Use async/await in flash.js

Avoid a rare race condition leading to "Error: There is already a flash in progress" messages

Changelog-entry: Avoid "Error: There is already a flash in progress" errors
Change-type: patch

.eslintrc.yml

@@ -289,7 +289,7 @@ rules:
     - error
     - anonymous: always
       named: always
-      asyncArrow: never
+      asyncArrow: always
   template-tag-spacing:
     - error
     - always

lib/gui/app/pages/main/controllers/flash.js

@@ -31,7 +31,6 @@ const availableDrives = require('../../../models/available-drives')
 const selection = require('../../../models/selection-state')
 
 module.exports = function (
-  $q,
   $state,
   $timeout,
   FlashErrorModalService,
@@ -67,39 +66,34 @@ module.exports = function (
    *
    * @param {Array<Object>} drives - list of drive objects
    * @param {Object} image - image object
-   * @returns {Promise}
+   * @returns {Promise<Boolean>}
    *
    * @example
-   * displayTailoredWarning(drives, image).then(() => {
-   *   console.log('Continue pressed')
-   * }).catch(() => {
-   *   console.log('Change pressed')
+   * displayTailoredWarning(drives, image).then((ok) => {
+   *   if (ok) {
+   *     console.log('No warning was shown or continue was pressed')
+   *   } else {
+   *     console.log('Change was pressed')
+   *   }
    * })
    */
-  const displayTailoredWarning = (drives, image) => {
-    const warningMessages = _.reduce(drives, (accumMessages, drive) => {
+  const displayTailoredWarning = async (drives, image) => {
+    const warningMessages = []
+    for (const drive of drives) {
       if (constraints.isDriveSizeLarge(drive)) {
-        return accumMessages.concat(messages.warning.largeDriveSize(drive))
+        warningMessages.push(messages.warning.largeDriveSize(drive))
       } else if (!constraints.isDriveSizeRecommended(drive, image)) {
-        return accumMessages.concat(messages.warning.unrecommendedDriveSize(image, drive))
+        warningMessages.push(messages.warning.unrecommendedDriveSize(image, drive))
       }
 
-      return accumMessages
-    }, [])
-
-    if (!warningMessages.length) {
       // TODO(Shou): we should consider adding the same warning dialog for system drives and remove unsafe mode
-      return $q.resolve()
     }
 
-    return confirmationWarningModal(warningMessages).then((value) => {
-      if (!value) {
-        DriveSelectorService.open()
-        return $q.reject()
-      }
+    if (!warningMessages.length) {
+      return true
+    }
 
-      return $q.resolve()
-    })
+    return confirmationWarningModal(warningMessages)
   }
 
   /**
@@ -118,35 +112,36 @@ module.exports = function (
    *   '/dev/disk5'
    * ])
    */
-  this.flashImageToDrive = () => {
-    const image = selection.getImage()
+  this.flashImageToDrive = async () => {
     const devices = selection.getSelectedDevices()
-
-    if (flashState.isFlashing()) {
-      return
-    }
-
+    const image = selection.getImage()
     const drives = _.filter(availableDrives.getDrives(), (drive) => {
       return _.includes(devices, drive.device)
     })
 
     const hasDangerStatus = constraints.hasListDriveImageCompatibilityStatus(drives, image)
+    if (hasDangerStatus) {
+      if (!(await displayTailoredWarning(drives, image))) {
+        DriveSelectorService.open()
+        return
+      }
+    }
 
-    const userConfirm = hasDangerStatus ? _.partial(displayTailoredWarning, drives, image) : $q.resolve
+    if (flashState.isFlashing()) {
+      return
+    }
 
     // Trigger Angular digests along with store updates, as the flash state
     // updates. Without this there is essentially no progress to watch.
     const unsubscribe = store.observe($timeout)
 
+    // Stop scanning drives when flashing
+    // otherwise Windows throws EPERM
+    driveScanner.stop()
+
     const iconPath = '../../../assets/icon.png'
-
-    userConfirm().then(() => {
-      // Stop scanning drives when flashing
-      // otherwise Windows throws EPERM
-      driveScanner.stop()
-
-      return imageWriter.flash(image.path, drives)
-    }).then(() => {
+    try {
+      await imageWriter.flash(image.path, drives)
       if (!flashState.wasLastFlashCancelled()) {
         const flashResults = flashState.getFlashResults()
         notification.send('Flash complete!', {
@@ -155,7 +150,7 @@ module.exports = function (
         })
         $state.go('success')
       }
-    }).catch((error) => {
+    } catch (error) {
       // When flashing is cancelled before starting above there is no error
       if (!error) {
         return
@@ -183,11 +178,11 @@ module.exports = function (
         FlashErrorModalService.show(messages.error.genericFlashError())
         exceptionReporter.report(error)
       }
-    }).finally(() => {
+    } finally {
       availableDrives.setDrives([])
       driveScanner.start()
       unsubscribe()
-    })
+    }
   }
 
   /**