fix: deserialize should only expose @Exposed fields

Author: ryanrasti

AGENTS.md

@@ -0,0 +1,19 @@
+# Agent notes
+
+Conventions that aren't lint-enforced. If you're writing code in this repo, follow these.
+
+## Type identifiers
+
+- **Don't use TS's `Record<K, V>` utility type.** Use `{ [k: K]: V }` directly.
+
+  Reason: typegres exports its own `Record` class (the pg composite/row type), and `Record<K, V>` as a type position resolves to TS's global utility — they're not the same shape, and the visual collision causes confusion. ESLint can't distinguish the two reliably (it's identifier-name-based, not type-aware), so this is a convention rather than a lint rule.
+
+  ```ts
+  // Don't:
+  const headers: Record<string, string> = {};
+
+  // Do:
+  const headers: { [k: string]: string } = {};
+  ```
+
+  Using the typegres `Record` class as a type (e.g. `Record<O, 1>` as a return of `scalar()`) is fine — that's the intended use of the exported class.

eslint.config.js

@@ -54,13 +54,6 @@ export default [
         selector: "MemberExpression[object.name='expose'][property.name='unchecked']",
         message: "Don't use @expose.unchecked — it skips RPC arg validation. Use @expose(zSchema) instead. If the method's signature is genuinely inexpressible in zod (or this is a test fixture), add `// eslint-disable-next-line no-restricted-syntax -- <reason>`.",
       }],
-      "@typescript-eslint/no-restricted-types": ["error", {
-        types: {
-          "Record": {
-            message: "Use { [key: string]: T } instead. 'Record' conflicts with the pg Record type.",
-          },
-        },
-      }],
     },
   },
   {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "typegres",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "type": "module",
   "main": "./dist/index.mjs",
   "types": "./dist/index.d.mts",

src/builder/query.test.ts

@@ -2,6 +2,7 @@ import { test, expect, expectTypeOf } from "vitest";
 import { Int4, Int8, Text, Bool, Jsonb } from "../types";
 import { sql, compile } from "./sql";
 import { setupDb, db } from "../test-helpers";
+import { expose } from "typegres";
 setupDb();
 
 // --- values() ---
@@ -742,6 +743,9 @@ test("groupBy: multiple calls stack", async () => {
     )
     .groupBy((n) => [n.values.a])
     .groupBy((n) => [n.values.b])
+    // @ts-expect-error --- TODO: typing here is broken as the tuple
+    //  type intersected with the namespace (with the previous tuple) isn't
+    //  quite correct
     .select(({ 0: a, 1: b, values }) => ({ a, b, total: values.c.sum() }))
     .orderBy((n) => [n[0] as any, "asc"])
     );
@@ -852,7 +856,9 @@ test("type test: db.execute(Table.from()) row methods are never-typed (uncallabl
     await tx.execute(sql`INSERT INTO widgets (name) VALUES ('w1')`);
 
     class Widgets extends db.Table("widgets") {
+      @expose()
       id   = (Int8<1>).column({ nonNull: true, generated: true });
+      @expose()
       name = (Text<1>).column({ nonNull: true });
 
       // Plain method — should not be a callable function on the row type.

src/builder/query.ts

@@ -9,16 +9,13 @@ import { isTableClass, TableBase } from "../table";
 import z from "zod";
 import { Values } from "./values";
 
-// Extract only Any<> instances from a row type
-export const selectList = <T extends RowType>(output: T): T => {
-  return Object.fromEntries(Object.entries(output).filter(([, v]) => v instanceof Any)) as T;
-};
-
 // Compile a row type into a SQL select list: col AS "name", ...
-export const compileSelectList = (output: RowType): Sql => {
+export const compileSelectList = (output: RowType, omitAliases = false): Sql => {
   return sql.join(
     Object.entries(output).flatMap(([k, v]) =>
-      v instanceof Any ? [sql`${v.toSql()} as ${sql.ident(k)}`] : [],
+      v instanceof Any ? [
+        omitAliases ? v.toSql() :
+        sql`${v.toSql()} as ${sql.ident(k)}`] : [],
     ),
   );
 };
@@ -44,30 +41,6 @@ export const reAlias = <R extends RowType>(row: R, alias: Alias): R => {
   return out;
 };
 
-// Deserialize raw string rows using typed output descriptors
-export const deserializeRows = <R>(
-  rows: { [key: string]: string }[],
-  output: { [key: string]: unknown },
-): R[] => {
-  return rows.map((row) =>
-    Object.fromEntries(
-      Object.entries(row).map(([k, v]) => {
-        const type = output[k];
-        if (!(type instanceof Any)) {
-          throw new Error(
-            `deserializeRows: output column '${k}' is not a typed pg expression (got ${typeof v}). ` +
-              `The select callback must return an object whose values are Any instances.`,
-          );
-        }
-        if (v === null || v === undefined) {
-          return [k, null];
-        }
-        return [k, type.deserialize(String(v))];
-      }),
-    ),
-  ) as R[];
-};
-
 // Hydrate raw rows into typed instances that share the shape's prototype.
 // Each column field is an Any wrapping a CAST(param) of the deserialized
 // value — so methods on the class that reference `this.col` can compose
@@ -102,13 +75,19 @@ export const hydrateRows = <R>(
 };
 
 // Mapping of row name to type (class instance)
-export type RowType = object;
+export type RowType = TableBase | { [k: string]: Any<any> };
 export const isRowType = (obj: unknown): obj is RowType => {
   if (obj === null || typeof obj !== "object") {
     return false;
   }
+  if (obj instanceof TableBase) {
+    return true;
+  }
   const proto = Object.getPrototypeOf(obj);
-  return obj instanceof TableBase || proto === Object.prototype || proto === null;
+  if (proto !== Object.prototype && proto !== null) {
+    return false;
+  }
+  return Object.entries(obj).every(([_, v]) => v instanceof Any);
 };
 
 // All of the row types in the current namespace
@@ -285,7 +264,7 @@ export class QueryBuilder<
   // overload, R widens to `TableBase` and column access on the namespace fails.
   // By destructuring the constructor to `InstanceType<T>` directly, we capture
   // the concrete subclass type (`Owners`, `Pets`, …).
-  join<T extends { readonly tsAlias: string; new (): object }>(
+  join<T extends typeof TableBase>(
     from: T,
     on: (ns: N & { [K in T["tsAlias"]]: InstanceType<T> }) => Bool<any>,
   ): QueryBuilder<N & { [K in T["tsAlias"]]: InstanceType<T> }, O, GB>;
@@ -302,7 +281,7 @@ export class QueryBuilder<
     });
   }
 
-  leftJoin<T extends { readonly tsAlias: string; new (): object }>(
+  leftJoin<T extends typeof TableBase>(
     from: T,
     on: (ns: N & { [K in T["tsAlias"]]: RowTypeToNullable<InstanceType<T>> }) => Bool<any>,
   ): QueryBuilder<N & { [K in T["tsAlias"]]: RowTypeToNullable<InstanceType<T>> }, O, GB>;
@@ -426,25 +405,20 @@ export class QueryBuilder<
   // TODO: ROW(), array_agg(), COALESCE should be regular typed ops once we support them
   // Conditional return type avoids overload resolution quirks: TS's `this:`
   // overloads can pick the wrong branch when the Card type is already narrowed.
-  /* eslint-disable @typescript-eslint/no-restricted-types */
   scalar(): [Card] extends ["one"]
     ? Record<O, 1>
     : [Card] extends ["maybe"]
       ? Record<O, 0 | 1>
       : Anyarray<Record<O, 1>, 1>;
-  /* eslint-enable @typescript-eslint/no-restricted-types */
   @expose()
   scalar(): any {
-    const staticCols = selectList(this.rowType());
-    const RecordClass = Record.of(staticCols as any);
+    const RecordClass = Record.of(this.rowType());
 
     // Wrap as a subquery: (SELECT ROW(...) FROM ... WHERE ...)
     // inner QB — when embedded in sql``, its emit() wraps as subquery with AS
     const inner = this.select((ns) => {
-      const cols = selectList(this.#doSelect(ns));
-      const rowExprs = Object.values(cols).map((type: any) => type.toSql());
       // ROW() takes raw expressions without aliases
-      const rowSql = sql`ROW(${sql.join(rowExprs)})`;
+      const rowSql = sql`ROW(${compileSelectList(this.#doSelect(ns), true)})`;
       return { __row: RecordClass.from(rowSql) };
     });
     if (this.card === "many") {

src/database.ts

@@ -1,6 +1,7 @@
 import type { ExecuteFn, Driver, QueryResult } from "./driver";
 import type { Fromable, RowType, RowTypeToTsType } from "./builder/query";
-import { QueryBuilder, deserializeRows, hydrateRows } from "./builder/query";
+import { QueryBuilder, hydrateRows } from "./builder/query";
+import { deserializeRows } from "./util";
 import type { Sql } from "./builder/sql";
 import { sql } from "./builder/sql";
 import { Table, type TableBase, type TableOptions } from "./table";
@@ -78,14 +79,14 @@ export class Database<C = undefined> {
   async execute(query: Sql): Promise<any> {
     const result = await this.#exec(query);
     if (query instanceof QueryBuilder) {
-      return deserializeRows(result.rows as { [key: string]: string }[], query.rowType() as { [key: string]: unknown });
+      return deserializeRows(result.rows as { [key: string]: string }[], query.rowType());
     }
     if (query instanceof InsertBuilder || query instanceof UpdateBuilder || query instanceof DeleteBuilder) {
       const returning = query.rowType();
       if (!returning) {
         return [];
       }
-      return deserializeRows(result.rows as { [key: string]: string }[], returning as { [key: string]: unknown });
+      return deserializeRows(result.rows as { [key: string]: string }[], returning);
     }
     return result;
   }

src/exoeval/tool.ts

@@ -4,6 +4,13 @@ import z from 'zod'
 export const toolSymbol = Symbol.for('exoeval_tool')
 export const toolFieldsSymbol = Symbol.for('exoeval_toolFields')
 
+// Reads the `@expose` marker if present. Returns the Set when the
+// output is a marker-bearing instance (a typegres Table row); returns
+// `undefined` for POJOs (no filter applies). Callers extract once and
+// pass the result to consumers like `deserializeRows` / `Record.of`.
+export const exposedFieldsOf = (output: object): Set<string> | undefined =>
+	(output as { [k: symbol]: unknown })[toolFieldsSymbol] as Set<string> | undefined
+
 export type ToolKind = 'raw' | 'expr' | 'constructor'
 
 export type ToolFunction<T extends (...args: unknown[]) => unknown = (...args: unknown[]) => unknown> = T & ((...args: unknown[]) => unknown) & {

src/hydrate.test.ts

@@ -1,5 +1,5 @@
 import { describe, test, expect, expectTypeOf, beforeAll } from "vitest";
-import { typegres, sql, Table, Int8, Text, Bool } from "typegres";
+import { typegres, sql, Table, Int8, Text, Bool, expose } from "typegres";
 import type { Database, QueryBuilder } from "typegres";
 
 // End-to-end tests for db.hydrate(): materialize query rows as class
@@ -17,9 +17,16 @@ class User extends Table("users") {
 }
 
 class Todo extends Table("todos") {
+  @expose()
   id = (Int8<1>).column({ nonNull: true, generated: true });
+
+  @expose()
   user_id = (Int8<1>).column({ nonNull: true });
+
+  @expose()
   title = (Text<1>).column({ nonNull: true });
+
+  @expose()
   completed = (Bool<1>).column({ nonNull: true });
 
   update(fields: { completed?: boolean; title?: string }) {