Python Flask import Error of module that isn´t being imported

Question

I have a flask app running in Google App Engine. Yesterday, I deployed a new version of my app where I only change the HTML style. It deployed as it was supposed to. Today, I realized that I didn't change the title for each corresponding HTML page, so I only changed the title tag in each HTML page. I deployed the app again and now I'm getting this strange error of an Import Error for a module that I have never even used. How can I fix this?

The error:

ImportError: cannot import name 'json' from 'itsdangerous' (/layers/google.python.pip/pip/lib/python3.7/site-packages/itsdangerous/__init__.py)

EDIT FEB 24, 2022:

as you can see, the original folder to python3.7 has been replaced with python3.9

Is this normal in GAE?

Blockhouse

Answer 1

This issue on Flask's GitHub is related.

Either update to Flask>2, or if that's not possible pin ItsDangerous<2 and MarkupSafe<2.

To pin to lower versions in a requirements.txt file:

flask==1.1.4
itsdangerous==1.1.0
markupsafe==1.1.1

Minnaminnaminnie

thank you! What had happend also was the that in the traceback, the directory says python3.7 which is the version I have always used. When I search the folder for python 3.7, Google App Engine last night had replaced it with python3.9....do you know if this always happens like this without warning? – Blockhouse

Do you mean that the version of your App Engine service changed? It shouldn't as the runtime is defined on runtime configuration item from the app.yaml file. – Aubervilliers

yes sir it did....the app.yaml had not changed from its original 3.7 as i had left it.....but python version 3.7 was no longer in my cloud shell....there is only 2 folders...one that says Python2.7 and Python3.9....really weird :( – Blockhouse

if this happens again I suggest to write the details it on another post on Stack or even report it on Googles issue tracker – Aubervilliers

Thank you!! I was pulling my hair out about this error! – Oyster

Answer 2

I had the same issue today. I was using flask=1.1.2, and when I updated the version to flask==2.0.3, the import issue was resolved.

Consol

I tried this and in fact worked for fixing the issue originally stated. But later in my code I had an operation with .__dict__ property. Broke there because keys are not the same as in 1.1.2. For making things work without changing my code for the moment, stick to keep using flask=1.1.2 and added these to requirements.txt: itsdangerous==1.1.0 markupsafe==1.1.1. – Broderic

Answer 3

This is caused by changes in Flask dependencies. Another question about this was asked on ServerFault.

You can either upgrade to Flask>2, or I had to downgrade to itsdangerous==2.0.1 if you can't do that.

Feliks

Answer 4

the deprecation is performed with itsdangerous > 2.0.1.

Review