Add block record duplicate detection (bluesky-social#1027)

* Add block record duplicate detection

* Update packages/pds/src/services/record/index.ts

---------

Co-authored-by: Daniel Holmgren <[email protected]>

Author: Matrix89

packages/pds/src/api/com/atproto/repo/createRecord.ts

@@ -96,7 +96,8 @@ async function getBacklinkDeletions(
     prepareDelete({ did, collection, rkey })
 
   if (
-    collection === ids.AppBskyGraphFollow &&
+    (collection === ids.AppBskyGraphFollow ||
+      collection === ids.AppBskyGraphBlock) &&
     typeof record['subject'] === 'string'
   ) {
     const backlinks = await recordTxn.getRecordBacklinks({

packages/pds/src/services/record/index.ts

@@ -278,10 +278,13 @@ export class RecordService {
 }
 
 // @NOTE in the future this can be replaced with a more generic routine that pulls backlinks based on lex docs.
-// For now we just want to ensure we're tracking links from follows, likes, and reposts.
+// For now we just want to ensure we're tracking links from follows, blocks, likes, and reposts.
 
 function getBacklinks(uri: AtUri, record: unknown): Backlink[] {
-  if (record?.['$type'] === ids.AppBskyGraphFollow) {
+  if (
+    record?.['$type'] === ids.AppBskyGraphFollow ||
+    record?.['$type'] === ids.AppBskyGraphBlock
+  ) {
     const subject = record['subject']
     if (typeof subject !== 'string') {
       return []

packages/pds/tests/crud.test.ts

@@ -979,6 +979,68 @@ describe('crud operations', () => {
     await expect(getRepost3).resolves.toBeDefined()
   })
 
+  it('prevents duplicate blocks', async () => {
+    const now = new Date().toISOString()
+
+    const { data: block1 } = await aliceAgent.api.com.atproto.repo.createRecord(
+      {
+        repo: alice.did,
+        collection: 'app.bsky.graph.block',
+        record: {
+          $type: 'app.bsky.graph.block',
+          subject: bob.did,
+          createdAt: now,
+        },
+      },
+    )
+
+    const { data: block2 } = await bobAgent.api.com.atproto.repo.createRecord({
+      repo: bob.did,
+      collection: 'app.bsky.graph.block',
+      record: {
+        $type: 'app.bsky.graph.block',
+        subject: alice.did,
+        createdAt: now,
+      },
+    })
+
+    const { data: block3 } = await aliceAgent.api.com.atproto.repo.createRecord(
+      {
+        repo: alice.did,
+        collection: 'app.bsky.graph.block',
+        record: {
+          $type: 'app.bsky.graph.block',
+          subject: bob.did,
+          createdAt: now,
+        },
+      },
+    )
+
+    const getBlock1 = aliceAgent.api.com.atproto.repo.getRecord({
+      repo: alice.did,
+      collection: 'app.bsky.graph.block',
+      rkey: new AtUri(block1.uri).rkey,
+    })
+
+    await expect(getBlock1).rejects.toThrow('Could not locate record:')
+
+    const getBlock2 = aliceAgent.api.com.atproto.repo.getRecord({
+      repo: bob.did,
+      collection: 'app.bsky.graph.block',
+      rkey: new AtUri(block2.uri).rkey,
+    })
+
+    await expect(getBlock2).resolves.toBeDefined()
+
+    const getBlock3 = aliceAgent.api.com.atproto.repo.getRecord({
+      repo: alice.did,
+      collection: 'app.bsky.graph.block',
+      rkey: new AtUri(block3.uri).rkey,
+    })
+
+    await expect(getBlock3).resolves.toBeDefined()
+  })
+
   it('prevents duplicate follows', async () => {
     const now = new Date().toISOString()