refactor: improve safety and logging in TestoIconProvider icon resolution

Author: xepozz

src/main/kotlin/com/github/xepozz/testo/ui/TestoIconProvider.kt

@@ -4,6 +4,9 @@ import com.github.xepozz.testo.TestoIcons
 import com.github.xepozz.testo.TestoUtil
 import com.github.xepozz.testo.isTestoFile
 import com.intellij.ide.IconProvider
+import com.intellij.openapi.diagnostic.logger
+import com.intellij.openapi.progress.ProcessCanceledException
+import com.intellij.openapi.roots.ProjectFileIndex
 import com.intellij.openapi.util.Iconable
 import com.intellij.psi.PsiElement
 import com.intellij.psi.search.GlobalSearchScopesCore
@@ -13,23 +16,42 @@ import com.jetbrains.php.lang.psi.elements.PhpClass
 import javax.swing.Icon
 
 class TestoIconProvider : IconProvider() {
+    private val log = logger<TestoIconProvider>()
+
     override fun getIcon(element: PsiElement, @Iconable.IconFlags flags: Int): Icon? {
-        val phpFile = element as? PhpFile ?: return null
-        if (!TestoUtil.isEnabled(element.project)) return null
+        return try {
+            val phpFile = element as? PhpFile ?: return null
+            val project = element.project
+            if (!TestoUtil.isEnabled(project)) return null
 
-        if (!phpFile.isTestoFile()) return null
-        if (!GlobalSearchScopesCore.projectTestScope(element.project).contains(phpFile.virtualFile)) {
-            return null
-        }
+            val virtualFile = phpFile.virtualFile ?: return null
+            if (!virtualFile.isValid) return null
+
+            val fileIndex = ProjectFileIndex.getInstance(project)
+            // Quick exit: file is not in project content, is excluded, or is ignored by the IDE.
+            if (!fileIndex.isInContent(virtualFile)) return null
+            if (fileIndex.isExcluded(virtualFile)) return null
+            if (fileIndex.isUnderIgnored(virtualFile)) return null
+
+            if (!phpFile.isTestoFile()) return null
+            if (!GlobalSearchScopesCore.projectTestScope(project).contains(virtualFile)) {
+                return null
+            }
 
-        val phpClasses = PsiTreeUtil.findChildrenOfType(phpFile, PhpClass::class.java)
+            val phpClasses = PsiTreeUtil.findChildrenOfType(phpFile, PhpClass::class.java)
 
-        return when {
-            phpClasses.isEmpty() -> TestoIcons.Layered.FUNCTION
-            phpClasses.size > 1 -> TestoIcons.Layered.FILE
-            phpClasses.first().modifier.isAbstract -> TestoIcons.Layered.Class.CLASS_ABSTRACT
-            phpClasses.first().modifier.isFinal -> TestoIcons.Layered.Class.CLASS_FINAL
-            else -> TestoIcons.Layered.Class.CLASS
+            when {
+                phpClasses.isEmpty() -> TestoIcons.Layered.FUNCTION
+                phpClasses.size > 1 -> TestoIcons.Layered.FILE
+                phpClasses.first().modifier.isAbstract -> TestoIcons.Layered.Class.CLASS_ABSTRACT
+                phpClasses.first().modifier.isFinal -> TestoIcons.Layered.Class.CLASS_FINAL
+                else -> TestoIcons.Layered.Class.CLASS
+            }
+        } catch (e: ProcessCanceledException) {
+            throw e
+        } catch (e: Throwable) {
+            log.warn("Failed to compute Testo icon for element: ${element.javaClass.name}", e)
+            null
         }
     }
 }