IDEA-345136 Improve error handling

GitOrigin-RevId: 644d1ad6be0cc60ef87dcc3cb0f262518761c157

platform/lang-impl/src/com/intellij/ide/fileTemplates/impl/DefaultTemplate.kt

@@ -101,8 +101,9 @@ class DefaultTemplate(val name: String,
 
     if (text == null) {
       logger<DefaultTemplate>().error("Cannot find file by path: $fullPath")
+      return "Unexpected error occurred"
     }
-    return text ?: ""
+    return text
   }
 
   // the only external usage - https://github.com/wrdv/testme-idea/blob/8e314aea969619f43f0c6bb17f53f1d95b1072be/src/main/java/com/weirddev/testme/intellij/ui/template/FTManager.java#L200

platform/lang-impl/src/com/intellij/ide/fileTemplates/impl/FileTemplatesLoader.kt

@@ -342,8 +342,9 @@ private fun getLocalizedContent(path: String, pathResolver: Function<String, Str
   val result = pathResolver.apply(fullPath.invariantSeparatorsPathString)
   if (result == null) {
     logger<FileTemplatesLoader>().error("Cannot find file by path: $path")
+    return "Unexpected error occurred"
   }
-  return result ?: ""
+  return result
 }
 
 private fun loadFileContent(root: Path, filePath: String): String? {