refactor: never save mnemonic in memory unless totally necessary

Necessary cases are:
- Onboarding to show the list of 5 accounts
- In QML when we show it to the user for the backup
  - Change it to a Loader, so the component and its memory is cleaned when closed

src/app/profile/core.nim

@@ -33,7 +33,6 @@ proc init*(self: ProfileController, account: Account) =
   let profile = account.toProfileModel()
 
   let pubKey = status_settings.getSetting[string](Setting.PublicKey, "0x0")
-  let mnemonic = status_settings.getSetting[string](Setting.Mnemonic, "")
   let network = status_settings.getSetting[string](Setting.Networks_CurrentNetwork, constants.DEFAULT_NETWORK_NAME)
   let appearance = status_settings.getSetting[int](Setting.Appearance)
   profile.appearance = appearance
@@ -43,7 +42,6 @@ proc init*(self: ProfileController, account: Account) =
   self.view.addDevices(devices.getAllDevices())
   self.view.setDeviceSetup(devices.isDeviceSetup())
   self.view.setNewProfile(profile)
-  self.view.setMnemonic(mnemonic)
   self.view.setNetwork(network)
   self.view.ens.init()
 

src/app/profile/view.nim

@@ -4,6 +4,7 @@ import ../../status/profile/[mailserver, profile, devices]
 import ../../status/profile as status_profile
 import ../../status/contacts as status_contacts
 import ../../status/accounts as status_accounts
+import ../../status/libstatus/settings as status_settings
 import ../../status/status
 import ../../status/devices as status_devices
 import ../../status/ens as status_ens
@@ -19,7 +20,6 @@ QtObject:
     addedContacts*: ContactList
     blockedContacts*: ContactList
     deviceList*: DeviceList
-    mnemonic: string
     network: string
     status*: Status
     isDeviceSetup: bool
@@ -50,7 +50,6 @@ QtObject:
     result.blockedContacts = newContactList()
     result.deviceList = newDeviceList()
     result.ens = newEnsManager(status)
-    result.mnemonic = ""
     result.network = ""
     result.status = status
     result.isDeviceSetup = false
@@ -109,19 +108,13 @@ QtObject:
     read = getBlockedContacts
     notify = contactListChanged
 
-  proc mnemonicChanged*(self: ProfileView) {.signal.}
-
   proc getMnemonic*(self: ProfileView): QVariant {.slot.} =
-    return newQVariant(self.mnemonic)
-
-  proc setMnemonic*(self: ProfileView, mnemonic: string) =
-    self.mnemonic = mnemonic
-    self.mnemonicChanged()
+    # Do not keep the mnemonic in memory, so fetch it when necessary
+    let mnemonic = status_settings.getSetting[string](Setting.Mnemonic, "")
+    return newQVariant(mnemonic)
 
   QtProperty[QVariant] mnemonic:
     read = getMnemonic
-    write = setMnemonic
-    notify = mnemonicChanged
 
   proc networkChanged*(self: ProfileView) {.signal.}
 

src/nim_status_client.nim

@@ -72,17 +72,21 @@ proc mainProc() =
   var profile = profile.newController(status, changeLanguage)
   engine.setRootContextProperty("profileModel", profile.variant)
 
+  var login = login.newController(status)
+  var onboarding = onboarding.newController(status)
+
   status.events.once("login") do(a: Args):
     var args = AccountArgs(a)
+    # Delete login and onboarding from memory to remove any mnemonic that would have been saved in the accounts list
+    login.delete()
+    onboarding.delete()
+
     status.startMessenger()
     profile.init(args.account)
     wallet.init()
     chat.init()
 
 
-  var login = login.newController(status)
-  var onboarding = onboarding.newController(status)
-
   engine.setRootContextProperty("loginModel", login.variant)
   engine.setRootContextProperty("onboardingModel", onboarding.variant)
 

ui/app/AppLayouts/Profile/Sections/BackupSeedModal.qml

@@ -10,20 +10,24 @@ ModalPopup {
     //% "Write down your seed phrase"
     title: qsTrId("write-down-your-seed-phrase")
 
-    Item {
+    Loader {
+        active: popup.opened
+        width: parent.width
+        height: item.height
 
+        sourceComponent:  Component {
+            id: seedComponent
+            Item {
                 id: seed
-      anchors.left: parent.left
-      anchors.right: parent.right
                 width: parent.width
                 height: children[0].height
 
                 Rectangle {
                     id: wrapper
-        property int len: profileModel.mnemonic.split(" ").length
+                    property int len: mnemonicRepeater.count
                     anchors.top: parent.top
                     anchors.topMargin: Style.current.padding
-        height: 40*(len/2)
+                    height: 40 * (len / 2)
                     width: 350
                     border.width: 1
                     color: Style.current.background
@@ -32,15 +36,17 @@ ModalPopup {
                     anchors.horizontalCenter: parent.horizontalCenter
 
                     Repeater {
+                        id: mnemonicRepeater
                         model: profileModel.mnemonic.split(" ")
                         Rectangle {
                             id: word
                             height: 40
                             width: 175
                             color: "transparent"
-            anchors.top: (index == 0 || index == (wrapper.len/2)) ? parent.top : parent.children[index-1].bottom
-            anchors.left: (index < (wrapper.len/2)) ? parent.left : undefined
-            anchors.right: (index >= wrapper.len/2) ? parent.right : undefined
+                            anchors.top: (index == 0
+                                          || index == (wrapper.len / 2)) ? parent.top : parent.children[index - 1].bottom
+                            anchors.left: (index < (wrapper.len / 2)) ? parent.left : undefined
+                            anchors.right: (index >= wrapper.len / 2) ? parent.right : undefined
 
                             Rectangle {
                                 width: 1
@@ -50,12 +56,12 @@ ModalPopup {
                                 anchors.right: parent.right
                                 anchors.rightMargin: 175
                                 color: Style.current.inputBackground
-              visible: index >= wrapper.len/2
+                                visible: index >= wrapper.len / 2
                             }
 
                             StyledText {
                                 id: count
-              text: index+1
+                                text: index + 1
                                 color: Style.current.darkGrey
                                 anchors.bottom: parent.bottom
                                 anchors.bottomMargin: Style.current.smallPadding
@@ -74,7 +80,8 @@ ModalPopup {
                                 selectByMouse: true
                                 readOnly: true
                             }
-
+                        }
+                    }
                 }
             }
         }
@@ -83,7 +90,8 @@ ModalPopup {
     StyledText {
         id: confirmationsInfo
         //% "With this 12 words you can always get your key back. Write it down. Keep it safe, offline, and separate from this device."
-      text: qsTrId("with-this-12-words-you-can-always-get-your-key-back.-write-it-down.-keep-it-safe,-offline,-and-separate-from-this-device.")
+        text: qsTrId(
+                  "with-this-12-words-you-can-always-get-your-key-back.-write-it-down.-keep-it-safe,-offline,-and-separate-from-this-device.")
         font.pixelSize: 14
         font.weight: Font.Medium
         color: Style.current.darkGrey

ui/nim-status-client.pro

@@ -152,6 +152,7 @@ DISTFILES += \
     app/AppLayouts/Profile/LeftTab/components/MenuButton.qml \
     app/AppLayouts/Chat/data/EmojiReactions.qml \
     app/AppLayouts/Profile/Sections/AppearanceContainer.qml \
+    app/AppLayouts/Profile/Sections/BackupSeedModal.qml \
     app/AppLayouts/Profile/Sections/MyProfileContainer.qml \
     app/AppLayouts/Profile/Sections/SoundsContainer.qml \
     app/AppLayouts/Wallet/ReceiveModal.qml \