title: Jupyter lab fails to install any extension: Assertion `data' failed
body: <p>I tried to install <code>@jupyter-widgets/jupyterlab-manager</code>:</p>
  
  <pre><code>Building jupyterlab assets (build:prod:minimize)
  An error occured.
  RuntimeError: JupyterLab failed to build
  See the log file for details:  /tmp/jupyterlab-debug-vs3sn2l7.log
  </code></pre>
  
  <p>Other extensions cannot be installed either, and give the same error. Installing from web client gives 500 error.</p>
  
  <p>I have googled around but cannot find the same error. Also, none of the solutions for similar error seem to work.</p>
  
  <p>My environment:</p>
  
  <pre><code>Raspbian GNU/Linux 10 (buster)
  
  $ node --version
  v10.15.2
  
  $ python3 -V
  Python 3.7.3
  
  $ jupyter --version
  jupyter core     : 4.6.1
  jupyter-notebook : 6.0.2
  qtconsole        : 4.6.0
  ipython          : 7.11.1
  ipykernel        : 5.1.3
  jupyter client   : 5.3.4
  jupyter lab      : 1.2.6
  nbconvert        : 5.6.1
  ipywidgets       : 7.5.1
  nbformat         : 5.0.3
  traitlets        : 4.3.3
  
  $ which jupyter
  /usr/local/bin/jupyter
  </code></pre>
  
  <p>Here is the log file:</p>
  
  <pre><code>Yarn configuration loaded.
  Node v10.15.2
  
  &gt; /usr/local/bin/npm pack @jupyter-widgets/jupyterlab-manager
  npm notice 
  npm notice   @jupyter-widgets/jupyterlab-manager@1.1.0
  npm notice === Tarball Contents === 
  npm notice 2.3kB  package.json        
  npm notice 1.5kB  LICENSE             
  npm notice 1.9kB  README.md           
  npm notice 277B   lib/index.d.ts      
  npm notice 380B   lib/index.js        
  npm notice 5.9kB  lib/manager.d.ts    
  npm notice 14.5kB lib/manager.js      
  npm notice 1.9kB  lib/output.d.ts     
  npm notice 5.2kB  lib/output.js       
  npm notice 830B   lib/plugin.d.ts     
  npm notice 7.8kB  lib/plugin.js       
  npm notice 956B   lib/renderer.d.ts   
  npm notice 3.3kB  lib/renderer.js     
  npm notice 216B   lib/semvercache.d.ts
  npm notice 862B   lib/semvercache.js  
  npm notice 375B   schema/plugin.json  
  npm notice === Tarball Details === 
  npm notice name:          @jupyter-widgets/jupyterlab-manager         
  npm notice version:       1.1.0                                       
  npm notice filename:      jupyter-widgets-jupyterlab-manager-1.1.0.tgz
  npm notice package size:  12.2 kB                                     
  npm notice unpacked size: 48.3 kB                                     
  npm notice shasum:        6196b9e3df314d488180fb5ed3bfb11df2dfdeaf    
  npm notice integrity:     sha512-2dKdzl43nMvmr[...]53y1/ADuNbzhg==    
  npm notice total files:   16                                          
  npm notice 
  jupyter-widgets-jupyterlab-manager-1.1.0.tgz
  
  Yarn configuration loaded.
  Node v10.15.2
  
  Building jupyterlab assets (build:prod:minimize)
  &gt; node /usr/local/lib/python3.7/dist-packages/jupyterlab/staging/yarn.js install --non-interactive
  yarn install v1.15.2
  [1/5] Validating package.json...
  [2/5] Resolving packages...
  [3/5] Fetching packages...
  info fsevents@1.2.11: The platform "linux" is incompatible with this module.
  info "fsevents@1.2.11" is an optional dependency and failed compatibility check. Excluding it from installation.
  [4/5] Linking dependencies...
  [5/5] Building fresh packages...
  success Saved lockfile.
  Done in 49.55s.
  
  &gt; node /usr/local/lib/python3.7/dist-packages/jupyterlab/staging/yarn.js yarn-deduplicate -s fewer
  yarn run v1.15.2
  $ /usr/local/share/jupyter/lab/staging/node_modules/.bin/yarn-deduplicate -s fewer
  Done in 15.72s.
  
  &gt; node /usr/local/lib/python3.7/dist-packages/jupyterlab/staging/yarn.js run build:prod:minimize
  yarn run v1.15.2
  $ ensure-max-old-space webpack --config webpack.prod.minimize.config.js
  /usr/bin/node[26503]: ../src/node_platform.cc:414:std::shared_ptr&lt;node::PerIsolatePlatformData&gt; node::NodePlatform::ForIsolate(v8::Isolate*): Assertion `data' failed.
  child_process.js:637
      throw err;
      ^
  
  Error: Command failed: /usr/local/share/jupyter/lab/staging/node_modules/.bin/webpack --config webpack.prod.minimize.config.js
      at checkExecSyncError (child_process.js:616:11)
      at Object.execFileSync (child_process.js:634:13)
      at Object.&lt;anonymous&gt; (/usr/local/share/jupyter/lab/staging/node_modules/@jupyterlab/buildutils/lib/ensure-max-old-space.js:38:17)
      at Module._compile (internal/modules/cjs/loader.js:689:30)
      at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)
      at Module.load (internal/modules/cjs/loader.js:599:32)
      at tryModuleLoad (internal/modules/cjs/loader.js:538:12)
      at Function.Module._load (internal/modules/cjs/loader.js:530:3)
      at Function.Module.runMain (internal/modules/cjs/loader.js:742:12)
      at startup (internal/bootstrap/node.js:283:19)
  error Command failed with exit code 1.
  info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
  
  JupyterLab failed to build
  Traceback (most recent call last):
  
    File "/usr/local/lib/python3.7/dist-packages/jupyterlab/debuglog.py", line 47, in debug_logging
      yield
  
    File "/usr/local/lib/python3.7/dist-packages/jupyterlab/labextensions.py", line 105, in start
      command=command, app_options=app_options)
  
    File "/usr/local/lib/python3.7/dist-packages/jupyterlab/commands.py", line 459, in build
      command=command, clean_staging=clean_staging)
  
    File "/usr/local/lib/python3.7/dist-packages/jupyterlab/commands.py", line 669, in build
      raise RuntimeError(msg)
  
  RuntimeError: JupyterLab failed to build
  
  Exiting application: jupyter
  </code></pre>