fix(postgrest-typegen): infer nullability on PostgreSQL 14

packages/postgrest-typegen/CLAUDE.md

@@ -37,7 +37,8 @@ Hard split between **introspection** and **generation**:
   (`pg_proc.prosqlbody`) and reads the function comment's `@notNull` lines (see
   "View column nullability" and "`RETURNS TABLE` column nullability" in the
   README). It reads only the join tree and range table, never `varnullingrels`,
-  so one code path serves PostgreSQL 15 and later.
+  so one code path serves PostgreSQL 14 and later. PostgreSQL 14 names range
+  table entries `RTE` where later versions write `RANGETBLENTRY`.
 - `src/generation/` -- `generateTypescript` / `generateGo` / `generatePython`.
   Pure functions: `GeneratorMetadata` in, the complete source file (ending in a
   single newline) out. No database access.
@@ -150,3 +151,10 @@ extend `sortGeneratorMetadata` instead.
 - Generation unit tests: pure, no Docker, fixture-builder + per-language inline
   snapshots (`src/` and `test/generation/`).
 - Introspection/parity tests: `bun:test` + testcontainers PostgreSQL.
+- PostgreSQL 14 is the minimum supported version. The parity test runs on it and
+  on PostgreSQL 15 against the same goldens, so every introspection query has to
+  run on 14 and produce the same metadata there. The version-specific suites
+  (view and `RETURNS TABLE` nullability) include 14 as well. Raising the minimum
+  changes `MINIMUM_POSTGRES_VERSION` in `test/parity/parity.test.ts`, the
+  version lists of those suites and "Supported PostgreSQL versions" in the
+  README together.

packages/postgrest-typegen/README.md

@@ -287,6 +287,12 @@ npm install pg
 npm install oxfmt@0.66.0
 ```
 
+## Supported PostgreSQL versions
+
+`introspect()` supports PostgreSQL 14 and later, the same versions the Supabase
+CLI accepts as `db.major_version`. View and `RETURNS TABLE` column nullability
+are inferred the same way on every supported version.
+
 ## postgrest-js type tests
 
 Every pull request that touches this package also runs postgrest-js's type tests

packages/postgrest-typegen/src/introspection/view-nullability.ts

@@ -66,7 +66,7 @@ export interface QueryNullability {
  * joins, subqueries, non-recursive CTEs and `GROUP BY`, and nothing on the way
  * puts it on the nullable side of an outer join, in a set operation or under
  * grouping sets. The outer-join check walks the join tree instead of reading
- * `varnullingrels`, which PostgreSQL 15 does not have.
+ * `varnullingrels`, which PostgreSQL 14 and 15 do not have.
  */
 export function queryNullability(
   rows: ViewDefinitionRow[],
@@ -152,7 +152,7 @@ export function queryNullability(
       return false;
     }
     const entry = list(query.fields.rtable)[varno - 1];
-    if (!isNode(entry, "RANGETBLENTRY")) {
+    if (!(isNode(entry, "RANGETBLENTRY") || isNode(entry, "RTE"))) {
       return false;
     }
     switch (entry.fields.rtekind) {

packages/postgrest-typegen/test/introspection/function-result-nullability.test.ts

@@ -87,7 +87,7 @@ const resultNullability = (metadata: GeneratorMetadata, name: string) =>
     ).map((column) => [column.name, column.is_nullable]),
   );
 
-describe.each(["15", "17", "18"])(
+describe.each(["14", "15", "17", "18"])(
   "RETURNS TABLE column nullability (PostgreSQL %s)",
   (version) => {
     let container: StartedPostgreSqlContainer;

packages/postgrest-typegen/test/introspection/view-nullability.test.ts

@@ -11,10 +11,11 @@ import { introspect } from "../../src/introspection/index.ts";
 import type { GeneratorMetadata } from "../../src/types.ts";
 
 /**
- * Integration coverage for view column nullability. PostgreSQL 15 has no
- * `varnullingrels`, PostgreSQL 18 routes grouped columns through a group range
- * table entry, and PostgreSQL 17 is what Supabase projects run, so each of them
- * must resolve the same columns as non-null.
+ * Integration coverage for view column nullability. PostgreSQL 14 names range
+ * table entries `RTE`, PostgreSQL 14 and 15 have no `varnullingrels`,
+ * PostgreSQL 18 routes grouped columns through a group range table entry, and
+ * PostgreSQL 17 is what Supabase projects run, so each of them must resolve the
+ * same columns as non-null.
  */
 const SCHEMA = /* SQL */ `
   create schema private;
@@ -71,7 +72,7 @@ const nullability = (metadata: GeneratorMetadata, view: string) =>
       .map((column) => [column.name, column.is_nullable]),
   );
 
-describe.each(["15", "17", "18"])(
+describe.each(["14", "15", "17", "18"])(
   "view column nullability (PostgreSQL %s)",
   (version) => {
     let container: StartedPostgreSqlContainer;

packages/postgrest-typegen/test/parity/parity.test.ts

@@ -39,39 +39,50 @@ const FIXTURE_DIR = join(import.meta.dir, "..", "introspection", "fixtures");
 const EXPECTED_DIR = join(import.meta.dir, "expected");
 const golden = (name: string) => readFileSync(join(EXPECTED_DIR, name), "utf8");
 
-let container: StartedPostgreSqlContainer;
-let pool: Pool;
-let metadata: GeneratorMetadata;
+/**
+ * PostgreSQL 14 is the oldest version this package supports, matching the
+ * oldest `db.major_version` the Supabase CLI accepts. The goldens hold on it
+ * as well, so an introspection query that reads a newer catalog column, or a
+ * query tree walk that misreads its node trees, fails here.
+ */
+const MINIMUM_POSTGRES_VERSION = "14";
+
+describe.each([MINIMUM_POSTGRES_VERSION, "15"])(
+  "generator parity vs postgres-meta CLI (PostgreSQL %s)",
+  (version) => {
+    let container: StartedPostgreSqlContainer;
+    let pool: Pool;
+    let metadata: GeneratorMetadata;
 
-beforeAll(async () => {
-  container = await new PostgreSqlContainer("postgres:15-alpine")
-    .withUsername("postgres")
-    .withPassword("postgres")
-    .withDatabase("postgres")
-    .withWaitStrategy(Wait.forHealthCheck())
-    .withStartupTimeout(120_000)
-    .start();
-  pool = new Pool({ connectionString: container.getConnectionUri() });
-  await pool.query(readFileSync(join(FIXTURE_DIR, "00-init.sql"), "utf8"));
-  await pool.query(readFileSync(join(FIXTURE_DIR, "01-memes.sql"), "utf8"));
-  metadata = sortGeneratorMetadata(await introspect(pool));
-}, 180_000);
+    beforeAll(async () => {
+      container = await new PostgreSqlContainer(`postgres:${version}-alpine`)
+        .withUsername("postgres")
+        .withPassword("postgres")
+        .withDatabase("postgres")
+        .withWaitStrategy(Wait.forHealthCheck())
+        .withStartupTimeout(120_000)
+        .start();
+      pool = new Pool({ connectionString: container.getConnectionUri() });
+      await pool.query(readFileSync(join(FIXTURE_DIR, "00-init.sql"), "utf8"));
+      await pool.query(readFileSync(join(FIXTURE_DIR, "01-memes.sql"), "utf8"));
+      metadata = sortGeneratorMetadata(await introspect(pool));
+    }, 180_000);
 
-afterAll(async () => {
-  await pool?.end();
-  await container?.stop();
-});
+    afterAll(async () => {
+      await pool?.end();
+      await container?.stop();
+    });
 
-describe("generator parity vs postgres-meta CLI", () => {
-  test("typescript", async () => {
-    expect(await generateTypescript(metadata)).toBe(golden("typescript.txt"));
-  });
+    test("typescript", async () => {
+      expect(await generateTypescript(metadata)).toBe(golden("typescript.txt"));
+    });
 
-  test("go", () => {
-    expect(generateGo(metadata)).toBe(golden("go.txt"));
-  });
+    test("go", () => {
+      expect(generateGo(metadata)).toBe(golden("go.txt"));
+    });
 
-  test("python", () => {
-    expect(generatePython(metadata)).toBe(golden("python.txt"));
-  });
-});
+    test("python", () => {
+      expect(generatePython(metadata)).toBe(golden("python.txt"));
+    });
+  },
+);