feat: surface expression validation errors when creating or updating rules

app/Api/V1/Controllers/Models/Rule/ExpressionController.php

@@ -74,15 +74,14 @@ class ExpressionController extends Controller
         $expressionLanguage = ExpressionLanguageFactory::get();
         $evaluator = new ActionExpressionEvaluator($expressionLanguage, $expr);
 
-        try {
-            $evaluator->lint();
+        if ($evaluator->isValid()) {
             return response()->json([
                 "valid" => true,
             ]);
-        } catch (SyntaxError $e) {
+        } else {
             return response()->json([
                 "valid" => false,
-                "error" => $e->getMessage()
+                "error" => $evaluator->getValidationError()->getMessage()
             ]);
         }
     }

app/Api/V1/Requests/Models/Rule/StoreRequest.php

@@ -123,7 +123,7 @@ class StoreRequest extends FormRequest
             'triggers.*.stop_processing' => [new IsBoolean()],
             'triggers.*.active'          => [new IsBoolean()],
             'actions.*.type'             => 'required|in:'.implode(',', $validActions),
-            'actions.*.value'            => 'required_if:actions.*.type,'.$contextActions.'|ruleActionValue',
+            'actions.*.value'            => 'required_if:actions.*.type,'.$contextActions.'|ruleActionExpression|ruleActionValue',
             'actions.*.stop_processing'  => [new IsBoolean()],
             'actions.*.active'           => [new IsBoolean()],
             'strict'                     => [new IsBoolean()],

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

@@ -140,7 +140,7 @@ class UpdateRequest extends FormRequest
             'triggers.*.stop_processing' => [new IsBoolean()],
             'triggers.*.active'          => [new IsBoolean()],
             'actions.*.type'             => 'required|in:'.implode(',', $validActions),
-            'actions.*.value'            => 'required_if:actions.*.type,'.$contextActions.'|ruleActionValue',
+            'actions.*.value'            => 'required_if:actions.*.type,'.$contextActions.'|ruleActionExpression|ruleActionValue',
             'actions.*.stop_processing'  => [new IsBoolean()],
             'actions.*.active'           => [new IsBoolean()],
             'strict'                     => [new IsBoolean()],

app/Http/Requests/RuleFormRequest.php

@@ -147,7 +147,7 @@ class RuleFormRequest extends FormRequest
             'triggers.*.type'  => 'required|in:'.implode(',', $validTriggers),
             'triggers.*.value' => sprintf('required_if:triggers.*.type,%s|max:1024|min:1|ruleTriggerValue', $contextTriggers),
             'actions.*.type'   => 'required|in:'.implode(',', $validActions),
-            'actions.*.value'  => sprintf('required_if:actions.*.type,%s|min:0|max:1024|ruleActionValue', $contextActions),
+            'actions.*.value'  => sprintf('required_if:actions.*.type,%s|min:0|max:1024|ruleActionExpression|ruleActionValue', $contextActions),
             'strict'           => 'in:0,1',
         ];
 

app/TransactionRules/Expressions/ActionExpressionEvaluator.php

@@ -31,9 +31,10 @@ class ActionExpressionEvaluator
 {
     private static array $NAMES = array("transaction");
 
+    private ExpressionLanguage $expressionLanguage;
     private string $expr;
     private bool $isExpression;
-    private ExpressionLanguage $expressionLanguage;
+    private ?SyntaxError $validationError;
 
     public function __construct(ExpressionLanguage $expressionLanguage, string $expr)
     {
@@ -41,6 +42,7 @@ class ActionExpressionEvaluator
         $this->expr = $expr;
 
         $this->isExpression = self::isExpression($expr);
+        $this->validationError = $this->validate();
     }
 
     private static function isExpression(string $expr): bool
@@ -48,17 +50,17 @@ class ActionExpressionEvaluator
         return str_starts_with($expr, "=");
     }
 
-    public function isValid(): bool
+    private function validate(): ?SyntaxError
     {
         if (!$this->isExpression) {
-            return true;
+            return null;
         }
 
         try {
-            $this->lint(array());
-            return true;
+            $this->lint();
+            return null;
         } catch (SyntaxError $e) {
-            return false;
+            return $e;
         }
     }
 
@@ -67,7 +69,7 @@ class ActionExpressionEvaluator
         $this->expressionLanguage->lint($expr, self::$NAMES);
     }
 
-    public function lint(): void
+    private function lint(): void
     {
         if (!$this->isExpression) {
             return;
@@ -76,6 +78,16 @@ class ActionExpressionEvaluator
         $this->lintExpression(substr($this->expr, 1));
     }
 
+    public function isValid(): bool
+    {
+        return $this->validationError === null;
+    }
+
+    public function getValidationError()
+    {
+        return $this->validationError;
+    }
+
     private function evaluateExpression(string $expr, array $journal): string
     {
         $result = $this->expressionLanguage->evaluate($expr, [

app/Validation/FireflyValidator.php

@@ -35,6 +35,8 @@ use FireflyIII\Repositories\Budget\BudgetRepositoryInterface;
 use FireflyIII\Repositories\PiggyBank\PiggyBankRepositoryInterface;
 use FireflyIII\Services\Password\Verifier;
 use FireflyIII\Support\ParseDateString;
+use FireflyIII\TransactionRules\Expressions\ActionExpressionEvaluator;
+use FireflyIII\TransactionRules\Factory\ExpressionLanguageFactory;
 use FireflyIII\User;
 use Illuminate\Validation\Validator;
 use PragmaRX\Google2FA\Exceptions\IncompatibleWithGoogleAuthenticatorException;
@@ -253,6 +255,31 @@ class FireflyValidator extends Validator
         return 1 === $count;
     }
 
+    public function validateRuleActionExpression(string $attribute, string $value = null): bool
+    {
+        $value ??= '';
+
+        $el = ExpressionLanguageFactory::get();
+        $evaluator = new ActionExpressionEvaluator($el, $value);
+
+        return $evaluator->isValid();
+    }
+
+    public function replaceRuleActionExpression(string $message, string $attribute): string
+    {
+        $value = $this->getValue($attribute);
+
+        $el = ExpressionLanguageFactory::get();
+        $evaluator = new ActionExpressionEvaluator($el, $value);
+        $err = $evaluator->getValidationError();
+
+        if ($err == null) {
+            return $message;
+        }
+
+        return str_replace(":error", $err->getMessage(), $message);
+    }
+
     public function validateRuleActionValue(string $attribute, string $value = null): bool
     {
         // first, get the index from this string:
@@ -268,6 +295,11 @@ class FireflyValidator extends Validator
             return false;
         }
 
+        // if value is an expression, assume valid
+        if (str_starts_with($value, '=')) {
+            return true;
+        }
+
         // if it's set_budget, verify the budget name:
         if ('set_budget' === $actionType) {
             /** @var BudgetRepositoryInterface $repository */

resources/lang/en_US/validation.php

@@ -46,6 +46,7 @@ return [
     'reconciled_forbidden_field'      => 'This transaction is already reconciled, you cannot change the ":field"',
     'deleted_user'                    => 'Due to security constraints, you cannot register using this email address.',
     'rule_trigger_value'              => 'This value is invalid for the selected trigger.',
+    'rule_action_expression'          => 'Invalid expression. :error',
     'rule_action_value'               => 'This value is invalid for the selected action.',
     'file_already_attached'           => 'Uploaded file ":name" is already attached to this object.',
     'file_attached'                   => 'Successfully uploaded file ":name".',