[Python] The underlying compression routine could not be loaded correctly error when deplying...

Tried running in vs code this command:

func azure functionapp publish [the function app name]


got this output:

Getting site publishing info...
[2025-04-23T12:26:20.365Z] Starting the function app deployment...
Creating archive for current directory...
Performing remote build for functions project.
Deleting the old .python_packages directory
The underlying compression routine could not be loaded correctly.
​

Validations

• Using powershell, the ls command, I validated that I was running the actual function app project I want to deploy. This is the file/folder structure for the project:

Mode LastWriteTime Length Name
---- ------------- ------ ----
d----- 4/22/2025 9:56 PM .vscode
-a---- 4/21/2025 11:12 AM 517 .gitignore
-a---- 4/21/2025 10:06 PM 391 additional_functions.py
-a---- 4/22/2025 10:11 PM 560 function_app.py
-a---- 4/21/2025 11:12 AM 302 host.json
-a---- 4/22/2025 6:13 PM 206 local.settings.json
-a---- 4/22/2025 9:39 PM 207 requirements.txt

• Checked host.json properties, see them below:

{
"version": "2.0",
"logging": {
"applicationInsights": {
"samplingSettings": {
"isEnabled": true,
"excludedTypes": "Request"
}
}
},
"extensionBundle": {
"id": "Microsoft.Azure.Functions.ExtensionBundle",
"version": "[4.*, 5.0.0)"
}
}

• Checked local.settings.json properties, see them below:

{
"IsEncrypted": false,
"Values": {
"FUNCTIONS_WORKER_RUNTIME": "python",
"AzureWebJobsFeatureFlags": "enableWorkerIndexing",
"AzureWebJobsStorage": "UseDevelopmentStorage=true"
}
}

• requirements.txt has the following module:

azure-functions

• 
  Both the function app in Azure and the local project are running on Python 3.10.
  
  
• 
  Checked the environment variables in azure for the function app, they are the following:
  

Environment Variables
APPLICATIONINSIGHTS_CONNECTION_STRING
AzureWebJobsFeatureFlags
AzureWebJobsStorage
FUNCTIONS_EXTENSION_VERSION
FUNCTIONS_WORKER_RUNTIME

• I have the latest az cli version installed:

az --version
azure-cli 2.71.0
core 2.71.0
telemetry 1.1.0
Dependencies:
msal 1.31.2b1
azure-mgmt-resource 23.1.1

• 
  Checked Azure Core Tools version, it's 4.0.7030.
  
  
• 
  Made sure I was logged in before, running az login.
  

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