fix(selfhost): translate json_each() array iteration for Postgres

src/selfhost/pg-dialect.ts

@@ -88,6 +88,13 @@ export function translateFunctions(sql: string): string {
       .replace(/json_extract\(\s*([^,]+?)\s*,\s*'\$\.((?:[A-Za-z0-9_]+\.)+[A-Za-z0-9_]+)'\s*\)/gi, (_m, col, path) => `((${col})::jsonb #>> '{${path.split(".").join(",")}}')`)
       // json_extract(col, '$.key') → (col::jsonb ->> 'key')  (single-level paths)
       .replace(/json_extract\(\s*([^,]+?)\s*,\s*'\$\.([A-Za-z0-9_]+)'\s*\)/gi, `(($1)::jsonb ->> '$2')`)
+      // json_each(col) alias → SQLite's json_each() on a JSON ARRAY yields one row per element with a
+      // `value` column (migrations/0191's linked-issue-claims backfill reads je.value); untranslated on
+      // Postgres, json_each() there decomposes JSON OBJECTS only and rejects a bare TEXT column outright
+      // ("function json_each(text) does not exist"), crash-looping the self-host Postgres migration runner
+      // on startup. json_array_elements_text is Postgres's array-expansion equivalent — cast the column to
+      // `json` and alias the single output column back to `value` so `je.value` keeps working unchanged.
+      .replace(/\bjson_each\(\s*([^()]+?)\s*\)\s*(?:AS\s+)?([A-Za-z_][A-Za-z0-9_]*)\b/gi, (_m, col, alias) => `json_array_elements_text((${col})::json) AS ${alias}(value)`)
       // instr(haystack, needle) → strpos(haystack, needle): both are 1-based first-occurrence index, 0 if
       // absent -- a direct semantic match, no formula adjustment needed. Postgres has no `instr` builtin at
       // all (unlike substr, which is SQL-standard and needs no translation) -- every instr() call reaching

test/unit/selfhost-pg-dialect.test.ts

@@ -46,6 +46,30 @@ describe("pg-dialect (#977 SQLite → Postgres)", () => {
     expect(translateFunctions("candidate(x)")).toBe("candidate(x)");
   });
 
+  it("REGRESSION: translates json_each(col) array iteration to json_array_elements_text (crash-looped self-host Postgres boot, beta.9)", () => {
+    // migrations/0191_linked_issue_claims.sql's backfill reads je.value after `FROM pull_requests pr,
+    // json_each(pr.linked_issues_json) je` — untranslated, Postgres's own json_each() only accepts JSON
+    // OBJECTS (and rejects a TEXT column outright: "function json_each(text) does not exist"), which crashed
+    // the self-host Postgres migration runner in a boot loop in production. json_array_elements_text is the
+    // array-expansion equivalent; the column alias list `(value)` keeps `je.value` readable unchanged.
+    expect(translateFunctions("json_each(pr.linked_issues_json) je")).toBe("json_array_elements_text((pr.linked_issues_json)::json) AS je(value)");
+    // The bare (no `AS`) alias form is what the migration actually uses; the `AS` form must also translate.
+    expect(translateFunctions("json_each(col) AS alias")).toBe("json_array_elements_text((col)::json) AS alias(value)");
+    expect(
+      translateDdl(
+        "INSERT INTO linked_issue_claims (repo_full_name, pull_number, issue_number, claimed_at)\n" +
+          "SELECT pr.repo_full_name, pr.number, CAST(je.value AS INTEGER), pr.updated_at\n" +
+          "FROM pull_requests pr, json_each(pr.linked_issues_json) je\n" +
+          "WHERE pr.linked_issues_json != '[]';",
+      ),
+    ).toBe(
+      "INSERT INTO linked_issue_claims (repo_full_name, pull_number, issue_number, claimed_at)\n" +
+        "SELECT pr.repo_full_name, pr.number, CAST(je.value AS INTEGER), pr.updated_at\n" +
+        "FROM pull_requests pr, json_array_elements_text((pr.linked_issues_json)::json) AS je(value)\n" +
+        "WHERE pr.linked_issues_json != '[]';",
+    );
+  });
+
   it("REGRESSION: translates instr(haystack, needle) to Postgres's strpos (SQLite has no `instr` on Postgres)", () => {
     expect(translateFunctions("instr(x, '#')")).toBe("strpos(x, '#')");
     expect(translateFunctions("instr(ra.target_id, '#') > 0")).toBe("strpos(ra.target_id, '#') > 0");