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Custom Lint Rules

Игорь Таланкин

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О чем доклад?

Статический анализ
Android Lint
Custom lint rules

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Статический анализ

стилистика

отступы, форматирование

семантика

ошибки в логике, недостижимые участки кода

подсчет метрик

Source Lines Of Code, количество комментариев, сложность

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Android Lint

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Android Lint

статический анализатор кода
работает в IDE из коробки
мультидисциплинарный

XML, Java, Kotlin, JPEG, Properties, etc.

можно поставлять вместе с библиотеками

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Timber

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$ ./gradlew lint

Ran lint on variant debug: 2 issues found

Ran lint on variant release: 1 issues found

Wrote HTML report to file:///.../build/reports/lint-results.html

Wrote XML report to file:///.../build/reports/lint-results.xml

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<?xml version="1.0" encoding="UTF-8"?>

<issue

id="UnusedResources"

severity="Warning"

message="`R.layout.unused_layout` appears to be unused"

category="Performance"

priority="3"

summary="Unused resources"

explanation="..."

errorLine1="<LinearLayout"

errorLine2="^">

<location

file="/.../unused_layout.xml"

line="2"

column="1"/>

</issue>

</issues>

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HTML

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IDE

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android {

lintOptions {

baseline file('baseline.xml')

checkDependencies true

}

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android {

lintOptions {

baseline file('baseline.xml')

checkDependencies true

}

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android {

lintOptions {

baseline file('baseline.xml')

checkDependencies true

}

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Custom Lint Rules

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Custom Lint Rules: зачем?

находить ошибки

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Custom Lint Rules: зачем?

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Custom Lint Rules: зачем?

находить ошибки
контролировать соблюдение соглашений

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Custom Lint Rules: зачем?

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Custom Lint Rules: зачем?

находить ошибки
контролировать соблюдение соглашений
избежать рутинных и повторяющихся действий

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Custom Lint Rules: зачем?

находить ошибки
контролировать соблюдение соглашений
избежать рутинных и повторяющихся действий
рефакторинг

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Custom Lint Rules

Добавить модуль

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// custom-lint-rules/build.gradle

apply plugin: 'kotlin'��dependencies {� compileOnly "com.android.tools.lint:lint-api:$lintVersion"� testCompile "com.android.tools.lint:lint-tests:$lintVersion"�}��jar {� manifest {� attributes("Lint-Registry-v2": "ru.tinkoff.CustomIssueRegistry")� }�}

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// custom-lint-rules/build.gradle

apply plugin: 'kotlin'��dependencies {� compileOnly "com.android.tools.lint:lint-api:$lintVersion"� testCompile "com.android.tools.lint:lint-tests:$lintVersion"�}��jar {� manifest {� attributes("Lint-Registry-v2": "ru.tinkoff.CustomIssueRegistry")� }�}

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lintVersion = androidGradlePluginVersion + 23.0.0

// например

androidGradlePluginVersion = "3.5.0"

lintVersion = "26.5.0"

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// custom-lint-rules/build.gradle

apply plugin: 'kotlin'��dependencies {� compileOnly "com.android.tools.lint:lint-api:$lintVersion"� testCompile "com.android.tools.lint:lint-tests:$lintVersion"�}��jar {� manifest {� attributes("Lint-Registry-v2": "ru.tinkoff.CustomIssueRegistry")� }�}

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Custom Lint Rules

Добавить модуль
Реализовать IssueRegistry

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class CustomIssueRegistry : IssueRegistry() {

override val api = CURRENT_API

override val issues: List<Issue> = listOf()

}

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class CustomIssueRegistry : IssueRegistry() {

override val api = CURRENT_API

override val issues: List<Issue> = listOf()

}

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import com.android.tools.lint.detector.api.CURRENT_API

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class CustomIssueRegistry : IssueRegistry() {

override val api = CURRENT_API

override val issues: List<Issue> = listOf()

}

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Custom Lint Rules

Добавить модуль
Реализовать IssueRegistry
Подключить модуль к проекту

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// app/build.gradle

dependencies {

lintChecks project(':custom-lint-rules')

}

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// some-kotlin-module/build.gradle

apply plugin: 'kotlin'

apply plugin: 'com.android.lint'

dependencies {

lintChecks project(':custom-lint-rules');

}

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Custom Lint Rules

Добавить модуль
Реализовать IssueRegistry
Подключить модуль к проекту
Реализовать Detector

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Пример

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@Override

protected void onActivityResult(int requestCode, int resultCode, Intent data) {

super.onActivityResult(requestCode, resultCode, data);

if (requestCode == CropImage.CROP_IMAGE_ACTIVITY_REQUEST_CODE) {

CropImage.ActivityResult result = CropImage.getActivityResult(data);

if (requestCode == Activity.RESULT_OK) {

Uri resultUri = result.getUri();

try {

Bitmap bitmap = getBitmap(getContentResolver(), resultUri);

profile_image.setImageBitmap(bitmap);

} catch (IOException e) {

e.printStackTrace();

}

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@Override

protected void onActivityResult(int requestCode, int resultCode, Intent data) {

super.onActivityResult(requestCode, resultCode, data);

if (requestCode == CropImage.CROP_IMAGE_ACTIVITY_REQUEST_CODE) {

CropImage.ActivityResult result = CropImage.getActivityResult(data);

if (requestCode == Activity.RESULT_OK) {

Uri resultUri = result.getUri();

try {

Bitmap bitmap = getBitmap(getContentResolver(), resultUri);

profile_image.setImageBitmap(bitmap);

} catch (IOException e) {

e.printStackTrace();

}

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Интерфейсы

XmlScanner
SourceCodeScanner
ClassScanner
GradleScanner
BinaryResourceScanner
ResourceFolderScanner, OtherFileScanner, ...

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SourceCodeScanner

вызовы методов с именем methodName
обращение к символам с именем symbolName
наследование от класса ClassName
использование аннотаций AnnotationName
любые другие конструкции

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UAST

Unified Abstract Syntax Tree
универсальный анализ Java и Kotlin

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// MyClass.java

public class MyClass {

String hello = "Hello!";

void bar() { }

}

// MyClass.kt

class MyClass {

val hello = "Hello!"

fun bar() { }

}

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// MyClass.java

public class MyClass {

String hello = "Hello!";

void bar() { }

}

// MyClass.kt

class MyClass {

val hello = "Hello!"

fun bar() { }

}

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UFile

UClass

(name = MyClass)

UField

(name = hello)

UMethod

(name = bar)

UBlockExpression

ULiteralExpression

(value = "Hello!")

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Алгоритм

Найти использование констант RESULT_OK, RESULT_CANCELLED
Проверить второй операнд ==
Если это requestCode, то сообщить об ошибке

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class ActivityResultDetector: Detector(), SourceCodeScanner {

companion object {

val ISSUE = Issue.create(...)

}

override fun getApplicableReferenceNames(): List<String>?

override fun visitReference(

context: JavaContext,

reference: UReferenceExpression,

referenced: PsiElement)

}

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class ActivityResultDetector: Detector(), SourceCodeScanner {

companion object {

val ISSUE = Issue.create(...)

}

override fun getApplicableReferenceNames(): List<String>?

override fun visitReference(

context: JavaContext,

reference: UReferenceExpression,

referenced: PsiElement)

}

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val ISSUE = Issue.create(

id = "ActivityResultDetector",

briefDescription = "Comparing result code to request code",

explanation = "<...>",

category = Category.CORRECTNESS,

priority = 5,

severity = Severity.ERROR,

implementation = Implementation(

ActivityResultDetector::class.java,

Scope.JAVA_FILE_SCOPE)

)

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val ISSUE = Issue.create(

id = "ActivityResultDetector",

briefDescription = "Comparing result code to request code",

explanation = "<...>",

category = Category.CORRECTNESS,

priority = 5,

severity = Severity.ERROR,

implementation = Implementation(

ActivityResultDetector::class.java,

Scope.JAVA_FILE_SCOPE)

)

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val ISSUE = Issue.create(

id = "ActivityResultDetector",

briefDescription = "Comparing result code to request code",

explanation = "<...>",

category = Category.CORRECTNESS,

priority = 5,

severity = Severity.ERROR,

implementation = Implementation(

ActivityResultDetector::class.java,

Scope.JAVA_FILE_SCOPE)

)

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val ISSUE = Issue.create(

id = "ActivityResultDetector",

briefDescription = "Comparing result code to request code",

explanation = "<...>",

category = Category.CORRECTNESS,

priority = 5,

severity = Severity.ERROR,

implementation = Implementation(

ActivityResultDetector::class.java,

Scope.JAVA_FILE_SCOPE)

)

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val ISSUE = Issue.create(

id = "ActivityResultDetector",

briefDescription = "Comparing result code to request code",

explanation = "<...>",

category = Category.CORRECTNESS,

priority = 5,

severity = Severity.ERROR,

implementation = Implementation(

ActivityResultDetector::class.java,

Scope.JAVA_FILE_SCOPE)

)

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enum class Severity {

FATAL("Fatal"),

ERROR("Error"),

WARNING("Warning"),

INFORMATIONAL("Information"),

IGNORE("Ignore")

}

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val ISSUE = Issue.create(

id = "ActivityResultDetector",

briefDescription = "Comparing result code to request code",

explanation = "<...>",

category = Category.CORRECTNESS,

priority = 5,

severity = Severity.ERROR,

implementation = Implementation(

ActivityResultDetector::class.java,

Scope.JAVA_FILE_SCOPE)

)

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enum class Scope {

RESOURCE_FILE,

JAVA_FILE,

CLASS_FILE,

MANIFEST,

PROGUARD_FILE,

GRADLE_FILE,

...

}

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class ActivityResultDetector : Detector(), SourceCodeScanner {

companion object {

val ISSUE = Issue.create(...)

}

override fun getApplicableReferenceNames(): List<String>?

override fun visitReference(

context: JavaContext,

reference: UReferenceExpression,

referenced: PsiElement)

}

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class ActivityResultDetector : Detector(), SourceCodeScanner {

companion object {

val ISSUE = Issue.create(...)

}

override fun getApplicableReferenceNames(): List<String>?

override fun visitReference(

context: JavaContext,

reference: UReferenceExpression,

referenced: PsiElement)

}

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override fun getApplicableReferenceNames(): List<String>? {

return listOf("RESULT_OK", "RESULT_CANCELED")

}

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override fun visitReference(

context: JavaContext,

reference: UReferenceExpression,

referenced: PsiElement) {

// TODO

}

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override fun visitReference(

context: JavaContext,

reference: UReferenceExpression,

referenced: PsiElement) {

// TODO

}

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override fun visitReference(

context: JavaContext,

reference: UReferenceExpression,

referenced: PsiElement) {

// TODO

}

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@Override

void onActivityResult(int requestCode, int resultCode, Intent data) {

// ...

if (requestCode == Activity.RESULT_OK) {

Uri resultUri = result.getUri();

// ...

}

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reference: UReferenceExpression

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override fun visitReference(

context: JavaContext,

reference: UReferenceExpression,

referenced: PsiElement) {

// TODO

}

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public class Activity extends ContextThemeWrapper {

/** Standard activity result: operation succeeded. */

public static final int RESULT_OK = -1;

}

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referenced: PsiElement

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PSI

Program Structure Interface
используются для представления внутренней структуры исходного кода

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@Override

void onActivityResult(int requestCode, int resultCode, Intent data) {

// ...

if (requestCode == Activity.RESULT_OK) {

Uri resultUri = result.getUri();

// ...

}

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UBinaryExpression

UQualifiedReferenceExpression

UReferenceExpression

(requestCode)

UReferenceExpression (Activity)

UReferenceExpression

(RESULT_OK)

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@Override

void onActivityResult(int requestCode, int resultCode, Intent data) {

// ...

if (requestCode == Activity.RESULT_OK) {

Uri resultUri = result.getUri();

// ...

}

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reference: UReferenceExpression

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@Override

void onActivityResult(int requestCode, int resultCode, Intent data) {

// ...

if (requestCode == Activity.RESULT_OK) {

Uri resultUri = result.getUri();

// ...

}

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UQualifiedReferenceExpression

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@Override

void onActivityResult(int requestCode, int resultCode, Intent data) {

// ...

if (requestCode == Activity.RESULT_OK) {

Uri resultUri = result.getUri();

// ...

}

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UBinaryExpression

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val comparison: UBinaryExpression =

reference.getParentOfType(UBinaryExpression::class.java)

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@Override

void onActivityResult(int requestCode, int resultCode, Intent data) {

// ...

if (requestCode == Activity.RESULT_OK) {

Uri resultUri = result.getUri();

// ...

}

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leftOperand: UExpression

rightOperand: UExpression

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val operand =

comparison.leftOperand as? UReferenceExpression

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@Override

void onActivityResult(int requestCode, int resultCode, Intent data) {

// ...

if (requestCode == Activity.RESULT_OK) {

Uri resultUri = result.getUri();

// ...

}

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method: UMethod

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@Override

void onActivityResult(int requestCode, int resultCode, Intent data) {

// ...

if (requestCode == Activity.RESULT_OK) {

Uri resultUri = result.getUri();

// ...

}

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method.parameterList.parameters[0]

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val method: UMethod? =

reference.getParentOfType(UMethod::class.java)

val paramRequestCode = method.parameterList.parameters[0]

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if (operand.resolve() == paramRequestCode) {

context.report(

issue = ActivityResultDetector.ISSUE,

location = context.getLocation(comparison),

message = "Error!"

)

}

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if (operand.resolve() == paramRequestCode) {

context.report(

issue = ActivityResultDetector.ISSUE,

location = context.getLocation(comparison),

message = "Error!"

)

}

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@Override

void onActivityResult(int requestCode, int resultCode, Intent data) {

if (requestCode == Activity.RESULT_OK) {

Uri uri = data.getData();

// ...

}

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operand: UReferenceExpression

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@Override

void onActivityResult(int requestCode, int resultCode, Intent data) {

if (requestCode == Activity.RESULT_OK) {

Uri uri = data.getData();

// ...

}

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resolve()

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if (operand.resolve() == paramRequestCode) {

context.report(

issue = ActivityResultDetector.ISSUE,

location = context.getLocation(comparison),

message = "Error!"

)

}

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if (operand.resolve() == paramRequestCode) {

context.report(

issue = ActivityResultDetector.ISSUE,

location = context.getLocation(comparison),

message = "Error!"

)

}

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class CustomIssueRegistry : IssueRegistry() {

override val api = CURRENT_API

override val issues: List<Issue> = listOf(

ActivityResultDetector.ISSUE

)

}

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class CustomIssueRegistry : IssueRegistry() {

override val api = CURRENT_API

override val issues: List<Issue> = listOf(

ActivityResultDetector.ISSUE

)

}

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HTML

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IDE

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IDE

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Проблема

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@Override

void onActivityResult(int requestCode, int resultCode, Intent data) {

// ...

if (Activity.RESULT_OK == requestCode) {

Uri resultUri = result.getUri();

// ...

}

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@Override

void onActivityResult(int requestCode, int resultCode, Intent data) {

// ...

if (Activity.RESULT_OK == requestCode) {

Uri resultUri = result.getUri();

// ...

}

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val operand =

comparison.leftOperand as? UReferenceExpression

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val operand: UReferenceExpression? =

comparison.leftOperand as? UReferenceExpression

getAnotherOperand(comparison, reference)

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private fun getAnotherOperand(

comparison: UBinaryExpression,

referenceToField: UReferenceExpression

): UReferenceExpression? {

return if (comparison.leftOperand == referenceToField) {

comparison.rightOperand

} else {

comparison.leftOperand

} as? UReferenceExpression

}

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IDE

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Проблема №2

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val method = reference.getParentOfType(UMethod::class.java)

if (!isOnActivityResult(context, method)) {

return

}

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fun isOnActivityResult(

context: JavaContext,

method: UMethod

): Boolean {

return context.evaluator.methodMatches(

method,

"android.app.Activity",

false,

"int", "int", "android.content.Intent"

)

}

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Utils

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SdkConstants

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Utils

LintUtils
UastLintUtils
extenstions

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Отладка

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fun UElement.asRecursiveLogString(): String

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UMethod (name = onActivityResult)

UAnnotation (fqName = java.lang.Override)

UParameter (name = requestCode)

UParameter (name = resultCode)

UParameter (name = data)

UBlockExpression

UIfExpression

UBinaryExpression (operator = ===)

USimpleNameReferenceExpression (id = requestCode)

UQualifiedReferenceExpression

USimpleNameReferenceExpression (id = Activity)

USimpleNameReferenceExpression (id = RESULT_OK)

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PsiViewer plugin

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# ~/.AndroidStudio3.x/config/idea.properties

idea.is.internal=true

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View PSI structure

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Отладка

-Dorg.gradle.debug=true

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$ ./gradle lintDebug \

-Dorg.gradle.debug=true \

--no-daemon

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Отладка

-Dorg.gradle.debug=true
Run → Attach to Process

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Отладка

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LintFix

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val paramResultCode = method.parameterList.parameters[1]

val fix = LintFix.create()

.replace()

.text(paramRequestCode.name)

.with(paramResultCode.name)

.build()

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val paramResultCode = method.parameterList.parameters[1]

val fix = LintFix.create()

.replace()

.text(paramRequestCode.name)

.with(paramResultCode.name)

.build()

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context.report(

issue = ActivityResultDetector.ISSUE,

location = context.getLocation(comparison),

message = "Error!",

quickfixData = fix

)

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LintFix

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LintFix

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Тесты

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val testData = """

import android.app.Activity;

import android.content.Intent;

class MyActivity extends Activity {

@Override

public void onActivityResult(<...>) {

if (requestCode == Activity.RESULT_OK) {

}

""".trimIndent()

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val expectedText = """

|src/MyActivity.java:7: Error: Error!

| if (requestCode == Activity.RESULT_OK) {

| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

|1 errors, 0 warnings

""".trimMargin()

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@Test

fun basicScenario() {

val testData = "<...>"

val expectedText = "<...>"

TestLintTask.lint()

.files(java(testData))

.issues(ActivityResultDetector.ISSUE)

.run()

.expect(expectedText)

}

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val expectedFixDiffs = """

|Fix for src/MyActivity.java line 7: Replace:

|@@ -7 +7

|- if (requestCode == Activity.RESULT_OK) {

|+ if (resultCode == Activity.RESULT_OK) {

""".trimMargin()

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@Test

fun quickfix() {

val testData = "<...>"

val expectedFixDiffs = "<...>"

TestLintTask.lint()

.files(java(testData))

.issues(ActivityResultDetector.ISSUE)

.run()

.expectErrorCount(1)

.expectFixDiffs(expectedFixDiffs)

}

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Решение проблем

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java.lang.AssertionError: This test requires an Android SDK: No SDK configured.

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Запуск тестов

Run → Edit configurations

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class MyClass {

@MyAnnotation

fun foobar() {

}

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UFile (package = )

UClass (name = MyClass)

UAnnotationMethod (name = foobar)

UBlockExpression

UAnnotationMethod (name = MyClass)

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UFile (package = )

UClass (name = MyClass)

UAnnotationMethod (name = foobar)

UBlockExpression

UAnnotationMethod (name = MyClass)

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Решения

скопировать код в тест (stubs)

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val myAnnotation = "annotation class MyAnnotation"

TestLintTask.lint()

.files(kotlin(testData), kotlin(myAnnotation))

.issues(ISSUE)

.run()

.expect(expectedText)

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val myAnnotation = "annotation class MyAnnotation"

TestLintTask.lint()

.files(kotlin(testData), kotlin(myAnnotation))

.issues(ISSUE)

.run()

.expect(expectedText)

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UFile (package = )

UClass (name = MyClass)

UAnnotationMethod (name = foobar)

UAnnotation (fqName = MyAnnotation)

UBlockExpression

UAnnotationMethod (name = MyClass)

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UFile (package = )

UClass (name = MyClass)

UAnnotationMethod (name = foobar)

UAnnotation (fqName = MyAnnotation)

UBlockExpression

UAnnotationMethod (name = MyClass)

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Решения

скопировать код в тест (stubs)
подключить JAR

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val targetPath = "libs/my-lib.jar"

val producer = object : TestFile.BytecodeProducer() {

override fun produce() = // read bytes from resources

}

val myLib = bytecode(targetPath, producer)

TestLintTask.lint()

.files(kotlin(file), classpath(targetPath), myLib)

.issues(ISSUE)

.run()

.expect(expectedText)

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Недостатки

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Недостатки

мало документации
высокий порог входа
рефакторинг может принести проблем
требуется поддержка
баги

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Заключение

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Заключение

чем раньше выявим баг - тем раньше его исправим
то, что можно автоматизировать - нужно автоматизировать
lint - не панацея

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Полезные материалы

Kotlin Static Analysis with Android Lint
Safe(r) Kotlin Code - Static Analysis Tools for Kotlin
Coding in Style: Static Analysis with Custom Lint Rules
lint-dev - Google Groups

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Android Lint performance probe

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Вопросы?

t.me/italankin

github.com/italankin

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