Code for https://github.com/firefly-iii/firefly-iii/issues/5610

app/Api/V1/Requests/Models/Transaction/UpdateRequest.php

@@ -292,6 +292,10 @@ class UpdateRequest extends FormRequest
             'transactions.*.date'                  => [new IsDateOrTime],
             'transactions.*.order'                 => 'numeric|min:0',
 
+            // group id:
+            'transactions.*.transaction_journal_id'           => ['numeric','exists:transaction_journals,id', new BelongsUser],
+
+
             // currency info
             'transactions.*.currency_id'           => 'numeric|exists:transaction_currencies,id',
             'transactions.*.currency_code'         => 'min:3|max:3|exists:transaction_currencies,code',
@@ -375,6 +379,9 @@ class UpdateRequest extends FormRequest
                 // validate source/destination is equal, depending on the transaction journal type.
                 $this->validateEqualAccountsForUpdate($validator, $transactionGroup);
 
+                // a catch when users submit splits with no source or destination info at all.
+                $this->preventNoAccountInfo($validator,);
+
                 // validate that the currency fits the source and/or destination account.
                 // validate all account info
                 $this->validateAccountInformationUpdate($validator, $transactionGroup);

app/Handlers/Events/UpdatedGroupEventHandler.php

@@ -131,6 +131,12 @@ class UpdatedGroupEventHandler
                        ->orderBy('transaction_journals.id', 'DESC')
                        ->orderBy('transaction_journals.description', 'DESC')
                        ->first();
+
+        if(null === $first) {
+            Log::warning(sprintf('Group #%d has no transaction journals.', $group->id));
+            return;
+        }
+
         $all   = $group->transactionJournals()->get()->pluck('id')->toArray();
         /** @var Account $sourceAccount */
         $sourceAccount = $first->transactions()->where('amount', '<', '0')->first()->account;

app/Rules/BelongsUser.php

@@ -30,6 +30,7 @@ use FireflyIII\Models\Bill;
 use FireflyIII\Models\Budget;
 use FireflyIII\Models\Category;
 use FireflyIII\Models\PiggyBank;
+use FireflyIII\Models\TransactionJournal;
 use Illuminate\Contracts\Validation\Rule;
 use Log;
 
@@ -83,6 +84,7 @@ class BelongsUser implements Rule
             'piggy_bank_id' => $this->validatePiggyBankId((int)$value),
             'piggy_bank_name' => $this->validatePiggyBankName($value),
             'bill_id' => $this->validateBillId((int)$value),
+            'transaction_journal_id' => $this->validateJournalId((int)$value),
             'bill_name' => $this->validateBillName($value),
             'budget_id' => $this->validateBudgetId((int)$value),
             'category_id' => $this->validateCategoryId((int)$value),
@@ -185,6 +187,21 @@ class BelongsUser implements Rule
         return 1 === $count;
     }
 
+    /**
+     * @param int $value
+     *
+     * @return bool
+     */
+    private function validateJournalId(int $value): bool
+    {
+        if (0 === $value) {
+            return true;
+        }
+        $count = TransactionJournal::where('id', '=', $value)->where('user_id', '=', auth()->user()->id)->count();
+
+        return 1 === $count;
+    }
+
     /**
      * @param string $value
      *

app/Validation/GroupValidation.php

@@ -83,6 +83,30 @@ trait GroupValidation
         }
     }
 
+    protected function preventNoAccountInfo(Validator $validator): void
+    {
+        $transactions   = $this->getTransactionsArray($validator);
+        $hasAccountInfo = false;
+        $keys           = ['source_id', 'destination_id', 'source_name', 'destination_name', 'source_iban', 'destination_iban', 'source_number',
+                           'destination_number'];
+        /** @var array $transaction */
+        foreach ($transactions as $transaction) {
+            foreach($keys as $key) {
+                if(array_key_exists($key, $transaction) && '' !== $transaction[$key]) {
+                    $hasAccountInfo = true;
+                }
+            }
+        }
+        if(false === $hasAccountInfo) {
+            $validator->errors()->add(
+                'transactions.0.source_id', (string)trans('validation.generic_no_source')
+            );
+            $validator->errors()->add(
+                'transactions.0.destination_id', (string)trans('validation.generic_no_destination')
+            );
+        }
+    }
+
     /**
      * This method validates if the user has submitted transaction journal ID's for each array they submit, if they've submitted more than 1 transaction
      * journal. This check is necessary because Firefly III isn't able to distinguish between journals without the ID.

resources/lang/en_US/validation.php

@@ -214,6 +214,9 @@ return [
     'generic_invalid_source'      => 'You can\'t use this account as the source account.',
     'generic_invalid_destination' => 'You can\'t use this account as the destination account.',
 
+    'generic_no_source'      => 'You must submit source account information.',
+    'generic_no_destination' => 'You must submit destination account information.',
+
     'gte.numeric' => 'The :attribute must be greater than or equal to :value.',
     'gt.numeric'  => 'The :attribute must be greater than :value.',
     'gte.file'    => 'The :attribute must be greater than or equal to :value kilobytes.',