Fix for magic number lint (#137)

* Fix for magic number lint

* documentation for const class instances

* doc fix

* version change

Author: Viktor-Mudrytskyi

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## 0.1.5
 
-- Add `avoid_using_debug_print` rule
+- Added `avoid_using_debug_print` rule
+- Fixed an issue with no_magic_number lint
 
 ## 0.1.4
 

lib/src/lints/no_magic_number/no_magic_number_rule.dart

@@ -59,6 +59,14 @@ import 'package:solid_lints/src/models/solid_lint_rule.dart';
 /// bool canDrive(int age, {bool isUSA = false}) {
 ///   return isUSA ? age >= 16 : age > 18; // LINT
 /// }
+///
+/// class Circle {
+///   final int r;
+///   const Circle({required this.r});
+/// }
+/// Circle(r: 5); // LINT
+/// var circle = Circle(r: 10); // LINT
+/// final circle2 = Circle(r: 10); // LINT
 /// ```
 ///
 /// #### GOOD:
@@ -74,6 +82,13 @@ import 'package:solid_lints/src/models/solid_lint_rule.dart';
 /// bool canDrive(int age, {bool isUSA = false}) {
 ///   return isUSA ? age >= usaDrivingAge : age > worldWideDrivingAge;
 /// }
+///
+/// class Circle {
+///   final int r;
+///   const Circle({required this.r});
+/// }
+/// const Circle(r: 5);
+/// const circle = Circle(r: 10)
 /// ```
 ///
 /// ### Allowed
@@ -174,11 +189,24 @@ class NoMagicNumberRule extends SolidLintRule<NoMagicNumberParameters> {
       (l is IntegerLiteral &&
           !config.parameters.allowedNumbers.contains(l.value));
 
-  bool _isNotInsideVariable(Literal l) =>
-      l.thisOrAncestorMatching(
-        (ancestor) => ancestor is VariableDeclaration,
-      ) ==
-      null;
+  bool _isNotInsideVariable(Literal l) {
+    // Whether we encountered such node,
+    // This is tracked because [InstanceCreationExpression] can be
+    // inside [VariableDeclaration] removing unwanted literals
+
+    bool isInstanceCreationExpression = false;
+    return l.thisOrAncestorMatching((ancestor) {
+          if (ancestor is InstanceCreationExpression) {
+            isInstanceCreationExpression = true;
+          }
+          if (isInstanceCreationExpression) {
+            return false;
+          } else {
+            return ancestor is VariableDeclaration;
+          }
+        }) ==
+        null;
+  }
 
   bool _isNotInDateTime(Literal l) =>
       l.thisOrAncestorMatching(
@@ -206,10 +234,9 @@ class NoMagicNumberRule extends SolidLintRule<NoMagicNumberParameters> {
   }
 
   bool _isNotInsideConstConstructor(Literal l) =>
-      l.thisOrAncestorMatching(
-        (ancestor) =>
-            ancestor is InstanceCreationExpression && ancestor.isConst,
-      ) ==
+      l.thisOrAncestorMatching((ancestor) {
+        return ancestor is InstanceCreationExpression && ancestor.isConst;
+      }) ==
       null;
 
   bool _isNotInsideIndexExpression(Literal l) => l.parent is! IndexExpression;

lint_test/no_magic_number_test.dart

@@ -15,7 +15,7 @@ double correctCircumference(double radius) =>
     radiusToDiameterCoefficient * pi * radius;
 
 bool canDrive(int age, {bool isUSA = false}) {
-// expect_lint: no_magic_number
+  // expect_lint: no_magic_number
   return isUSA ? age >= 16 : age > 18;
 }
 
@@ -111,7 +111,39 @@ Widget build() {
   return MyWidget(
     // expect_lint: no_magic_number
     decoration: MyWidgetDecoration(size: 12),
+
     // expect_lint: no_magic_number
     value: 23,
   );
 }
+
+class TestOperation {
+  final double res;
+
+  const TestOperation({required this.res});
+}
+
+const n = 15;
+const m = 20;
+
+void checkOperationInConstructor() {
+  // expect_lint: no_magic_number
+  TestOperation(res: (5 / 5) * 20);
+
+  // expect_lint: no_magic_number
+  var variable = TestOperation(res: (n / m) * 20);
+
+  // expect_lint: no_magic_number
+  final finalVar = TestOperation(res: (10 / m + 4 + n));
+
+  // Allowed for constant expressions
+  const constVar = TestOperation(res: (10 / m + 4 + n));
+
+  var constVar2 = const TestOperation(res: 15 + (10 / n));
+
+  final l = [
+    // expect_lint: no_magic_number
+    TestOperation(res: 8),
+    const TestOperation(res: 9),
+  ];
+}