az storage blob upload can overwrite a blob without needing the --overwrite parameter in az cli version 2.33.1 , however in version 2.34.1 it requires the overwrite parameter.

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Describe the bug

Command Name az storage blob upload

Detailed command

az storage blob upload --account-name <my-storage-account> --container-name '$web' --file <my-file> --auth-mode login Errors:

The specified blob already exists.
RequestId:xxxx-xxxxx-xxxx
Time:2022-03-24T04:01:57.5064729Z
ErrorCode:BlobAlreadyExists
If you want to overwrite the existing one, please add --overwrite in your command.

To Reproduce:

Steps to reproduce the behavior. Note that argument values have been redacted, as they may contain sensitive information.

• Install the latest azure cli on your workstation - As of raising this bug this is v2.34.1
• Attempt to overwrite an existing blob in a container
• az storage blob upload --account-name <my-storage-account> --container-name ‘$web’ --file <my-file> --auth-mode login
• You will get the error The specified blob already exists
• Now install the version v2.33.1 of azure cli and try the same steps as above
• The file can be re-uploaded/overwritten again and again without any error.
• So in summary:
  • If you have azure cli v2.33.1 - az storage blob upload allows the upload of the same file to the same location allowing it to be overwritten.
  • if you have azure cli v2.34.1 - az storage blob upload doesn’t allow the upload of the same file to the same location, instead throws an error Blob already exists and requires the experimental parameter --overwrite to be supplied.

Expected Behavior

• I don’t expect this breaking change to be introduced. Azure CLI tasks ( for azure pipelines ) is using azure CLI v2.33.1 and the file upload works smoothly, but I am afraid as soon as the Azure CLI task gets upgraded to v2.34.1 my pipeline code will break.

Environment Summary

Windows-10-10.0.19041-SP0
Python 3.8.9
Installer: MSI

azure-cli 2.34.1

Extensions:
azure-devops 0.22.0
desktopvirtualization 0.1.1
interactive 0.4.5
log-analytics 0.2.2
next 0.1.2
rdbms-connect 1.0.1

Dependencies:
msal 1.16.0
azure-mgmt-resource 20.0.0

Additional Context

[norb62]

This change breaks every piece of 3rd party code using upload or upload-batch as soon as the az client is updated to 2.34.1 or higher. To workaround this, I need to manually detect the az version, then issue 2 different commands, depending on the version, since the --overwrite option does not exist in az storage upload before 2.34.1. It’s not optimal imo.

–overwrite should be true by default and when not specified, to ensure backward compatibility. If a user wants to ensure that its data can’t be overwritten, it could specify --overwrite false.

[calvinhzy]

We have included this as a breaking change in 2.34.1 as we think it is dangerous to overwrite files silently. --overwrite needs to be specified to overwrite files. Sorry for the inconvenience. https://docs.microsoft.com/en-us/cli/azure/storage/blob?view=azure-cli-latest#az-storage-blob-upload