From 883b2ece7368388d76b083bf28827acde4332690 Mon Sep 17 00:00:00 2001
From: Ishank307 <ishankkumar307@gmail.com>
Date: Sun, 5 Oct 2025 11:24:49 +0530
Subject: [PATCH] Add circular type dependency detection

When creating custom types that reference each other (like type_1 has a field
of type_2, and type_2 has a field of type_1), the app should show an error
in the issues panel.

This was missing before - only table relationships were checked for circular
dependencies, not custom type field references.

Changes:
- Added checkCircularTypes function to detect type reference loops
- Added 'circular_type_dependency' translation key in English and Spanish
- Now shows proper error: 'Circular type dependency involving type X'

Fixes the issue where users could create invalid type structures without
any warning.
---
 src/i18n/locales/en.js |  1 +
 src/i18n/locales/es.js |  1 +
 src/utils/issues.js    | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 36 insertions(+)

diff --git a/src/i18n/locales/en.js b/src/i18n/locales/en.js
index a961c056e..0598c7f27 100644
--- a/src/i18n/locales/en.js
+++ b/src/i18n/locales/en.js
@@ -200,6 +200,7 @@ const en = {
       "Duplicate type fields by name '{{fieldName}}' in type '{{typeName}}'",
     duplicate_reference: "Duplicate reference by the name '{{refName}}'",
     circular_dependency: "Circular dependency involving table '{{refName}}'",
+    circular_type_dependency: "Circular type dependency involving type '{{typeName}}'",
     timeline: "Timeline",
     priority: "Priority",
     none: "None",
diff --git a/src/i18n/locales/es.js b/src/i18n/locales/es.js
index 5f8373134..814f6fd4c 100644
--- a/src/i18n/locales/es.js
+++ b/src/i18n/locales/es.js
@@ -195,6 +195,7 @@ const es = {
       "Campos de tipo duplicados por nombre '{{fieldName}}' en el tipo '{{typeName}}'",
     duplicate_reference: "Referencia duplicada con el nombre '{{refName}}'",
     circular_dependency: "Dependencia circular involucrando la tabla '{{refName}}'",
+    circular_type_dependency: "Dependencia circular de tipos involucrando el tipo '{{typeName}}'",
     timeline: "Linea del tiempo",
     priority: "Prioridad",
     none: "Ninguno",
diff --git a/src/utils/issues.js b/src/utils/issues.js
index 0553bb495..f4fd52d24 100644
--- a/src/utils/issues.js
+++ b/src/utils/issues.js
@@ -202,6 +202,7 @@ export function getIssues(diagram) {
     }
   });
 
+  // Check for circular table relationships
   const visitedTables = new Set();
 
   function checkCircularRelationships(tableId, visited = []) {
@@ -230,5 +231,38 @@ export function getIssues(diagram) {
     }
   });
 
+  // Check for circular type dependencies
+  function checkCircularTypes(typeName, visited = []) {
+    if (visited.includes(typeName)) {
+      issues.push(
+        i18n.t("circular_type_dependency", {
+          typeName: typeName,
+        }),
+      );
+      return;
+    }
+
+    const currentType = diagram.types.find((t) => t.name === typeName);
+    if (!currentType) return;
+
+    visited.push(typeName);
+
+    currentType.fields.forEach((field) => {
+      // Check if this field references another custom type
+      const referencedType = diagram.types.find((t) => t.name === field.type);
+      if (referencedType && field.type !== typeName) {
+        checkCircularTypes(field.type, [...visited]);
+      }
+    });
+  }
+
+  const visitedTypes = new Set();
+  diagram.types.forEach((type) => {
+    if (!visitedTypes.has(type.name)) {
+      visitedTypes.add(type.name);
+      checkCircularTypes(type.name);
+    }
+  });
+
   return issues;
 }