fix(databinding): reject unsupported two-way adapters

Treat two-way BindingAdapter expressions as unsupported until an inverse adapter contract and reverse listener can be generated.

Tested: ./gradlew test :demo:assembleDebug --warning-mode all --no-daemon

Author: donglua

README.md

@@ -236,6 +236,8 @@ object LayoutX2CConfig {
 
 例如 `app:stateColorRes="@{R.color.sample_state}"` 和 `app:stateSizeDp="@{3F}"`
 会生成类似 `SampleBindingAdapters.setViewState(view, R.color.sample_state, 3f)`。
+当前白名单只描述正向 `BindingAdapter`。`@={}` 双向表达式还需要 inverse adapter
+和反向监听器契约，因此会标记为 unsupported 并继续 fallback。
 `attrs` 推荐写 XML 完整属性名；自定义 `app:` 属性也兼容无前缀写法，
 例如 `"stateColorRes"` 会按 `app:stateColorRes` 匹配。
 

compiler-core/src/main/kotlin/com/github/donglua/layoutx2c/analyzer/LayoutAnalyzerV2.kt

@@ -185,9 +185,8 @@ class LayoutAnalyzerV2(
                 isXmlnsAttribute(attrName) -> { /* 忽略 */ }
                 isToolsAttribute(attrName) -> supported.add(attrName)
                 (isOneWay || isTwoWay) && isDeclaredBindingAdapterAttribute(attrName) -> {
-                    if (isSupportedBindingAdapterExpression(attrValue)) {
+                    if (!isTwoWay && isSupportedBindingAdapterExpression(attrValue)) {
                         dataBinding.add(attrName)
-                        if (isTwoWay) twoWayBinding.add(attrName)
                     } else {
                         unsupported.add(attrName)
                     }

compiler-core/src/test/kotlin/com/github/donglua/layoutx2c/codegen/TwoWayBindingAdapterBoundaryTest.kt

@@ -0,0 +1,53 @@
+package com.github.donglua.layoutx2c.codegen
+
+import com.github.donglua.layoutx2c.analyzer.LayoutAnalyzerV2
+import com.github.donglua.layoutx2c.parser.XmlLayoutParser
+import com.google.common.truth.Truth.assertThat
+import org.junit.Test
+
+class TwoWayBindingAdapterBoundaryTest {
+
+    @Test
+    fun `two-way binding adapter is unsupported without an inverse adapter contract`() {
+        val bindingAdapters = listOf(
+            BindingAdapterDescriptor(
+                attrs = listOf("app:stateColorRes"),
+                methodClassName = "com.example.databinding.SampleBindingAdapters",
+                methodName = "setStateColor"
+            )
+        )
+        val tree = XmlLayoutParser().parse(
+            """
+                <layout xmlns:android="http://schemas.android.com/apk/res/android"
+                    xmlns:app="http://schemas.android.com/apk/res-auto">
+                    <data>
+                        <variable name="vm" type="com.example.StateViewModel" />
+                    </data>
+                    <View
+                        android:id="@+id/state_indicator"
+                        android:layout_width="6dp"
+                        android:layout_height="6dp"
+                        app:stateColorRes="@={vm.colorRes}" />
+                </layout>
+            """.trimIndent(),
+            "item_two_way_binding_adapter"
+        )
+        val analyzed = LayoutAnalyzerV2(bindingAdapters = bindingAdapters).analyze(tree.root)
+
+        val generated = BindingFacadeGeneratorV2(
+            packageName = "com.example.generated",
+            rPackageName = "com.example",
+            bindingAdapters = bindingAdapters
+        ).generate(
+            analyzedRoot = analyzed,
+            layoutName = "item_two_way_binding_adapter",
+            layoutResId = "R.layout.item_two_way_binding_adapter",
+            useFastPath = true,
+            dataBindingVariables = tree.rootMetadata.dataBindingVariables
+        ).toString()
+
+        assertThat(analyzed.unsupportedAttributes).contains("app:stateColorRes")
+        assertThat(analyzed.twoWayBindingAttributes).doesNotContain("app:stateColorRes")
+        assertThat(generated).doesNotContain("SampleBindingAdapters.setStateColor")
+    }
+}

runtime/src/main/java/com/github/donglua/layoutx2c/runtime/annotation/FastBindingAdapter.kt

@@ -3,7 +3,8 @@ package com.github.donglua.layoutx2c.runtime.annotation
 import kotlin.reflect.KClass
 
 /**
- * Declares one DataBinding BindingAdapter method that LayoutX2C may call directly.
+ * Declares one one-way DataBinding BindingAdapter method that LayoutX2C may call directly.
+ * Two-way expressions require an inverse adapter contract and are not generated.
  */
 @PublicApi
 @MustBeDocumented

runtime/src/main/java/com/github/donglua/layoutx2c/runtime/annotation/FastBindingAdapters.kt

@@ -1,7 +1,7 @@
 package com.github.donglua.layoutx2c.runtime.annotation
 
 /**
- * Declares DataBinding BindingAdapter methods that LayoutX2C may call directly.
+ * Declares one-way DataBinding BindingAdapter methods that LayoutX2C may call directly.
  */
 @PublicApi
 @MustBeDocumented