Allow EdgeDB to retry exceptions wrapped in retryable EdgeDB exceptions

This is the same thing we do with neo4j as well.

Author: CarsonF

src/core/edgedb/transaction.context.ts

@@ -1,6 +1,7 @@
 import { Injectable, OnModuleDestroy } from '@nestjs/common';
 import { AsyncLocalStorage } from 'async_hooks';
-import { Executor } from 'edgedb';
+import { EdgeDBError, Executor } from 'edgedb';
+import { getPreviousList } from '~/common';
 import { Client } from './reexports';
 
 @Injectable()
@@ -13,9 +14,31 @@ export class TransactionContext
   }
 
   async inTx<R>(fn: () => Promise<R>): Promise<R> {
-    return await this.client.transaction(async (tx) => {
-      return await this.run(tx, fn);
-    });
+    const errorMap = new WeakMap<Error, Error>();
+
+    try {
+      return await this.client.transaction(async (tx) => {
+        try {
+          return await this.run(tx, fn);
+        } catch (error) {
+          // If the error "wraps" an EdgeDB error, then
+          // throw that here and save the original.
+          // This allows EdgeDB to check if the error is retry-able.
+          // If it is, then this error doesn't matter; otherwise we'll unwrap below.
+          const maybeRetryableError = getPreviousList(error, true).find(
+            (e) => e instanceof EdgeDBError,
+          );
+          if (maybeRetryableError) {
+            errorMap.set(maybeRetryableError, error);
+            throw maybeRetryableError;
+          }
+          throw error;
+        }
+      });
+    } catch (error) {
+      // Unwrap the original error if it was wrapped above.
+      throw errorMap.get(error) ?? error;
+    }
   }
 
   get current() {