, **supersedes ADR-0030 §13 OOS-2**. Lets `explain` wrap the advanced SQL commands (`Select`/`SqlInsert`/`SqlUpdate`/`SqlDelete`, plus `with`/CTE which builds a `Select`) in addition to the DSL `ShowData`/`Update`/`Delete` it already covers (ADR-0028), running `EXPLAIN QUERY PLAN` over the validated SQL text through the existing ADR-0028 span-styled plan tree (advanced mode only; DSL `explain` unchanged in both modes). Implemented via a second `Advanced` `explain` CommandNode (`EXPLAIN_SQL`) registered under the shared `explain` entry word — reusing the established `insert`/`update`/`delete` shared-word dispatch (`decide`: SQL-first / DSL-fallback), so `explain show data …` and DSL-only `--all-rows` still reach the DSL node; rejected a `DynamicSubgrammar` mode-gate (its resolution cache key omits `mode`). `build_explain_sql` slices the inner SQL off the source (excludes `explain`) and reuses the existing SQL builders; `do_explain_plan` runs the carried text verbatim, no params. Advanced `explain update`/`delete` now route through SQL (identical plan, full SQL syntax); DSL-explain tests pinned to simple mode. Reframed OOS-2 as a *deferred* exclusion (per ADR-0000's out-of-scope discipline), not a rejection. OOS (deferred): EXPLAIN of DDL (no query plan exists)
