As a project owner, you'd expect unfettered access to all resources within your Google Cloud project. However, there exists a peculiar scenario where project owners can list objects but can't perform operations like cp, acl get, or even access through Cloud Console. Here's what's happening under the hood:

# Typical error message
gsutil acl get gs://my-bucket/restricted-object
AccessDeniedException: Access denied. Please ensure you have OWNER permission 
on gs://my-bucket/restricted-object

When facing this situation, consider these technical possibilities:

# Verify project-level permissions
gcloud projects get-iam-policy $PROJECT_ID --format=json | jq '.bindings[] 
| select(.role=="roles/owner")'

Common triggers for this behavior include:

• Object Hold: Legal hold or retention policy preventing modifications
• Bucket Policy Only: Bucket using IAM uniform permissions
• Custom Roles: Conflicting permission assignments
• ACL Inheritance Break: Object-specific ACL override

Let's examine diagnostic commands to pinpoint the issue:

# Check bucket IAM permissions
gsutil iam get gs://$MYBUCKET

# Inspect object ACLs (if accessible)
gsutil acl get gs://$MYBUCKET/$SOMEOBJECT

# Verify retention configuration
gsutil retention get gs://$MYBUCKET

# Check for holds
gsutil stat gs://$MYBUCKET/$SOMEOBJECT | grep -E "Retention|Hold"

For each identified cause, here are resolution patterns:

# Case 1: Object under retention
gsutil retention temp set gs://$MYBUCKET/$SOMEOBJECT

# Case 2: Bucket Policy Only conflict
gsutil bucketpolicyonly set off gs://$MYBUCKET

# Case 3: ACL restoration
gsutil acl ch -u projectOwner-$PROJECT_ID:O gs://$MYBUCKET/$SOMEOBJECT

Remember that some operations may require additional privileges or service account impersonation:

# Using service account with proper permissions
gcloud auth activate-service-account --key-file=credentials.json
gsutil cp gs://$MYBUCKET/$SOMEOBJECT ./local_copy

Implement these best practices to avoid recurrence:

• Enable Cloud Audit Logs for bucket operations
• Set up Organization Policy Constraints
• Regularly review IAM permissions hierarchy
• Implement Terraform or Deployment Manager for consistent permission sets

When standard methods fail, try these approaches:

# Use --debug flag with gsutil
gsutil --debug cp gs://$MYBUCKET/$SOMEOBJECT ./debug_copy

# Check Cloud Logging with advanced filters
logName:"projects/$PROJECT_ID/logs/cloudaudit.googleapis.com"
protoPayload.authenticationInfo.principalEmail:"your-email@domain.com"
protoPayload.methodName:"storage.objects.get"

As a project owner in Google Cloud, you'd expect full access to all resources. But sometimes, you encounter objects that respond to gsutil ls but throw AccessDeniedException when trying to:

gsutil cp gs://my-bucket/restricted-object ./local-file
# Returns:
# AccessDeniedException: 403 Access denied

This typically occurs when:

• The object has object-level ACLs overriding bucket permissions
• The bucket uses uniform bucket-level access but the object was created before enabling it
• There are organization policy constraints in place

First, verify your effective permissions:

# Check bucket IAM policy
gsutil iam get gs://my-bucket

# Check object ACL (if possible)
gsutil acl get gs://my-bucket/restricted-object

# Check organization policies
gcloud resource-manager org-policies list --project=PROJECT_ID

Case 1: Object ACL Conflict

When object ACLs restrict access even to owners:

# Solution 1: Reset ACLs (requires storage.admin role)
gsutil acl ch -u PROJECT_OWNER:OWNER gs://my-bucket/restricted-object

# Solution 2: Recursive fix for multiple objects
gsutil -m acl ch -R -u PROJECT_OWNER:OWNER gs://my-bucket/

Case 2: Uniform Access Transition

For buckets that recently enabled uniform access:

# 1. Temporarily disable uniform access
gsutil uniformbucketlevelaccess set off gs://my-bucket

# 2. Fix ACLs
gsutil acl ch -R -u PROJECT_OWNER:OWNER gs://my-bucket/

# 3. Re-enable uniform access
gsutil uniformbucketlevelaccess set on gs://my-bucket

• Always use uniform bucket-level access from project creation
• Set organization policies to prevent object-level ACL modifications
• Implement bucket IAM conditions for fine-grained control

Here's a Python script to identify problematic objects:

from google.cloud import storage

def check_object_access(bucket_name):
    storage_client = storage.Client()
    bucket = storage_client.bucket(bucket_name)
    
    for blob in bucket.list_blobs():
        try:
            if not blob.exists():
                print(f"Access issue with {blob.name}")
        except Exception as e:
            print(f"Error on {blob.name}: {str(e)}")

check_object_access("my-bucket")