Recurse preview annotations to check for inherited Previews

Resolves #377
slackhq · Oct 1, 2024 · 7d66761 · 7d66761
1 parent e2f7ef4
commit 7d66761
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diff --git a/compose-lint-checks/src/main/java/slack/lint/compose/util/Previews.kt b/compose-lint-checks/src/main/java/slack/lint/compose/util/Previews.kt
@@ -5,6 +5,7 @@ package slack.lint.compose.util
 
 import org.jetbrains.uast.UAnnotated
 import org.jetbrains.uast.UParameter
+import org.jetbrains.uast.toUElementOfType
 
 private const val COMPOSE_PREVIEW = "androidx.compose.ui.tooling.preview.Preview"
 private const val COMPOSE_DESKTOP_PREVIEW = "androidx.compose.desktop.ui.tooling.preview.Preview"
@@ -18,15 +19,22 @@ val TEST_ANNOTATIONS =
   )
 
 val UAnnotated.isPreview: Boolean
-  get() =
-    uAnnotations.any {
-      it.resolve()?.let { cls ->
-        cls.qualifiedName in PREVIEW_ANNOTATIONS ||
-          // Is the annotation itself a preview-annotated annotation?
-          cls.hasAnnotation(COMPOSE_PREVIEW) ||
-          cls.hasAnnotation(COMPOSE_DESKTOP_PREVIEW)
-      } ?: false
-    }
+  get() = checkIsPreview(0, maxDepth = 4)
+
+/**
+ * Previews can go multiple layers so we can recurse up to check. In [UAnnotated.isPreview] we cap
+ * it at 4 to be reasonable.
+ */
+private fun UAnnotated.checkIsPreview(depth: Int, maxDepth: Int): Boolean {
+  if (depth >= maxDepth) return false
+  return uAnnotations.any {
+    it.resolve()?.let { cls ->
+      cls.qualifiedName in PREVIEW_ANNOTATIONS ||
+        // Is the annotation itself a preview-annotated annotation?
+        cls.toUElementOfType<UAnnotated>()?.checkIsPreview(depth + 1, maxDepth) == true
+    } ?: false
+  }
+}
 
 val UAnnotated.isVisibleForTesting: Boolean
   get() =

diff --git a/compose-lint-checks/src/test/java/slack/lint/compose/ModifierMissingDetectorTest.kt b/compose-lint-checks/src/test/java/slack/lint/compose/ModifierMissingDetectorTest.kt
@@ -372,6 +372,36 @@ class ModifierMissingDetectorTest : BaseComposeLintTest() {
     lint().files(*commonStubs, kotlin(code)).run().expectClean()
   }
 
+  // https://github.com/slackhq/compose-lints/issues/377
+  @Test
+  fun `deeply nested previews can still be detected and allowed`() {
+    @Language("kotlin")
+    val code =
+      """
+          import androidx.compose.runtime.Composable
+          import androidx.compose.ui.tooling.preview.Preview
+          import androidx.compose.ui.Modifier
+
+          @Preview
+          annotation class DeviceWidthPreviews
+
+          @DeviceWidthPreviews
+          annotation class ThemePreviews
+
+          @ThemePreviews
+          annotation class ComponentPreviews
+
+          @ComponentPreviews
+          @Composable
+          fun Something() {
+            Text("Hi")
+          }
+      """
+        .trimIndent()
+
+    lint().files(*commonStubs, kotlin(code)).run().expectClean()
+  }
+
   @Test
   fun `non content emitting root composables are ignored`() {
     @Language("kotlin")