Elyra container image that was built from master fails with `webbrowser.Error: could not locate runnable browser`

Describe the issue See error message

To Reproduce Steps to reproduce the behavior:

1. git clone https://github.com/elyra-ai/elyra.git
2. cd elyra
3. make container-image
4. docker run -it -p 8888:8888 elyra/elyra:dev jupyter lab

Screenshots or log output If applicable, add screenshots or log output to help explain your problem.

Log Output

**Note: Removing dead /tmp/elyra/packages/python-editor "@elyra/theme-extension"
**Note: Removing dead /tmp/elyra/packages/python-editor "@elyra/code-snippet-extension"
**Note: Removing dead /tmp/elyra/packages/python-editor "@elyra/metadata-extension"
**Note: Removing dead /tmp/elyra/packages/python-editor "@elyra/pipeline-editor-extension"
**Note: Removing dead /tmp/elyra/packages/python-editor "@elyra/python-editor-extension"
**Note: Removing dead /tmp/elyra/packages/metadata-common "@elyra/services"
**Note: Removing dead /tmp/elyra/packages/metadata-common "@elyra/ui-components"
**Note: Removing dead /tmp/elyra/packages/metadata-common "@elyra/metadata-common"
Removing orphaned linked package @elyra/services
Removing orphaned linked package @elyra/metadata-common
Removing orphaned linked package @elyra/ui-components
Generating grammar tables from /opt/conda/lib/python3.8/site-packages/blib2to3/Grammar.txt
Writing grammar tables to /home/jovyan/.cache/black/20.8b1/Grammar3.8.6.final.0.pickle
Writing failed: [Errno 2] No such file or directory: '/home/jovyan/.cache/black/20.8b1/tmprft725mx'
Generating grammar tables from /opt/conda/lib/python3.8/site-packages/blib2to3/PatternGrammar.txt
Writing grammar tables to /home/jovyan/.cache/black/20.8b1/PatternGrammar3.8.6.final.0.pickle
Writing failed: [Errno 2] No such file or directory: '/home/jovyan/.cache/black/20.8b1/tmpj2jpmoq0'
[I 2021-02-22 16:37:21.296 ServerApp] elyra | extension was successfully linked.
[I 2021-02-22 16:37:21.296 ServerApp] jupyter_lsp | extension was successfully linked.
[I 2021-02-22 16:37:21.296 ServerApp] jupyter_resource_usage | extension was successfully linked.
[I 2021-02-22 16:37:21.314 ServerApp] jupyterlab | extension was successfully linked.
[I 2021-02-22 16:37:21.314 ServerApp] jupyterlab_git | extension was successfully linked.
[W 2021-02-22 16:37:21.321 NotebookApp] 'ip' has moved from NotebookApp to ServerApp. This config will be passed to ServerApp. Be sure to update your config before our next release.
[W 2021-02-22 16:37:21.321 NotebookApp] 'port' has moved from NotebookApp to ServerApp. This config will be passed to ServerApp. Be sure to update your config before our next release.
[W 2021-02-22 16:37:21.322 NotebookApp] 'port' has moved from NotebookApp to ServerApp. This config will be passed to ServerApp. Be sure to update your config before our next release.
[I 2021-02-22 16:37:21.330 ServerApp] Writing notebook server cookie secret to /home/jovyan/.local/share/jupyter/runtime/jupyter_cookie_secret
[I 2021-02-22 16:37:21.776 ServerApp] nbgitpuller | extension was found and enabled by nbclassic. Consider moving the extension to Jupyter Server's extension paths.
[I 2021-02-22 16:37:21.776 ServerApp] nbgitpuller | extension was successfully linked.
[I 2021-02-22 16:37:21.776 ServerApp] nbclassic | extension was successfully linked.
[I 2021-02-22 16:37:21.776 ServerApp] nbdime | extension was successfully linked.
[I 2021-02-22 16:37:21.879 ServerApp] Registering processor "EntryPoint('airflow', 'elyra.pipeline.processor_airflow', 'AirflowPipelineProcessor', Distribution('elyra', '2.1.0.dev0'))" with type -> airflow
[I 2021-02-22 16:37:21.880 ServerApp] Registering processor "EntryPoint('kfp', 'elyra.pipeline.processor_kfp', 'KfpPipelineProcessor', Distribution('elyra', '2.1.0.dev0'))" with type -> kfp
[I 2021-02-22 16:37:21.880 ServerApp] Registering processor "EntryPoint('local', 'elyra.pipeline.processor_local', 'LocalPipelineProcessor', Distribution('elyra', '2.1.0.dev0'))" with type -> local
[I 2021-02-22 16:37:21.881 ServerApp] elyra | extension was successfully loaded.
[I 2021-02-22 16:37:22.015 ServerApp] jupyter_lsp | extension was successfully loaded.
[I 2021-02-22 16:37:22.016 ServerApp] jupyter_resource_usage | extension was successfully loaded.
[I 2021-02-22 16:37:22.018 LabApp] JupyterLab extension loaded from /opt/conda/lib/python3.8/site-packages/jupyterlab
[I 2021-02-22 16:37:22.018 LabApp] JupyterLab application directory is /opt/conda/share/jupyter/lab
[I 2021-02-22 16:37:22.022 ServerApp] jupyterlab | extension was successfully loaded.
[I 2021-02-22 16:37:22.025 ServerApp] jupyterlab_git | extension was successfully loaded.
[I 2021-02-22 16:37:22.031 ServerApp] nbclassic | extension was successfully loaded.
[I 2021-02-22 16:37:22.148 ServerApp] nbdime | extension was successfully loaded.
[I 2021-02-22 16:37:22.150 ServerApp] nbgitpuller | extension was successfully loaded.
[I 2021-02-22 16:37:22.150 ServerApp] Serving notebooks from local directory: /home/jovyan
[I 2021-02-22 16:37:22.150 ServerApp] Jupyter Server 1.4.0 is running at:
[I 2021-02-22 16:37:22.150 ServerApp] http://1e2862c63702:8888/lab?token=fb52cde7485ba71eb37faa862296b58e7a0d0dc17ff56020
[I 2021-02-22 16:37:22.151 ServerApp]  or http://127.0.0.1:8888/lab?token=fb52cde7485ba71eb37faa862296b58e7a0d0dc17ff56020
[I 2021-02-22 16:37:22.151 ServerApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
Traceback (most recent call last):
  File "/opt/conda/lib/python3.8/site-packages/jupyter_server/serverapp.py", line 2018, in launch_browser
    browser = webbrowser.get(self.browser or None)
  File "/opt/conda/lib/python3.8/webbrowser.py", line 65, in get
    raise Error("could not locate runnable browser")
webbrowser.Error: could not locate runnable browser
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File “/opt/conda/bin/jupyter-lab”, line 8, in <module>
sys.exit(main())
File “/opt/conda/lib/python3.8/site-packages/jupyter_server/extension/application.py”, line 520, in launch_instance
serverapp.start()
File “/opt/conda/lib/python3.8/site-packages/jupyter_server/serverapp.py”, line 2100, in start
self.start_app()
File “/opt/conda/lib/python3.8/site-packages/jupyter_server/serverapp.py”, line 2059, in start_app
self.launch_browser()
File “/opt/conda/lib/python3.8/site-packages/jupyter_server/serverapp.py”, line 2020, in launch_browser
self.log.warning((‘No web browser found: %s.’) % e)
UnboundLocalError: local variable '’ referenced before assignment

Expected behavior A clear and concise description of what you expected to happen.

Deployment information Describe what you’ve deployed and how:

• Elyra version: 2.1 (master branch)
• Operating system: macos
• Installation source: custom container image built from master
• Deployment type: Docker, Kubernetes

[kevin-bates]

This is due to a recent issue in Jupyter Server. A patch release is being cut today.

[ptitzler]

I am running with Jupyter server 1.2.2 and git 0.30.0b1 and am observing the same error message., which appears to be a known problem: https://github.com/jupyterlab/jupyterlab-git/issues/842.

I think we can go ahead and close this issue. Thanks for verifying Kevin!