Create a new file if URL references non-existent one

app/assets/javascripts/ide/stores/actions/project.js

@@ -147,6 +147,11 @@ export const openBranch = ({ dispatch, state }, { projectId, branchId, basePath
 
         if (treeEntry) {
           dispatch('handleTreeEntryAction', treeEntry);
+        } else {
+          dispatch('createTempEntry', {
+            name: path,
+            type: 'blob',
+          });
         }
       }
     })

spec/javascripts/ide/stores/actions/project_spec.js

@@ -279,5 +279,22 @@ describe('IDE store project actions', () => {
         .then(done)
         .catch(done.fail);
     });
+
+    it('creates a new file supplied via URL if the file does not exist yet', done => {
+      openBranch(store, { ...branch, basePath: 'not-existent.md' })
+        .then(() => {
+          expect(store.dispatch).not.toHaveBeenCalledWith(
+            'handleTreeEntryAction',
+            jasmine.anything(),
+          );
+
+          expect(store.dispatch).toHaveBeenCalledWith('createTempEntry', {
+            name: 'not-existent.md',
+            type: 'blob',
+          });
+        })
+        .then(done)
+        .catch(done.fail);
+    });
   });
 });