fix(syncedinstance): Prevent same-instance syncs and sanitize post update payloads; update tests and docs

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@apiclient.xyz/ghost',
-  version: '2.2.0',
+  version: '2.2.1',
   description: 'An unofficial Ghost CMS API package enabling content and admin functionality for managing posts.'
 }

ts/classes.post.ts

@@ -118,9 +118,34 @@ export class Post {
     return this.postData;
   }
 
-  public async update(postData: IPost): Promise<Post> {
+  public async update(postData: Partial<IPost>): Promise<Post> {
     try {
-      const updatedPostData = await this.ghostInstanceRef.adminApi.posts.edit(postData);
+      // Only send fields that should be updated, not the entire post object with nested relations
+      const updatePayload: any = {
+        id: this.postData.id,
+        updated_at: this.postData.updated_at, // Required for conflict detection
+        ...postData
+      };
+
+      // Remove read-only or computed fields that shouldn't be sent
+      delete updatePayload.uuid;
+      delete updatePayload.comment_id;
+      delete updatePayload.url;
+      delete updatePayload.excerpt;
+      delete updatePayload.reading_time;
+      delete updatePayload.created_at; // Don't send created_at in updates
+      delete updatePayload.primary_author;
+      delete updatePayload.primary_tag;
+      delete updatePayload.count;
+      delete updatePayload.email;
+      delete updatePayload.newsletter;
+
+      // Remove nested objects if they're not being updated
+      if (!postData.authors) delete updatePayload.authors;
+      if (!postData.tags) delete updatePayload.tags;
+      if (!postData.tiers) delete updatePayload.tiers;
+
+      const updatedPostData = await this.ghostInstanceRef.adminApi.posts.edit(updatePayload);
       this.postData = updatedPostData;
       return this;
     } catch (error) {

ts/classes.syncedinstance.ts

@@ -50,6 +50,20 @@ export class SyncedInstance {
   private syncHistory: ISyncReport[];
 
   constructor(sourceGhost: Ghost, targetGhosts: Ghost[]) {
+    // Validate that no target instance is the same as the source instance
+    const sourceUrl = sourceGhost.options.baseUrl.replace(/\/$/, '').toLowerCase();
+
+    for (const targetGhost of targetGhosts) {
+      const targetUrl = targetGhost.options.baseUrl.replace(/\/$/, '').toLowerCase();
+
+      if (sourceUrl === targetUrl) {
+        throw new Error(
+          `Cannot sync to the same instance. Source and target both point to: ${sourceUrl}. ` +
+          `This would create a circular sync and cause excessive API calls.`
+        );
+      }
+    }
+
     this.sourceGhost = sourceGhost;
     this.targetGhosts = targetGhosts;
     this.syncMappings = new Map();
@@ -125,6 +139,7 @@ export class SyncedInstance {
             if (!optionsArg?.dryRun) {
               await targetTag.update({
                 name: sourceTag.name,
+                slug: sourceTag.slug,
                 description: sourceTag.description,
                 feature_image: sourceTag.feature_image,
                 visibility: sourceTag.visibility,