very basic synthesizedFolder

src/baseTypes.ts

@@ -204,6 +204,7 @@ export interface Entity {
   sizeRaw: number;
   hash?: string;
   etag?: string;
+  synthesizedFolder?: boolean;
 }
 
 export interface UploadedType {

src/remote.ts

@@ -239,7 +239,8 @@ export class RemoteClient {
   deleteFromRemote = async (
     fileOrFolderPath: string,
     cipher: Cipher,
-    remoteEncryptedKey: string = ""
+    remoteEncryptedKey: string = "",
+    synthesizedFolder: boolean = false
   ) => {
     if (this.serviceType === "s3") {
       return await s3.deleteFromRemote(
@@ -247,7 +248,8 @@ export class RemoteClient {
         this.s3Config!,
         fileOrFolderPath,
         cipher,
-        remoteEncryptedKey
+        remoteEncryptedKey,
+        synthesizedFolder
       );
     } else if (this.serviceType === "webdav") {
       return await webdav.deleteFromRemote(

src/remoteForS3.ts

@@ -250,6 +250,7 @@ const fromS3ObjectToEntity = (
     mtimeCli: mtimeCli,
     sizeRaw: x.Size!,
     etag: x.ETag,
+    synthesizedFolder: false,
   };
   return r;
 };
@@ -599,7 +600,10 @@ export const listAllFromRemote = async (
   s3Client: S3Client,
   s3Config: S3Config
 ) => {
-  return await listFromRemoteRaw(s3Client, s3Config, s3Config.remotePrefix);
+  const res = (
+    await listFromRemoteRaw(s3Client, s3Config, s3Config.remotePrefix)
+  ).filter((x) => x.keyRaw !== "" && x.keyRaw !== "/");
+  return res;
 };
 
 /**
@@ -715,11 +719,15 @@ export const deleteFromRemote = async (
   s3Config: S3Config,
   fileOrFolderPath: string,
   cipher: Cipher,
-  remoteEncryptedKey: string = ""
+  remoteEncryptedKey: string = "",
+  synthesizedFolder: boolean = false
 ) => {
   if (fileOrFolderPath === "/") {
     return;
   }
+  if (synthesizedFolder) {
+    return;
+  }
   let remoteFileName = fileOrFolderPath;
   if (!cipher.isPasswordEmpty()) {
     remoteFileName = remoteEncryptedKey;

src/sync.ts

@@ -18,6 +18,7 @@ import {
   isVaildText,
   atWhichLevel,
   mkdirpInVault,
+  getFolderLevels,
 } from "./misc";
 import {
   DEFAULT_FILE_NAME_FOR_METADATAONREMOTE,
@@ -326,7 +327,10 @@ export const ensembleMixedEnties = async (
 ): Promise<SyncPlanType> => {
   const finalMappings: SyncPlanType = {};
 
+  const synthFolders: Record<string, Entity> = {};
+
   // remote has to be first
+  // we also have to synthesize folders here
   for (const remote of remoteEntityList) {
     const remoteCopied = ensureMTimeOfRemoteEntityValid(
       await decryptRemoteEntityInplace(
@@ -352,6 +356,42 @@ export const ensembleMixedEnties = async (
       key: key,
       remote: remoteCopied,
     };
+
+    for (const f of getFolderLevels(key, true)) {
+      if (finalMappings.hasOwnProperty(f)) {
+        delete synthFolders[f];
+        continue;
+      }
+      if (
+        !synthFolders.hasOwnProperty(f) ||
+        remoteCopied.mtimeSvr! >= synthFolders[f].mtimeSvr!
+      ) {
+        synthFolders[f] = {
+          key: f,
+          keyRaw: `<synth: ${f}>`,
+          keyEnc: `<enc synth: ${f}>`,
+          size: 0,
+          sizeRaw: 0,
+          sizeEnc: 0,
+          mtimeSvr: remoteCopied.mtimeSvr,
+          mtimeSvrFmt: remoteCopied.mtimeSvrFmt,
+          mtimeCli: remoteCopied.mtimeCli,
+          mtimeCliFmt: remoteCopied.mtimeCliFmt,
+          synthesizedFolder: true,
+        };
+      }
+    }
+  }
+
+  console.debug(`synthFolders:`);
+  console.debug(synthFolders);
+
+  // special: add synth folders
+  for (const key of Object.keys(synthFolders)) {
+    finalMappings[key] = {
+      key: key,
+      remote: synthFolders[key],
+    };
   }
 
   if (Object.keys(finalMappings).length === 0 || localEntityList.length === 0) {
@@ -1074,7 +1114,12 @@ const dispatchOperationToActualV3 = async (
     );
   } else if (r.decision === "local_is_deleted_thus_also_delete_remote") {
     // local is deleted, we need to delete remote now
-    await client.deleteFromRemote(r.key, cipher, r.remote!.keyEnc);
+    await client.deleteFromRemote(
+      r.key,
+      cipher,
+      r.remote!.keyEnc,
+      r.remote!.synthesizedFolder
+    );
     await clearPrevSyncRecordByVaultAndProfile(
       db,
       vaultRandomID,
@@ -1128,7 +1173,12 @@ const dispatchOperationToActualV3 = async (
       r.decision === "folder_to_be_deleted_on_both" ||
       r.decision === "folder_to_be_deleted_on_remote"
     ) {
-      await client.deleteFromRemote(r.key, cipher, r.remote!.keyEnc);
+      await client.deleteFromRemote(
+        r.key,
+        cipher,
+        r.remote!.keyEnc,
+        r.remote!.synthesizedFolder
+      );
     }
     await clearPrevSyncRecordByVaultAndProfile(
       db,