[FIXED] UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 0 when deploying to Heroku

Issue

I tried to deploy my simple django project on heroku, but i couldn't understand how to solve this problem

This is the git push heroku master

remote: Traceback (most recent call last):
remote:   File "/tmp/codon/tmp/buildpacks/0f40890b54a617ec2334fac0439a123c6a0c1136/vendor/runtime-fixer", line 8, in <module>
remote:     r = f.read().strip()
remote:   File "/usr/lib/python3.8/codecs.py", line 322, in decode
remote:     (result, consumed) = self._buffer_decode(data, self.errors, final)
remote: UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 0: invalid start byte
remote: /tmp/codon/tmp/buildpacks/0f40890b54a617ec2334fac0439a123c6a0c1136/bin/steps/python: line 5: warning: command substitution: ignored null byte in input
remote: ) is not available for this stack (heroku-20).
remote:  !     Aborting.  More info: https://devcenter.heroku.com/articles/python-support
remote:  !     Push rejected, failed to compile Python app.
remote:
remote:  !     Push failed
remote:  !
remote:  ! ## Warning - The same version of this code has already been built: 898dd95ff261fc77ac4dcd00edd162d7b7c054f2
remote:  !
remote:  ! We have detected that you have triggered a build from source code with version 898dd95ff261fc77ac4dcd00edd162d7b7c054f2
remote:  ! at least twice. One common cause of this behavior is attempting to deploy code from a different branch.
remote:  !
remote:  ! If you are developing on a branch and deploying via git you must run:
remote:  !
remote:  !     git push heroku <branchname>:main
remote:  !
remote:  ! This article goes into details on the behavior:
remote:  !   https://devcenter.heroku.com/articles/duplicate-build-version
remote:
remote: Verifying deploy...
remote:
remote: !       Push rejected to portfolio-project10.
remote:
To https://git.heroku.com/portfolio-project10.git
 ! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'https://git.heroku.com/portfolio-project10.git'

C:...\portfolio-project>

It would be very nice if anyone could help me with this, or even recommending an other way to deploy django projects for free

Solution

That entire traceback is inside these parentheses: () is not available for this stack. That is the message shown when you request a Python runtime that isn't available. In this case, it looks like your runtime.txt can't even be read due to an unexpected encoding.

Delete it, then create a new file containing something like

python-3.10.2

only. Make sure it is UTF-8 encoded, commit, and redeploy.

At the moment, these are the currently supported Python versions, but the list changes as new versions are released:

• python-3.10.2
• python-3.9.10
• python-3.8.12
• python-3.7.12

Answered By - Chris