Ban usage of var in Component.

RELNOTES=n/a PiperOrigin-RevId: 560887022
google · Aug 29, 2023 · f5d686d · f5d686d
1 parent 232e524
commit f5d686d
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diff --git a/java/dagger/internal/codegen/validation/ComponentValidator.java b/java/dagger/internal/codegen/validation/ComponentValidator.java
@@ -168,6 +168,7 @@ ValidationReport validateElement() {
         // the remaining checks will likely just output unhelpful noise in such cases.
         return report.addError(invalidTypeError(), component).build();
       }
+      validateFields();
       validateUseOfCancellationPolicy();
       validateIsAbstractType();
       validateCreators();
@@ -208,6 +209,18 @@ private String invalidTypeError() {
           componentKind().annotation().simpleName());
     }
 
+    private void validateFields() {
+      component.getDeclaredMethods().stream()
+          .filter(method -> method.isKotlinPropertySetter() && method.isAbstract())
+          .forEach(
+              method ->
+                  report.addError(
+                      String.format(
+                          "Cannot use 'abstract var' property in a component declaration to get a"
+                              + " binding. Use 'val' or 'fun' instead: %s",
+                          method.getPropertyName())));
+    }
+
     private void validateCreators() {
       ImmutableSet<XTypeElement> creators =
           enclosedAnnotatedTypes(component, creatorAnnotationsFor(componentAnnotation()));

diff --git a/javatests/dagger/internal/codegen/ComponentProcessorTest.java b/javatests/dagger/internal/codegen/ComponentProcessorTest.java
@@ -2045,4 +2045,76 @@ public void injectedTypeHasGeneratedParam() {
               subject.hasWarningCount(0);
           });
   }
+
+  @Test
+  public void abstractVarFieldInComponent_failsValidation() {
+    Source component =
+        CompilerTests.kotlinSource(
+            "test.TestComponent.kt",
+            "package test",
+            "",
+            "import dagger.Component",
+            "",
+            "@Component(modules = [TestModule::class])",
+            "interface TestComponent {",
+            " var foo: String",
+            "}");
+
+    Source module =
+        CompilerTests.javaSource(
+            "test.TestModule",
+            "package test;",
+            "",
+            "import dagger.Module;",
+            "import dagger.Provides;",
+            "",
+            "@Module",
+            "abstract class TestModule {",
+            "  @Provides",
+            "  static String provideString() { return \"hello\"; }",
+            "}");
+
+    CompilerTests.daggerCompiler(component, module)
+        .withProcessingOptions(compilerMode.processorOptions())
+        .compile(
+            subject -> {
+              subject.hasErrorCount(1);
+              subject.hasErrorContaining(
+                  "Cannot use 'abstract var' property in a component declaration to get a binding."
+                      + " Use 'val' or 'fun' instead: foo");
+            });
+  }
+
+  @Test
+  public void nonAbstractVarFieldInComponent_passesValidation() {
+    Source component =
+        CompilerTests.kotlinSource(
+            "test.TestComponent.kt",
+            "package test",
+            "",
+            "import dagger.Component",
+            "",
+            "@Component(modules = [TestModule::class])",
+            "abstract class TestComponent {",
+            " var foo: String = \"hello\"",
+            "}");
+
+    Source module =
+        CompilerTests.javaSource(
+            "test.TestModule",
+            "package test;",
+            "",
+            "import dagger.Module;",
+            "import dagger.Provides;",
+            "",
+            "@Module",
+            "abstract class TestModule {",
+            "  @Provides",
+            "  static String provideString() { return \"hello\"; }",
+            "}");
+
+    CompilerTests.daggerCompiler(component, module)
+        .withProcessingOptions(compilerMode.processorOptions())
+        .compile(subject -> subject.hasErrorCount(0));
+  }
 }