Better lint integration. (#1068)

Author: vanniktech

build.gradle

@@ -1,14 +1,15 @@
-apply from: 'constants.gradle'
-
 buildscript {
+    apply from: 'constants.gradle'
+
     repositories {
         google()
         jcenter()
         mavenLocal()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.0.0'
+        classpath 'com.android.tools.build:gradle:3.0.1'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
         classpath 'com.google.gms:google-services:3.1.1'
         classpath 'com.jfrog.bintray.gradle:gradle-bintray-plugin:1.7.3'
     }

constants.gradle

@@ -11,4 +11,5 @@ project.ext {
     firebaseVersion = '11.8.0'
     supportLibraryVersion = '27.0.2'
     architectureVersion = '1.0.0'
+    kotlinVersion = '1.2.10'
 }

lint/build.gradle

@@ -1,14 +1,12 @@
-apply plugin: 'java-library'
-
-configurations {
-    lintChecks
-}
+apply plugin: 'kotlin'
 
 dependencies {
     compileOnly 'com.android.tools.lint:lint-api:26.0.1'
-    compileOnly 'com.android.tools.lint:lint-checks:26.0.1'
-}
+    compileOnly "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlinVersion"
 
+    testImplementation 'com.android.tools.lint:lint-api:26.0.1'
+    testImplementation 'com.android.tools.lint:lint-tests:26.0.1'
+}
 
 jar {
     manifest {

lint/src/main/java/com/firebaseui/lint/LintIssueRegistry.java

@@ -0,0 +1,10 @@
+package com.firebaseui.lint
+
+import com.android.tools.lint.client.api.IssueRegistry
+
+/**
+ * Registry for custom FirebaseUI lint checks.
+ */
+class LintIssueRegistry : IssueRegistry() {
+    override fun getIssues() = listOf(NonGlobalIdDetector.NON_GLOBAL_ID)
+}

lint/src/main/java/com/firebaseui/lint/LintIssueRegistry.kt

@@ -0,0 +1,52 @@
+package com.firebaseui.lint
+
+import com.android.tools.lint.detector.api.Category
+import com.android.tools.lint.detector.api.Detector
+import com.android.tools.lint.detector.api.Implementation
+import com.android.tools.lint.detector.api.Issue
+import com.android.tools.lint.detector.api.LayoutDetector
+import com.android.tools.lint.detector.api.Scope
+import com.android.tools.lint.detector.api.Severity
+import com.android.tools.lint.detector.api.XmlContext
+import org.w3c.dom.Element
+
+/**
+ * Lint detector to find layout attributes that reference "@id" where they should reference
+ * "@+id" instead.
+ */
+class NonGlobalIdDetector : LayoutDetector() {
+    override fun getApplicableElements(): List<String> = Detector.XmlScanner.ALL
+
+    override fun visitElement(context: XmlContext, element: Element) {
+        (0 until element.attributes.length)
+                .map { element.attributes.item(it) }
+                .filter { it.nodeValue.contains(NON_GLOBAL_ID_PREFIX) }
+                .forEach {
+                    val quickFix = fix()
+                            .replace()
+                            .name("Fix id")
+                            .text(it.nodeValue)
+                            .with(it.nodeValue.replace(NON_GLOBAL_ID_PREFIX, GLOBAL_ID_PREFIX))
+                            .build()
+
+                    context.report(NON_GLOBAL_ID, it, context.getLocation(it), REPORT_MESSAGE, quickFix)
+                }
+    }
+
+    companion object {
+        private const val NON_GLOBAL_ID_PREFIX = "@id"
+        private const val GLOBAL_ID_PREFIX = "@+id"
+
+        private const val REPORT_MESSAGE = "Use of non-global @id in layout file, consider using @+id instead for compatibility with aapt1."
+
+        val NON_GLOBAL_ID = Issue.create(
+                "NonGlobalIdInLayout",
+                "Usage of non-global @id in layout file.",
+                "To maintain compatibility with aapt1, it is safer to always use @+id in layout files.",
+                Category.CORRECTNESS,
+                8,
+                Severity.ERROR,
+                Implementation(NonGlobalIdDetector::class.java, Scope.ALL_RESOURCES_SCOPE)
+        )
+    }
+}

lint/src/main/java/com/firebaseui/lint/NonGlobalIdDetector.java

@@ -0,0 +1,43 @@
+package com.firebaseui.lint
+
+import com.android.tools.lint.checks.infrastructure.TestFiles.xml
+import com.android.tools.lint.checks.infrastructure.TestLintTask.lint
+import com.firebaseui.lint.NonGlobalIdDetector.Companion.NON_GLOBAL_ID
+import org.junit.Test
+
+class NonGlobalIdDetectorTest {
+    @Test
+    fun validId() {
+        lint()
+                .files(xml("res/layout/layout.xml", """
+                        |<RelativeLayout
+                        |    xmlns:android="http://schemas.android.com/apk/res/android"
+                        |    android:id="@+id/valid"/>""".trimMargin()))
+                .issues(NON_GLOBAL_ID)
+                .run()
+                .expectClean()
+    }
+
+    @Test
+    fun invalidId() {
+        lint()
+                .files(xml("res/layout/layout.xml", """
+                        |<ScrollView
+                        |    xmlns:android="http://schemas.android.com/apk/res/android"
+                        |    android:id="@id/invalid"/>""".trimMargin()))
+                .issues(NON_GLOBAL_ID)
+                .run()
+                .expect("""
+                        |res/layout/layout.xml:3: Error: Use of non-global @id in layout file, consider using @+id instead for compatibility with aapt1. [NonGlobalIdInLayout]
+                        |    android:id="@id/invalid"/>
+                        |    ~~~~~~~~~~~~~~~~~~~~~~~~
+                        |1 errors, 0 warnings""".trimMargin())
+                .expectFixDiffs("""
+                        |Fix for res/layout/layout.xml line 2: Fix id:
+                        |@@ -3 +3
+                        |-     android:id="@id/invalid"/>
+                        |@@ -4 +3
+                        |+     android:id="@+id/invalid"/>
+                        |""".trimMargin())
+    }
+}