Spyder: nbconvert is reported as a missing dependency

[al3xsh]

Issue Report Checklist

• [x] Searched the issues page for similar reports
• [x] Read the relevant sections of the Spyder Troubleshooting Guide and followed its advice
• [x] Reproduced the issue after updating with conda update spyder (or pip, if not using Anaconda)
• [ ] Could not reproduce inside jupyter qtconsole (if console-related)
• [x] Tried basic troubleshooting (if a bug/error)
  
  
  
  • [x] Restarted Spyder
  
  
  • [x] Reset preferences with spyder --reset
  
  
  • [x] Reinstalled the latest version of Anaconda
  
  
  • [x] Tried the other applicable steps from the Troubleshooting Guide
  
  
• [x] Completed the Problem Description, Steps to Reproduce and Version sections below

Problem Description

When I start spyder I get a message that I have missing dependencies:

nbconvert >=4.0: None (NOK)

despite having version 5.3.1 installed (via conda)

What steps reproduce the problem?

1. conda create --name test python=3.7 && conda activate test
2. conda install spyder
3. spyder

What is the expected output? What do you see instead?

Expected output is no error.

What I see is:

Versions

• Spyder version: 3.3.3
• Python version: 3.7
• Qt version: 5.9.7-h5867ecd_1
• PyQt version: 5.9.2-py37h05f1152_2
• Operating System name/version: Ubuntu 18.04

[al3xsh]

Although nbconvert is installed (and everything was installed on a completely fresh version of Anaconda), when I open python and try to import nbconvert I get:

>>> import nbconvert
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/alex/code/development_tools/anaconda3/envs/test/lib/python3.7/site-packages/nbconvert/__init__.py", line 7, in <module>
    from . import postprocessors
  File "/home/alex/code/development_tools/anaconda3/envs/test/lib/python3.7/site-packages/nbconvert/postprocessors/__init__.py", line 5, in <module>
    from .serve import ServePostProcessor
  File "/home/alex/code/development_tools/anaconda3/envs/test/lib/python3.7/site-packages/nbconvert/postprocessors/serve.py", line 19, in <module>
    class ProxyHandler(web.RequestHandler):
  File "/home/alex/code/development_tools/anaconda3/envs/test/lib/python3.7/site-packages/nbconvert/postprocessors/serve.py", line 21, in ProxyHandler
    @web.asynchronous
AttributeError: module 'tornado.web' has no attribute 'asynchronous'

Do you think this could be the issue?

Regards,

Alex

[ccordoba12]

Thanks for reporting. This is an issue with the nbconvert conda packages.

[ccordoba12]

Pinging @jjhelmus about this one. @jjhelmus, it seems you need to unpin pandoc in the nbconvert recipe to make conda install the latest nbconvert, which is the one compatible with the latest tornado.

See

https://github.com/conda-forge/nbconvert-feedstock/issues/27
https://github.com/conda-forge/nbconvert-feedstock/pull/28

[al3xsh]

Thanks,

Running conda install nbconvert upgraded nbconvert to 5.4.1 and the error went away!

Regards,

Alex

[jjhelmus]

@ccordoba12 A new build of nbconvert 5.4.1 is available in defaults that unpins the pandoc dependency.

[ccordoba12]

Thanks a lot @jjhelmus!

[NaderNazemi]

Please help, I tried installing nbconvert using conda, but it fails by saying "requests" is a dependency and and cannot be removed.
This all started when I downgraded "tornado" to an older version.
Also when I type "conda list", I am getting an error.

[ngayraud]

Still doing this for me today, after installing the new spyder version through conda. I am getting the AttributeError: module 'tornado.web' has no attribute 'asynchronous' error. Any ideas?