Refactored the OPML load code so that the normalization step is separate from the add step.

Frameworks/Account/Account.swift

@@ -468,43 +468,25 @@ public final class Account: DisplayNameProvider, UnreadCountProvider, Container,
 		delegate.accountWillBeDeleted(self)
 	}
 
-	func loadOPMLItems(_ items: [RSOPMLItem], parentFolder: Folder?) {
+	func addOPMLItems(_ items: [RSOPMLItem]) {
-		var feedsToAdd = Set<WebFeed>()
+		for item in items {
-
-		items.forEach { (item) in
-
 			if let feedSpecifier = item.feedSpecifier {
-				let feed = newWebFeed(with: feedSpecifier)
+				addWebFeed(newWebFeed(with: feedSpecifier))
-				feedsToAdd.insert(feed)
+			} else {
-				return
+				if let title = item.titleFromAttributes, let folder = ensureFolder(with: title) {
-			}
+					folder.externalID = item.attributes?["nnw_externalID"] as? String
-
+					item.children?.forEach { itemChild in
-			guard let folderName = item.titleFromAttributes else {
+						if let feedSpecifier = itemChild.feedSpecifier {
-				// Folder doesn’t have a name, so it won’t be created, and its items will go one level up.
+							folder.addWebFeed(newWebFeed(with: feedSpecifier))
-				if let itemChildren = item.children {
+						}
-					loadOPMLItems(itemChildren, parentFolder: parentFolder)
+					}
-				}
-				return
-			}
-
-			if let folder = ensureFolder(with: folderName) {
-				folder.externalID = item.attributes?["nnw_externalID"] as? String
-				if let itemChildren = item.children {
-					loadOPMLItems(itemChildren, parentFolder: folder)
 				}
 			}
 		}
-
+	}
-		if let parentFolder = parentFolder {
+	
-			for feed in feedsToAdd {
+	func loadOPMLItems(_ items: [RSOPMLItem]) {
-				parentFolder.addWebFeed(feed)
+		addOPMLItems(OPMLNormalizer.normalize(items))		
-			}
-		} else {
-			for feed in feedsToAdd {
-				addWebFeed(feed)
-			}
-		}
-		
 	}
 	
 	public func markArticles(_ articles: Set<Article>, statusKey: ArticleStatus.Key, flag: Bool) -> Set<Article>? {

Frameworks/Account/Account.xcodeproj/project.pbxproj

@@ -55,6 +55,7 @@
 		5165D72A22835F7D00D9D53D /* HTMLFeedFinder.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5165D71E22835E9800D9D53D /* HTMLFeedFinder.swift */; };
 		5165D73122837F3400D9D53D /* InitialFeedDownloader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5165D73022837F3400D9D53D /* InitialFeedDownloader.swift */; };
 		5170743C232AEDB500A461A3 /* OPMLFile.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5170743B232AEDB500A461A3 /* OPMLFile.swift */; };
+		519E84A62433D49000D238B0 /* OPMLNormalizer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 519E84A52433D49000D238B0 /* OPMLNormalizer.swift */; };
 		51BB7B84233531BC008E8144 /* AccountBehaviors.swift in Sources */ = {isa = PBXBuildFile; fileRef = 51BB7B83233531BC008E8144 /* AccountBehaviors.swift */; };
 		51BC8FCC237EC055004F8B56 /* Feed.swift in Sources */ = {isa = PBXBuildFile; fileRef = 51BC8FCB237EC055004F8B56 /* Feed.swift */; };
 		51BFDECE238B508D00216323 /* ContainerIdentifier.swift in Sources */ = {isa = PBXBuildFile; fileRef = 51BFDECD238B508D00216323 /* ContainerIdentifier.swift */; };
@@ -288,6 +289,7 @@
 		5165D73022837F3400D9D53D /* InitialFeedDownloader.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = InitialFeedDownloader.swift; sourceTree = "<group>"; };
 		5170743B232AEDB500A461A3 /* OPMLFile.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OPMLFile.swift; sourceTree = "<group>"; };
 		518B2EA52351306200400001 /* Account_project_test.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; path = Account_project_test.xcconfig; sourceTree = "<group>"; };
+		519E84A52433D49000D238B0 /* OPMLNormalizer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OPMLNormalizer.swift; sourceTree = "<group>"; };
 		51BB7B83233531BC008E8144 /* AccountBehaviors.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AccountBehaviors.swift; sourceTree = "<group>"; };
 		51BC8FCB237EC055004F8B56 /* Feed.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Feed.swift; sourceTree = "<group>"; };
 		51BFDECD238B508D00216323 /* ContainerIdentifier.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ContainerIdentifier.swift; sourceTree = "<group>"; };
@@ -670,6 +672,7 @@
 				51E3EB40229AF61B00645299 /* AccountError.swift */,
 				846E77531F6F00E300A165E2 /* AccountManager.swift */,
 				5170743B232AEDB500A461A3 /* OPMLFile.swift */,
+				519E84A52433D49000D238B0 /* OPMLNormalizer.swift */,
 				84AF4EA3222CFDD100F6A800 /* AccountMetadata.swift */,
 				510BD110232C3801002692E4 /* AccountMetadataFile.swift */,
 				84F73CF0202788D80000BCEF /* ArticleFetcher.swift */,
@@ -1102,6 +1105,7 @@
 				5103A9D92422546800410853 /* CloudKitAccountDelegate.swift in Sources */,
 				5165D73122837F3400D9D53D /* InitialFeedDownloader.swift in Sources */,
 				9E784EBE237E890600099B1B /* FeedlyLogoutOperation.swift in Sources */,
+				519E84A62433D49000D238B0 /* OPMLNormalizer.swift in Sources */,
 				9EEEF71F23545CB4009E9D80 /* FeedlySendArticleStatusesOperation.swift in Sources */,
 				9EBD49C223C67784005AD5CD /* FeedlyEntryIdentifierProviding.swift in Sources */,
 				846E77541F6F00E300A165E2 /* AccountManager.swift in Sources */,

Frameworks/Account/CloudKit/CloudKitAccountDelegate.swift

@@ -128,7 +128,7 @@ final class CloudKitAccountDelegate: AccountDelegate {
 		}
 
 		BatchUpdate.shared.perform {
-			account.loadOPMLItems(children, parentFolder: nil)
+			account.loadOPMLItems(children)
 		}
 		
 		completion(.success(()))

Frameworks/Account/LocalAccount/LocalAccountDelegate.swift

@@ -85,7 +85,7 @@ final class LocalAccountDelegate: AccountDelegate {
 		}
 
 		BatchUpdate.shared.perform {
-			account.loadOPMLItems(children, parentFolder: nil)
+			account.loadOPMLItems(children)
 		}
 		
 		completion(.success(()))

Frameworks/Account/OPMLFile.swift

@@ -40,7 +40,7 @@ final class OPMLFile {
 		}
 		
 		BatchUpdate.shared.perform {
-			account.loadOPMLItems(opmlItems, parentFolder: nil)
+			account.loadOPMLItems(opmlItems)
 		}
 	}
 	

Frameworks/Account/OPMLNormalizer.swift

@@ -0,0 +1,60 @@
+//
+//  OPMLNormalizer.swift
+//  Account
+//
+//  Created by Maurice Parker on 3/31/20.
+//  Copyright © 2020 Ranchero Software, LLC. All rights reserved.
+//
+
+import Foundation
+import RSParser
+
+final class OPMLNormalizer {
+	
+	var normalizedOPMLItems = [RSOPMLItem]()
+	
+	static func normalize(_ items: [RSOPMLItem]) -> [RSOPMLItem] {
+		let opmlNormalizer = OPMLNormalizer()
+		opmlNormalizer.loadOPMLItems(items)
+		return opmlNormalizer.normalizedOPMLItems
+	}
+	
+	private func loadOPMLItems(_ items: [RSOPMLItem], parentFolder: RSOPMLItem? = nil) {
+		var feedsToAdd = [RSOPMLItem]()
+
+		items.forEach { (item) in
+
+			if let _ = item.feedSpecifier {
+				if !feedsToAdd.contains(where: { $0.feedSpecifier?.feedURL == item.feedSpecifier?.feedURL } ) {
+					feedsToAdd.append(item)
+				}
+				return
+			}
+
+			guard let _ = item.titleFromAttributes else {
+				// Folder doesn’t have a name, so it won’t be created, and its items will go one level up.
+				if let itemChildren = item.children {
+					loadOPMLItems(itemChildren, parentFolder: parentFolder)
+				}
+				return
+			}
+
+			normalizedOPMLItems.append(item)
+			if let itemChildren = item.children {
+				loadOPMLItems(itemChildren, parentFolder: item)
+			}
+		}
+
+		if let parentFolder = parentFolder {
+			for feed in feedsToAdd {
+				parentFolder.addChild(feed)
+			}
+		} else {
+			for feed in feedsToAdd {
+				normalizedOPMLItems.append(feed)
+			}
+		}
+		
+	}
+	
+}