Bug: conftest pull breaks policy files if a file name is conflicted

[suzuki-shunsuke]

How to reproduce

$ conftest -v
Conftest: 0.53.0
OPA: 0.65.0

1. Pull a policy. https://raw.githubusercontent.com/open-policy-agent/conftest/master/examples/spdx/policy/policy.rego

conftest pull https://raw.githubusercontent.com/open-policy-agent/conftest/master/examples/spdx/policy/policy.rego

$ cat policy/policy.rego 
package main

deny[msg] {
    expected_data_license := "conftest-demo"
    input.CreationInfo.DataLicense != expected_data_license
    msg := sprintf("DataLicense should be %d, but found %d", [expected_data_license, input.CreationInfo.DataLicense])
}

2. Pull a same name policy. https://raw.githubusercontent.com/open-policy-agent/conftest/master/examples/cyclonedx/policy/policy.rego

conftest pull https://raw.githubusercontent.com/open-policy-agent/conftest/master/examples/cyclonedx/policy/policy.rego

Then the command exits successfully but the policy is broken.

$ echo $?
0

$ cat policy/policy.rego
package main

deny[msg] {
    expected_data_license := "conftest-demo"
    input.CreationInfo.DataLicense != expected_data_license
    msg := sprintf("DataLicense should be %d, but found %d", [expected_data_license, input.CreationInfo.DataLicense])
}
o expected SHA256 %s", [input.metadata.component.version, expected_shas256]
    )
}% 

Expected behaviour

There are several options.

1. Command fails and the file isn't changed
2. Command succeeds but outputs warning and the file isn't changed
3. Command succeeds but outputs warning and the file is overwritten

I think the option 1 is intuitive.

Actual behaviour

Command succeeds but breaks the file.

[boranx]

yeah, option 1 sounds reasonable. I think the governance of the policies should still be on people rather than conftest managing them due to the single responsibility principle