Heroku Not Reading Requirement.txt File

I am trying to deploy my python flask app to heroku but it keeps crashing and complaining about bash: gunicorn: command not found. I have my requirement.txt file in the root folder

Solution 1:

I faced a similar problem with my app. I just reset all my requirements by sending in an empty requirements.txt file. Then built my app. Then sent the original file. I don't understand why, but it worked.

Solution 2:

I am also having a similar problem like this on Heroku. I created an IDENTICAL new project and magically it works. Heroku has some bug related to ignoring requirements.txt

Solution 3:

I fixed it by creating a new environment in Heroku. The previous environment seems not to be reading the requirement.txt file, I couldn't figure why.