Suppress naming style inspection for composable functions (#889)

This change suppresses a diagnostic,
which complaints, when a function starts
with an upper case letter

idea-plugin/src/main/kotlin/org/jetbrains/compose/desktop/ide/preview/locationUtils.kt

@@ -16,6 +16,10 @@
 
 package org.jetbrains.compose.desktop.ide.preview
 
+import com.intellij.openapi.roots.ProjectRootModificationTracker
+import com.intellij.psi.PsiElement
+import com.intellij.psi.util.CachedValueProvider
+import com.intellij.psi.util.CachedValuesManager
 import com.intellij.psi.util.parentOfType
 import org.jetbrains.kotlin.asJava.findFacadeClass
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
@@ -28,6 +32,7 @@ import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 
 internal const val DESKTOP_PREVIEW_ANNOTATION_FQN = "androidx.compose.desktop.ui.tooling.preview.Preview"
+internal const val COMPOSABLE_FQ_NAME = "androidx.compose.runtime.Composable"
 
 /**
  * Utils based on functions from AOSP, taken from
@@ -50,6 +55,7 @@ internal fun KtNamedFunction.isValidComposePreview() =
  */
 internal fun KtNamedFunction.isValidPreviewLocation(): Boolean {
     if (valueParameters.size > 0) return false
+    if (receiverTypeReference != null) return false
 
     if (isTopLevel) return true
 
@@ -111,4 +117,19 @@ private fun KtAnnotationEntry.getQualifiedName(): String? =
 
 internal fun KtNamedFunction.composePreviewFunctionFqn() = "${getClassName()}.${name}"
 
+// based on AndroidComposePsiUtils.kt from AOSP
+internal fun PsiElement.isComposableFunction(): Boolean {
+    if (this !is KtNamedFunction) return false
 
+    return CachedValuesManager.getCachedValue(this) {
+        val hasComposableAnnotation = annotationEntries.any { it.fqNameMatches(COMPOSABLE_FQ_NAME) }
+        val containingKtFile = this.containingKtFile
+
+        CachedValueProvider.Result.create(
+            // TODO: see if we can handle alias imports without ruining performance.
+            hasComposableAnnotation,
+            containingKtFile,
+            ProjectRootModificationTracker.getInstance(project)
+        )
+    }
+}

idea-plugin/src/main/kotlin/org/jetbrains/compose/inspections/ComposeSuppressor.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.compose.inspections
+
+import com.intellij.codeInspection.InspectionSuppressor
+import com.intellij.codeInspection.SuppressQuickFix
+import com.intellij.psi.PsiElement
+import org.jetbrains.compose.desktop.ide.preview.isComposableFunction
+import org.jetbrains.kotlin.idea.KotlinLanguage
+import org.jetbrains.kotlin.lexer.KtTokens
+
+/**
+ * Suppress inspection that require composable function names to start with a lower case letter.
+ */
+class ComposeSuppressor : InspectionSuppressor {
+    override fun isSuppressedFor(element: PsiElement, toolId: String): Boolean {
+        return toolId == "FunctionName" &&
+                element.language == KotlinLanguage.INSTANCE &&
+                element.node.elementType == KtTokens.IDENTIFIER &&
+                element.parent.isComposableFunction()
+    }
+
+    override fun getSuppressActions(element: PsiElement?, toolId: String): Array<SuppressQuickFix> {
+        return SuppressQuickFix.EMPTY_ARRAY
+    }
+}
+

idea-plugin/src/main/resources/META-INF/plugin.xml

@@ -36,5 +36,7 @@
                 factoryClass="org.jetbrains.compose.desktop.ide.preview.PreviewToolWindow"
                 id="Desktop Preview" doNotActivateOnStart="true"
                 anchor="right" />
+
+        <lang.inspectionSuppressor language="kotlin" implementationClass="org.jetbrains.compose.inspections.ComposeSuppressor"/>
     </extensions>
 </idea-plugin>