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incendialincendial
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feat: add prefer last rule (#504)
* feat: add prefer last rule * test: update tests * fix: add rule to rules factory
1 parent 2290380 commit 4475714

20 files changed

+846
-49
lines changed

‎CHANGELOG.md‎

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@@ -2,7 +2,7 @@
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## Unreleased
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5-
* feat: add static code diagnostic `prefer-correct-type-name`.
5+
* feat: add static code diagnostics `prefer-correct-type-name`, `prefer-last`.
66
* chore: deprecate documentation in Github repo.
77
* chore: restrict `analyzer` version to `>=2.4.0 <2.7.0`.
88

‎lib/src/analyzers/lint_analyzer/rules/dart_rule_utils.dart‎

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import 'package:analyzer/dart/element/type.dart';
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bool isIterableOrSubclass(DartType? type) =>
4+
_isIterable(type) || _isSubclassOfIterable(type);
5+
6+
bool _isIterable(DartType? type) => type?.isDartCoreIterable ?? false;
7+
8+
bool _isSubclassOfIterable(DartType? type) =>
9+
type is InterfaceType && type.allSupertypes.any(_isIterable);
10+
11+
bool isListOrSubclass(DartType? type) =>
12+
_isList(type) || _isSubclassOfList(type);
13+
14+
bool _isList(DartType? type) => type?.isDartCoreList ?? false;
15+
16+
bool _isSubclassOfList(DartType? type) =>
17+
type is InterfaceType && type.allSupertypes.any(_isList);

‎lib/src/analyzers/lint_analyzer/rules/rules_factory.dart‎

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Original file line numberDiff line numberDiff line change
@@ -27,6 +27,7 @@ import 'rules_list/prefer_correct_type_name/prefer_correct_type_name.dart';
2727
import 'rules_list/prefer_extracting_callbacks/prefer_extracting_callbacks.dart';
2828
import 'rules_list/prefer_first/prefer_first.dart';
2929
import 'rules_list/prefer_intl_name/prefer_intl_name.dart';
30+
import 'rules_list/prefer_last/prefer_last.dart';
3031
import 'rules_list/prefer_match_file_name/prefer_match_file_name.dart';
3132
import 'rules_list/prefer_on_push_cd_strategy/prefer_on_push_cd_strategy.dart';
3233
import 'rules_list/prefer_single_widget_per_file/prefer_single_widget_per_file.dart';
@@ -77,6 +78,7 @@ final _implementedRules = <String, Rule Function(Map<String, Object>)>{
7778
PreferExtractingCallbacksRule(config),
7879
PreferFirstRule.ruleId: (config) => PreferFirstRule(config),
7980
PreferIntlNameRule.ruleId: (config) => PreferIntlNameRule(config),
81+
PreferLastRule.ruleId: (config) => PreferLastRule(config),
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PreferMatchFileName.ruleId: (config) => PreferMatchFileName(config),
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PreferOnPushCdStrategyRule.ruleId: (config) =>
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PreferOnPushCdStrategyRule(config),

‎lib/src/analyzers/lint_analyzer/rules/rules_list/prefer_first/prefer_first.dart‎

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@@ -1,13 +1,13 @@
11
import 'package:analyzer/dart/ast/ast.dart';
22
import 'package:analyzer/dart/ast/visitor.dart';
3-
import 'package:analyzer/dart/element/type.dart';
43

54
import '../../../../../utils/node_utils.dart';
65
import '../../../lint_utils.dart';
76
import '../../../models/internal_resolved_unit_result.dart';
87
import '../../../models/issue.dart';
98
import '../../../models/replacement.dart';
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import '../../../models/severity.dart';
10+
import '../../dart_rule_utils.dart';
1111
import '../../models/common_rule.dart';
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import '../../models/rule_documentation.dart';
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import '../../rule_utils.dart';
@@ -17,7 +17,7 @@ part 'visitor.dart';
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class PreferFirstRule extends CommonRule {
1818
static const ruleId = 'prefer-first';
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static const _warningMessage =
20-
'Use first instead of access to element at zero index.';
20+
'Use first instead of accessing the element at zero index.';
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static const _replaceComment = "Replace with 'first'.";
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2323
PreferFirstRule([Map<String, Object> config = const {}])

‎lib/src/analyzers/lint_analyzer/rules/rules_list/prefer_first/visitor.dart‎

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@@ -9,7 +9,7 @@ class _Visitor extends RecursiveAstVisitor<void> {
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void visitMethodInvocation(MethodInvocation node) {
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super.visitMethodInvocation(node);
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12-
if (_isIterableOrSubclass(node.realTarget?.staticType) &&
12+
if (isIterableOrSubclass(node.realTarget?.staticType) &&
1313
node.methodName.name == 'elementAt') {
1414
final arg = node.argumentList.arguments.first;
1515

@@ -23,28 +23,12 @@ class _Visitor extends RecursiveAstVisitor<void> {
2323
void visitIndexExpression(IndexExpression node) {
2424
super.visitIndexExpression(node);
2525

26-
if (_isListOrSubclass(node.realTarget.staticType)) {
26+
if (isListOrSubclass(node.realTarget.staticType)) {
2727
final index = node.index;
2828

2929
if (index is IntegerLiteral && index.value == 0) {
3030
_expressions.add(node);
3131
}
3232
}
3333
}
34-
35-
bool _isIterableOrSubclass(DartType? type) =>
36-
_isIterable(type) || _isSubclassOfIterable(type);
37-
38-
bool _isIterable(DartType? type) => type?.isDartCoreIterable ?? false;
39-
40-
bool _isSubclassOfIterable(DartType? type) =>
41-
type is InterfaceType && type.allSupertypes.any(_isIterable);
42-
43-
bool _isListOrSubclass(DartType? type) =>
44-
_isList(type) || _isSubclassOfList(type);
45-
46-
bool _isList(DartType? type) => type?.isDartCoreList ?? false;
47-
48-
bool _isSubclassOfList(DartType? type) =>
49-
type is InterfaceType && type.allSupertypes.any(_isList);
5034
}

‎lib/src/analyzers/lint_analyzer/rules/rules_list/prefer_last/prefer_last.dart‎

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import 'package:analyzer/dart/ast/ast.dart';
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import 'package:analyzer/dart/ast/token.dart';
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import 'package:analyzer/dart/ast/visitor.dart';
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5+
import '../../../../../utils/node_utils.dart';
6+
import '../../../lint_utils.dart';
7+
import '../../../models/internal_resolved_unit_result.dart';
8+
import '../../../models/issue.dart';
9+
import '../../../models/replacement.dart';
10+
import '../../../models/severity.dart';
11+
import '../../dart_rule_utils.dart';
12+
import '../../models/common_rule.dart';
13+
import '../../models/rule_documentation.dart';
14+
import '../../rule_utils.dart';
15+
16+
part 'visitor.dart';
17+
18+
class PreferLastRule extends CommonRule {
19+
static const ruleId = 'prefer-last';
20+
static const _warningMessage =
21+
'Use last instead of accessing the last element by index.';
22+
static const _replaceComment = "Replace with 'last'.";
23+
24+
PreferLastRule([Map<String, Object> config = const {}])
25+
: super(
26+
id: ruleId,
27+
documentation: const RuleDocumentation(
28+
name: 'Prefer last',
29+
brief: 'Use `last` to gets the last element',
30+
),
31+
severity: readSeverity(config, Severity.style),
32+
excludes: readExcludes(config),
33+
);
34+
35+
@override
36+
Iterable<Issue> check(InternalResolvedUnitResult source) {
37+
final visitor = _Visitor();
38+
39+
source.unit.visitChildren(visitor);
40+
41+
return visitor.expressions
42+
.map((expression) => createIssue(
43+
rule: this,
44+
location: nodeLocation(
45+
node: expression,
46+
source: source,
47+
withCommentOrMetadata: true,
48+
),
49+
message: _warningMessage,
50+
replacement: _createReplacement(expression),
51+
))
52+
.toList(growable: false);
53+
}
54+
55+
Replacement _createReplacement(Expression expression) {
56+
String replacement;
57+
58+
if (expression is MethodInvocation) {
59+
replacement =
60+
expression.isCascaded ? '..last' : '${expression.target ?? ''}.last';
61+
} else if (expression is IndexExpression) {
62+
replacement =
63+
expression.isCascaded ? '..last' : '${expression.target ?? ''}.last';
64+
} else {
65+
replacement = '.last';
66+
}
67+
68+
return Replacement(
69+
comment: _replaceComment,
70+
replacement: replacement,
71+
);
72+
}
73+
}

‎lib/src/analyzers/lint_analyzer/rules/rules_list/prefer_last/visitor.dart‎

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1+
part of 'prefer_last.dart';
2+
3+
class _Visitor extends RecursiveAstVisitor<void> {
4+
final _expressions = <Expression>[];
5+
6+
Iterable<Expression> get expressions => _expressions;
7+
8+
@override
9+
void visitMethodInvocation(MethodInvocation node) {
10+
super.visitMethodInvocation(node);
11+
12+
final target = node.realTarget;
13+
14+
if (isIterableOrSubclass(target?.staticType) &&
15+
node.methodName.name == 'elementAt') {
16+
final arg = node.argumentList.arguments.first;
17+
18+
if (arg is BinaryExpression &&
19+
_isLastElementAccess(arg, target.toString())) {
20+
_expressions.add(node);
21+
}
22+
}
23+
}
24+
25+
@override
26+
void visitIndexExpression(IndexExpression node) {
27+
super.visitIndexExpression(node);
28+
29+
final target = node.realTarget;
30+
31+
if (isListOrSubclass(target.staticType)) {
32+
final index = node.index;
33+
34+
if (index is BinaryExpression &&
35+
_isLastElementAccess(index, target.toString())) {
36+
_expressions.add(node);
37+
}
38+
}
39+
}
40+
41+
bool _isLastElementAccess(BinaryExpression expression, String targetName) {
42+
final left = expression.leftOperand;
43+
final right = expression.rightOperand;
44+
45+
return left is PrefixedIdentifier &&
46+
right is IntegerLiteral &&
47+
left.name == '$targetName.length' &&
48+
expression.operator.type == TokenType.MINUS &&
49+
right.value == 1;
50+
}
51+
}

‎test/analyzers/lint_analyzer/rules/rules_list/prefer_first/prefer_first_test.dart‎

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@@ -148,34 +148,34 @@ void main() {
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],
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messages: [
151-
'Use first instead of access to element at zero index.',
152-
'Use first instead of access to element at zero index.',
153-
'Use first instead of access to element at zero index.',
154-
'Use first instead of access to element at zero index.',
155-
'Use first instead of access to element at zero index.',
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'Use first instead of access to element at zero index.',
157-
'Use first instead of access to element at zero index.',
158-
'Use first instead of access to element at zero index.',
159-
'Use first instead of access to element at zero index.',
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'Use first instead of access to element at zero index.',
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'Use first instead of access to element at zero index.',
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'Use first instead of access to element at zero index.',
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'Use first instead of access to element at zero index.',
164-
'Use first instead of access to element at zero index.',
165-
'Use first instead of access to element at zero index.',
166-
'Use first instead of access to element at zero index.',
167-
'Use first instead of access to element at zero index.',
168-
'Use first instead of access to element at zero index.',
169-
'Use first instead of access to element at zero index.',
170-
'Use first instead of access to element at zero index.',
171-
'Use first instead of access to element at zero index.',
172-
'Use first instead of access to element at zero index.',
173-
'Use first instead of access to element at zero index.',
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'Use first instead of access to element at zero index.',
175-
'Use first instead of access to element at zero index.',
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'Use first instead of access to element at zero index.',
177-
'Use first instead of access to element at zero index.',
178-
'Use first instead of access to element at zero index.',
151+
'Use first instead of accessing the element at zero index.',
152+
'Use first instead of accessing the element at zero index.',
153+
'Use first instead of accessing the element at zero index.',
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'Use first instead of accessing the element at zero index.',
155+
'Use first instead of accessing the element at zero index.',
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'Use first instead of accessing the element at zero index.',
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'Use first instead of accessing the element at zero index.',
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'Use first instead of accessing the element at zero index.',
159+
'Use first instead of accessing the element at zero index.',
160+
'Use first instead of accessing the element at zero index.',
161+
'Use first instead of accessing the element at zero index.',
162+
'Use first instead of accessing the element at zero index.',
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'Use first instead of accessing the element at zero index.',
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'Use first instead of accessing the element at zero index.',
165+
'Use first instead of accessing the element at zero index.',
166+
'Use first instead of accessing the element at zero index.',
167+
'Use first instead of accessing the element at zero index.',
168+
'Use first instead of accessing the element at zero index.',
169+
'Use first instead of accessing the element at zero index.',
170+
'Use first instead of accessing the element at zero index.',
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'Use first instead of accessing the element at zero index.',
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'Use first instead of accessing the element at zero index.',
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'Use first instead of accessing the element at zero index.',
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'Use first instead of accessing the element at zero index.',
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'Use first instead of accessing the element at zero index.',
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'Use first instead of accessing the element at zero index.',
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'Use first instead of accessing the element at zero index.',
178+
'Use first instead of accessing the element at zero index.',
179179
],
180180
replacementComments: [
181181
"Replace with 'first'.",

‎test/analyzers/lint_analyzer/rules/rules_list/prefer_last/examples/double_linked_queue_example.dart‎

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import 'dart:collection';
2+
3+
const _array = [1, 2, 3, 4, 5, 6, 7, 8, 9];
4+
5+
void func() {
6+
final doubleLinkedQueue = DoubleLinkedQueue.of(_array);
7+
final doubleLinkedQueueLength = doubleLinkedQueue.length;
8+
final doubleLinkedQueueLastIndex = doubleLinkedQueue.length - 1;
9+
10+
doubleLinkedQueue.last;
11+
doubleLinkedQueue.elementAt(doubleLinkedQueue.length - 1); // LINT
12+
doubleLinkedQueue.elementAt(doubleLinkedQueue.length - 2);
13+
doubleLinkedQueue.elementAt(doubleLinkedQueueLength - 1);
14+
doubleLinkedQueue.elementAt(doubleLinkedQueueLastIndex);
15+
doubleLinkedQueue.elementAt(8);
16+
17+
doubleLinkedQueue
18+
..elementAt(doubleLinkedQueue.length - 1) // LINT
19+
..elementAt(doubleLinkedQueue.length - 2)
20+
..elementAt(doubleLinkedQueueLength - 1)
21+
..elementAt(doubleLinkedQueueLastIndex)
22+
..elementAt(8);
23+
}

‎test/analyzers/lint_analyzer/rules/rules_list/prefer_last/examples/hash_set_example.dart‎

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1+
import 'dart:collection';
2+
3+
const _array = [1, 2, 3, 4, 5, 6, 7, 8, 9];
4+
5+
void func() {
6+
final hashSet = HashSet.of(_array);
7+
final hashSetLength = hashSet.length;
8+
final hashSetLastIndex = hashSet.length - 1;
9+
10+
hashSet.last;
11+
hashSet.elementAt(hashSet.length - 1); // LINT
12+
hashSet.elementAt(hashSet.length - 2);
13+
hashSet.elementAt(hashSetLength - 1);
14+
hashSet.elementAt(hashSetLastIndex);
15+
hashSet.elementAt(8);
16+
17+
hashSet
18+
..elementAt(hashSet.length - 1) // LINT
19+
..elementAt(hashSet.length - 2)
20+
..elementAt(hashSetLength - 1)
21+
..elementAt(hashSetLastIndex)
22+
..elementAt(8);
23+
}

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