Without the --write-to option, the "clusterctl generate cluster" command fails.

[hama-25179]

What steps did you take and what happened:
In clsuterctl built from latest source code for master branch, fail output yaml-template to stdout when running clsuterctl generate cluster.

$ kind create cluster
$ make clusterctl

$ ./bin/clusterctl version
clusterctl version: &version.Info{Major:"1", Minor:"3", GitVersion:"v1.3.0-rc.0.350-7527262d765cd5", GitCommit:"7527262d765cd5b5ad74538ce50660b23c7cf999", GitTreeState:"clean", BuildDate:"2023-01-23T01:13:33Z", GoVersion:"go1.19.3", Compiler:"gc", Platform:"linux/amd64"}

$ ./bin/clusterctl generate cluster test-cl  --kubernetes-version v1.26.0 --from test/infrastructure/docker/templates/cluster-template-development.yaml
Error: failed to write to destination file: open .: is a directory

--write-to option, output to any file works fine.

$ ./bin/clusterctl generate cluster test-cl  --kubernetes-version v1.26.0 --from test/infrastructure/docker/templates/cluster-template-development.yaml --write-to /work/cl.yaml

What did you expect to happen:
Since this command worked fine in previous versions, we hope the same result in the latest version.

Anything else you would like to add:
The output flag is added in the following PR.

• ✨ Add output flag, change printYaml function signature #7828

If this flag is not specified, the return value of filepath.Clean() is "."(dot), but it appears that this is not handled.

• https://github.com/kubernetes-sigs/cluster-api/commit/8961830d924fd5793f72d8bc6f529452030a5b4e#diff-9ba3861cc0ad513df514[…]72235715e82126528bR41-R43
• https://pkg.go.dev/path/filepath#Clean

Environment:

• clusterctl version: GitVersion:"v1.3.0-rc.0.350-7527262d765cd5"
• kind version: v0.17.0

/kind bug
/area clusterctl

[sbueringer]

Definitely a bug. Thx for testing and reporting

/triage accepted

cc @Rohitrajak1807

[Rohitrajak1807]

Definitely a bug. Thx for testing and reporting

/triage accepted

cc @Rohitrajak1807

I'll take a look. Thanks for bringing it up

[Rohitrajak1807]

/assign Rohitrajak1807
/lifecycle active

[Rohitrajak1807]

Definitely a bug. Thx for testing and reporting

/triage accepted

cc @Rohitrajak1807

Please take a look: #7972