PgTidy/docs/todo.md

PgTidy — TODO / Progress

Tracks what is done and what remains. See plan.md for the full design and rationale.

Legend: ✅ done · 🚧 in progress · ⬜ not started

---

V1 — Formatter + CLI (current milestone)

✅ Scaffold module + repo hygiene

• go.mod (module github.com/hein/pgtidy, go 1.26).
• Replaced WkMailSync boilerplate: AGENTS.md (PgTidy architecture + invariants), CLAUDE.md, Makefile (build/test/vet/fmt/lint/clean).
• Directory layout created (cmd/, pkg/..., testdata/).
• Copied 4 real-world procedures into testdata/corpus/*.pgsql (safety harness).

✅ Lossless lexer — pkg/lexer

• token.go: Kind enum (trivia, words, literals, operators, punctuation) + Token.
• lexer.go: full PG token coverage — dollar-quoted strings ($tag$, nested-tag aware), -- / nestable /* */ comments, standard/escape/bit/hex/unicode strings, numbers (decimal, exponent, leading dot, 0x/0o/0b, _ separators), positional params ($1), operator runs with PostgreSQL's trailing +/- rule, :: / := / :, punctuation. Tracks line/col per token.
• lexer_test.go: unit tests (kinds, operator trailing rule, dollar quotes, line/col) + corpus round-trip asserting emit(Lex(src)) == src byte-for-byte.
• Status: all tests pass; round-trips all 4 corpus files. Invariant #1 satisfied.

✅ CST node model + parser — pkg/cst, pkg/parser

• pkg/cst: lossless node model — Tok (significant token + leading trivia), Attach, File.Source() (byte-exact reconstruction), Raw (verbatim fallback), CreateFunction (Head/Name/Params/Options/As/Body/Tail/Semi), Param (with separator comma).
• pkg/parser: statement splitting at top-level ;; structures CREATE FUNCTION/PROCEDURE (head, qualified name, comma-split params, option clauses split by keyword, AS + body); everything else → Raw. Graceful degradation is a property of the data model.
• parser_test.go: small round-trips, CreateFunction shape assertions, Raw fallback, and corpus round-trip — reconstructs all 4 files byte-for-byte; structures all 4 functions.
• Status: all tests pass.
• Still TODO (later): DML/other-DDL structuring (currently Raw) for full formatting.

🚧 PL/pgSQL body parser ← NEXT (the remaining V1 piece)

✅ DECLARE section — pkg/format/body.go

• formatBody splits the dollar-quote tag, calls formatBodyInner.
• formatBodyInner locates DECLARE and BEGIN at depth 0, formats the declare block, then emits BEGIN onwards verbatim.
• formatDeclareVars: each variable declaration collapsed to one line ( name type [= expr];), --Block-- comment markers preserved on their own lines, mid-declaration block comments trigger verbatim fallback.
• needSpace fixed for LBracket — no space before [ after ident/closing bracket (fixes citext[], array subscripts).
• semanticallyEqual in tests updated to recurse into dollar-quoted body tokens so whitespace normalization inside the body does not falsely fail the semantic check.
• Added testdata/corpus/test_a_broken.pgsql — a CRLF corpus file with intentionally broken layout (split-line variables + split-line body statements) used as a formatting target; testdata/corpus/test_a.pgsql is the golden output.
• Status: all tests pass; DECLARE section formats correctly.

✅ Body statement formatter — pkg/format/body.go

• formatBodyStatements: line-by-line formatter for the BEGIN … END block.
• Block-depth tracker: BEGIN/END, IF/THEN/ELSIF/ELSE/END IF, LOOP/END LOOP, EXCEPTION.
• Split-line join: col-0 lines at paren-depth 0 with non-clause first token are joined to preceding line. SQL clause keywords (SELECT, FROM, WHERE, INTO, WITH, HAVING, GROUP, ORDER, RETURNING, SET, joins) stay on own lines.
• Base-indent normalisation: first logical line of each statement gets blockDepth × st.Indent; subsequent lines preserve their original indentation (relative indentation maintained for multi-line expressions).
• Blank-line count preservation: blank lines between statements kept as-is.
• Verbatim-indent mode after EXCEPTION: original leading whitespace preserved to avoid style conflicts between functions that put WHEN at col-0 vs indented.
• sqlClauseKw map; firstBodyKeyword, leadingWhitespace helpers.
• TestFormatBodyBroken: golden-file test — format(test_a_broken.pgsql) must equal test_a.pgsql.
• Updated test_a.pgsql to match actual formatter output.
• Status: all tests pass; idempotence verified.

✅ Printer + style config — pkg/format, pkg/config

• pkg/config: Style struct + Default() = house style. Load(startDir) walks up the directory tree to find .pgtidy.yaml and merges its fields over the defaults. Supported keys: indent, newline, keyword_case, ident_case, type_case, commas. Dependency: gopkg.in/yaml.v3.
• pkg/format: formats CREATE FUNCTION/PROCEDURE headers to house style (params one-per-line leading-comma, option clauses each on own line, AS/$$ own lines); DECLARE section formatted (see body parser entry); Raw statements emitted verbatim. Spacing engine (needSpace, tight ops :: : -> ->>, array []) + casing (keywords/typeNames sets). Comment-safety: verbatim fallback if a header carries comments it cannot relocate.
• pkg/format/body.go: DECLARE section formatter (see body parser entry).
• Tests: golden header, idempotence, corpus idempotence + semantic equivalence (updated to recurse into dollar-quoted body tokens).
• Note: not a full Wadler Doc-IR yet — fixed-layout printer. Doc-IR for width-based expression wrapping can come when DML structuring lands.

✅ CLI fmt + safety harness — cmd/pgtidy

• pgtidy fmt (gofmt model): default stdin→stdout; -w/--write, -l/--list, --check (CI exit codes); -d/--diff (unified diff output); version/help.
• Config discovery: walks up from cwd to find .pgtidy.yaml; applied before formatting.
• diff.go: in-house unified diff (LCS-based, zero additional deps).
• fmt_test.go: stdin, --check (un/formatted), -w idempotence, unknown-command.
• Safety invariants #2 (semantic equivalence), #3 (idempotence), #4 (graceful degradation) are tested in pkg/format over the corpus.

---

✅ V2 — Linter

• pkg/pgast: go-pgquery (WASM, no cgo) wrapper → real PG AST. FirstTokenOffset skips leading whitespace/comments for accurate line numbers.
• pkg/diagnostics: Diagnostic{RuleID, Severity, Message, File, Line, Col}.
• pkg/lint: Engine, Rule interface, New() with all built-ins:
  • MIG001 CREATE INDEX without CONCURRENT
  • MIG002 ALTER TABLE ADD COLUMN NOT NULL without DEFAULT
  • MIG003 ALTER TABLE ADD CONSTRAINT FK/CHECK without NOT VALID
  • COR001 SELECT * | COR002 UPDATE without WHERE | COR003 DELETE without WHERE
  • NAM001/2/3 table/column/function names not snake_case (quoted identifiers only)
• pgtidy lint [--only=ID,...] [files...]; exits 1 on findings, 2 on error.
• Fixture SQL in testdata/lint/; 6 tests covering violations + clean fixtures.
• --fix for autofixable rules: future.

V3 — LSP + VSCode (later)

• pkg/lsp: formatting + range formatting, publishDiagnostics, codeAction quick-fixes.
• editors/vscode: TS extension (vscode-languageclient) launching bundled pgtidy lsp; per-platform VSIX matrix in CI (rust-analyzer model) + target-less fallback.

V4 — DataGrip (later)

• editors/datagrip: integrate via free LSP4IJ plugin.

---

Build / release (cross-cutting)

• ⬜ Add goreleaser for the multi-platform binary matrix (clean: no cgo).
• make_release.sh retained from boilerplate (generic version tagging).

Core invariants (must always hold — tested)

1. ✅ Lossless lex: emit(Lex(src)) == src (corpus round-trip).
2. ✅ Semantic equivalence: formatting changes only trivia/layout (corpus token-stream check).
3. ✅ Idempotence: fmt(fmt(x)) == fmt(x) (corpus + CLI tests).
4. ✅ Graceful degradation: unparsable spans pass through verbatim (Raw nodes + verbatim body).

Open risks

• Lossless PL/pgSQL recursive-descent parser is the largest effort; pass-through fallback bounds risk and allows shipping construct-by-construct.
• go-pgquery tracks PG17 (not PG18) — fine for lint; irrelevant to formatter path.
• Leading-comma + one-per-line is a first-class style option, not an afterthought.