Verify routine will check currency usage.

app/Console/Commands/VerifyDatabase.php

@@ -28,12 +28,15 @@ namespace FireflyIII\Console\Commands;
 use Crypt;
 use DB;
 use FireflyIII\Models\Account;
+use FireflyIII\Models\AccountMeta;
 use FireflyIII\Models\AccountType;
 use FireflyIII\Models\Budget;
+use FireflyIII\Models\BudgetLimit;
 use FireflyIII\Models\Category;
 use FireflyIII\Models\LinkType;
 use FireflyIII\Models\PiggyBankEvent;
 use FireflyIII\Models\Transaction;
+use FireflyIII\Models\TransactionCurrency;
 use FireflyIII\Models\TransactionJournal;
 use FireflyIII\Models\TransactionType;
 use FireflyIII\Repositories\User\UserRepositoryInterface;
@@ -41,6 +44,7 @@ use FireflyIII\User;
 use Illuminate\Console\Command;
 use Illuminate\Contracts\Encryption\DecryptException;
 use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Support\Collection;
 use Log;
 use Schema;
 use stdClass;
@@ -95,6 +99,7 @@ class VerifyDatabase extends Command
         $this->fixDoubleAmounts();
         $this->fixBadMeta();
         $this->removeBills();
+        $this->enableCurrencies();
 
         return 0;
     }
@@ -150,6 +155,45 @@ class VerifyDatabase extends Command
         }
     }
 
+    /**
+     * Will make sure that all currencies in use are actually enabled.
+     */
+    private function enableCurrencies(): void
+    {
+        $found = [];
+        // get all meta entries
+        /** @var Collection $meta */
+        $meta = AccountMeta::where('name', 'currency_id')->groupBy('data')->get(['data']);
+        foreach ($meta as $entry) {
+            $found[] = (int)$entry->data;
+        }
+
+        // get all from journals:
+        /** @var Collection $journals */
+        $journals = TransactionJournal::groupBy('transaction_currency_id')->get(['transaction_currency_id']);
+        foreach ($journals as $entry) {
+            $found[] = (int)$entry->transaction_currency_id;
+        }
+
+        // get all from transactions
+        /** @var Collection $transactions */
+        $transactions = Transaction::groupBy('transaction_currency_id')->get(['transaction_currency_id']);
+        foreach ($transactions as $entry) {
+            $found[] = (int)$entry->transaction_currency_id;
+        }
+
+        // get all from budget limits
+        /** @var Collection $limits */
+        $limits = BudgetLimit::groupBy('transaction_currency_id')->get(['transaction_currency_id']);
+        foreach ($limits as $entry) {
+            $found[] = (int)$entry->transaction_currency_id;
+        }
+
+        $found = array_unique($found);
+        TransactionCurrency::whereIn('id', $found)->update(['enabled' => true]);
+
+    }
+
     /**
      * Fix the situation where the matching transactions of a journal somehow have non-matching categories or budgets.
      *

app/Models/TransactionCurrency.php

@@ -95,4 +95,13 @@ class TransactionCurrency extends Model
     {
         return $this->hasMany(Transaction::class);
     }
+
+    /**
+     * @codeCoverageIgnore
+     * @return HasMany
+     */
+    public function budgetLimits(): HasMany
+    {
+        return $this->hasMany(BudgetLimit::class);
+    }
 }

app/Repositories/Currency/CurrencyRepository.php

@@ -25,6 +25,7 @@ namespace FireflyIII\Repositories\Currency;
 use Carbon\Carbon;
 use FireflyIII\Factory\TransactionCurrencyFactory;
 use FireflyIII\Models\AccountMeta;
+use FireflyIII\Models\BudgetLimit;
 use FireflyIII\Models\CurrencyExchangeRate;
 use FireflyIII\Models\Preference;
 use FireflyIII\Models\TransactionCurrency;
@@ -93,6 +94,14 @@ class CurrencyRepository implements CurrencyRepositoryInterface
             return true;
         }
 
+        // is being used in budget limits
+        $budgetLimit = BudgetLimit::where('transaction_currency_id', $currency->id)->count();
+        if ($budgetLimit > 0) {
+            Log::debug(sprintf('Used in %d budget limits as currency, return true. ', $budgetLimit));
+
+            return true;
+        }
+
         // is the default currency for the user or the system
         $defaultCode = app('preferences')->getForUser($this->user, 'currencyPreference', config('firefly.default_currency', 'EUR'))->data;
         if ($currency->code === $defaultCode) {