Ignore lambdas that dont return Unit in ContentSlotReused

mrmans0n · Nov 19, 2024 · 5808d61 · 5808d61
1 parent fd1618d
commit 5808d61
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Showing 4 changed files with 71 additions and 1 deletion.
diff --git a/rules/common/src/main/kotlin/io/nlopez/compose/core/util/KtCallableDeclarations.kt b/rules/common/src/main/kotlin/io/nlopez/compose/core/util/KtCallableDeclarations.kt
@@ -52,5 +52,5 @@ fun KtCallableDeclaration.contentSlots(
     treatAsComposableLambdaTypes: Set<String>,
 ): Sequence<KtParameter> = valueParameters.asSequence()
     .filter { parameter ->
-        parameter.typeReference?.isComposableLambda(treatAsLambdaTypes, treatAsComposableLambdaTypes) == true
+        parameter.typeReference?.isComposableUiEmitterLambda(treatAsLambdaTypes, treatAsComposableLambdaTypes) == true
     }
diff --git a/rules/common/src/main/kotlin/io/nlopez/compose/core/util/Lambdas.kt b/rules/common/src/main/kotlin/io/nlopez/compose/core/util/Lambdas.kt
@@ -39,6 +39,37 @@ fun KtTypeReference.isComposableLambda(
     else -> false
 }
 
+fun KtTypeReference.isComposableUiEmitterLambda(
+    treatAsLambdaTypes: Set<String> = emptySet(),
+    treatAsComposableLambdaTypes: Set<String> = emptySet(),
+): Boolean = when (val element = typeElement) {
+    null -> false
+    is KtFunctionType -> isComposable && element.returnsUnit
+    is KtNullableType -> (isComposable && element.isLambda(treatAsLambdaTypes)) ||
+        // Only possibility for this to not have a @Composable annotation is for it to be a KtUserType
+        (element.innerType as? KtUserType)?.referencedName in treatAsComposableLambdaTypes
+
+    is KtUserType -> (isComposable && element.referencedName in treatAsLambdaTypes) ||
+        element.referencedName in treatAsComposableLambdaTypes
+
+    else -> false
+}
+
+val KtTypeElement.returnsUnit: Boolean
+    get() = when (this) {
+        is KtFunctionType -> returnTypeReference?.text == "Unit"
+        is KtNullableType -> innerType?.returnsUnit == true
+        else -> false
+    }
+
+val KtTypeReference.returnsUnit: Boolean
+    get() = when (val element = typeElement) {
+        null -> false
+        is KtFunctionType -> element.returnsUnit
+        is KtNullableType -> element.innerType?.returnsUnit == true
+        else -> false
+    }
+
 fun KtFile.lambdaTypes(config: ComposeKtConfig): Set<String> = buildSet {
     // Add the provided types
     addAll(config.getSet("treatAsLambda", emptySet()))

diff --git a/rules/detekt/src/test/kotlin/io/nlopez/compose/rules/detekt/ContentSlotReusedCheckTest.kt b/rules/detekt/src/test/kotlin/io/nlopez/compose/rules/detekt/ContentSlotReusedCheckTest.kt
@@ -144,4 +144,24 @@ class ContentSlotReusedCheckTest {
         val errors = rule.lint(code)
         assertThat(errors).isEmpty()
     }
+
+    @Test
+    fun `passes when content does not return Unit`() {
+        @Language("kotlin")
+        val code =
+            """
+                @Composable
+                fun A(text: String, content: @Composable () -> String) {
+                    if (x) content() else content()
+                }
+                @Composable
+                fun B(text: String, content: @Composable (() -> String)?) {
+                    if (x) content() else content()
+                }
+
+            """.trimIndent()
+
+        val errors = rule.lint(code)
+        assertThat(errors).isEmpty()
+    }
 }
diff --git a/rules/ktlint/src/test/kotlin/io/nlopez/compose/rules/ktlint/ContentSlotReusedCheckTest.kt b/rules/ktlint/src/test/kotlin/io/nlopez/compose/rules/ktlint/ContentSlotReusedCheckTest.kt
@@ -170,4 +170,23 @@ class ContentSlotReusedCheckTest {
             .withEditorConfigOverride(treatAsComposableLambda to "Potato", treatAsLambda to "Plum")
             .hasNoLintViolations()
     }
+
+    @Test
+    fun `passes when content does not return Unit`() {
+        @Language("kotlin")
+        val code =
+            """
+                @Composable
+                fun A(text: String, content: @Composable () -> String) {
+                    if (x) content() else content()
+                }
+                @Composable
+                fun B(text: String, content: @Composable (() -> String)?) {
+                    if (x) content() else content()
+                }
+
+            """.trimIndent()
+
+        ruleAssertThat(code).hasNoLintViolations()
+    }
 }