Deserialize TextBuffers that have never been saved to disk

spec/project-spec.coffee

@@ -143,6 +143,26 @@ describe "Project", ->
       runs ->
         expect(deserializedProject.getBuffers().length).toBe 0
 
+    it "deserializes buffers that have never been saved before", ->
+      pathToOpen = path.join(temp.mkdirSync('atom-spec-project'), 'file.txt')
+
+      waitsForPromise ->
+        atom.workspace.open(pathToOpen)
+
+      runs ->
+        atom.workspace.getActiveTextEditor().setText('unsaved\n')
+        expect(atom.project.getBuffers().length).toBe 1
+
+        deserializedProject = new Project({notificationManager: atom.notifications, packageManager: atom.packages, confirm: atom.confirm})
+
+      waitsForPromise ->
+        deserializedProject.deserialize(atom.project.serialize({isUnloading: false}))
+
+      runs ->
+        expect(deserializedProject.getBuffers().length).toBe 1
+        expect(deserializedProject.getBuffers()[0].getPath()).toBe pathToOpen
+        expect(deserializedProject.getBuffers()[0].getText()).toBe 'unsaved\n'
+
     it "serializes marker layers and history only if Atom is quitting", ->
       waitsForPromise -> atom.workspace.open('a')
 

src/project.coffee

@@ -65,7 +65,11 @@ class Project extends Model
 
     handleBufferState = (bufferState) =>
       bufferState.shouldDestroyOnFileDelete ?= -> atom.config.get('core.closeDeletedFileTabs')
-      bufferState.mustExist = true
+
+      # Use a little guilty knowledge of the way TextBuffers are serialized.
+      # This allows TextBuffers that have never been saved (but have filePaths) to be deserialized, but prevents
+      # TextBuffers backed by files that have been deleted from being saved.
+      bufferState.mustExist = bufferState.digestWhenLastPersisted isnt false
 
       TextBuffer.deserialize(bufferState).catch (err) =>
         @retiredBufferIDs.add(bufferState.id)