Fix infinite recursion on circular selectable dependencies

packages/schemainspect/src/pg/obj.ts

@@ -1427,16 +1427,24 @@ export class PostgreSQL extends DBInspector {
     const get_related_for_item = (
       item: InspectedSelectable | InspectedTrigger | InspectedEnum,
       att: 'dependent_on' | 'dependents',
+      visited: Set<string> = new Set(),
     ): string[] => {
+      if (visited.has(item.signature)) {
+        return []
+      }
+      visited.add(item.signature)
       const related = item[att].map((child: string) => this.get_dependency_by_signature(child))
-      return [item.signature, ...related.filter(d => d).flatMap(d => get_related_for_item(d, att))]
+      return [item.signature, ...related.filter(d => d).flatMap(d => get_related_for_item(d, att, visited))]
     }
 
     for (const [k, x] of Object.entries(this.selectables)) {
-      let d_all = get_related_for_item(x, 'dependent_on').slice(1)
+      const rootSig = x.signature
+      // Get all dependencies and remove the root item itself (first occurrence via slice(1))
+      // Then filter out any remaining occurrences of root (from circular dependencies)
+      let d_all = get_related_for_item(x, 'dependent_on').slice(1).filter(sig => sig !== rootSig)
       d_all.sort()
       x.dependent_on_all = d_all
-      d_all = get_related_for_item(x, 'dependents').slice(1)
+      d_all = get_related_for_item(x, 'dependents').slice(1).filter(sig => sig !== rootSig)
       d_all.sort()
       x.dependents_all = d_all
     }

packages/schemainspect/test/circular-deps.test.ts

@@ -0,0 +1,36 @@
+import {expect, test} from 'vitest'
+import {InspectedSelectable, PostgreSQL} from '../src/pg'
+
+function makeSelectable(name: string) {
+  return new InspectedSelectable({
+    name,
+    schema: 'public',
+    columns: {},
+    definition: '',
+    relationtype: 'v',
+    comment: '',
+  })
+}
+
+test('load_deps_all does not blow the stack on circular view dependencies', async () => {
+  const db = PostgreSQL.empty()
+
+  const a = makeSelectable('a')
+  const b = makeSelectable('b')
+
+  // Two views that depend on each other -- this can happen with e.g. matching pg_depend rows for
+  // mutually-referencing views/rules, and previously caused infinite recursion in
+  // get_related_for_item since it revisited the same signature forever.
+  a.dependent_on.push(b.signature)
+  b.dependents.push(a.signature)
+  b.dependent_on.push(a.signature)
+  a.dependents.push(b.signature)
+
+  db.selectables[a.signature] = a
+  db.selectables[b.signature] = b
+
+  await expect(db.load_deps_all()).resolves.not.toThrow()
+
+  expect(a.dependent_on_all).toEqual([b.signature])
+  expect(b.dependent_on_all).toEqual([a.signature])
+})