# use empty policy flag values to unset

Treat provided empty checkpoint policy flag values as field removal.

This keeps the command surface smaller while preserving the ability to distinguish omitted flags from explicit empty values.

## Sessions

## Changes

5

- cmd/entire/cli

- Mcheckpoint_policy.go+22/-19

- Mcheckpoint_policy_test.go+3/-8

- checkpointpolicy

- Mupdate.go+9/-28

- Mupdate_test.go+33/-17

```
10 unmodified lines

```go

type checkpointPolicyOptions struct {
	version         string
	minVersion      string
	unsetVersion    bool
	unsetMinVersion bool
	force           bool
	version         string
	minVersion      string
	force           bool
}

const (
	checkpointVersionFlag    = "checkpoint-version"
	checkpointMinVersionFlag = "checkpoint-min-version"
)

func newCheckpointPolicyCmd() *cobra.Command {
	var opts checkpointPolicyOptions
	cmd := &cobra.Command{
		Hidden: true,
		Args:   cobra.NoArgs,
		RunE: func(cmd *cobra.Command, _ []string) error {
		},
	}

cmd.Flags().StringVar(&opts.version, "checkpoint-version", "", "Set the checkpoint version used for new writes")
	cmd.Flags().StringVar(&opts.minVersion, "checkpoint-min-version", "", "Set the checkpoint version used for upgrade warnings")
	cmd.Flags().BoolVar(&opts.unsetVersion, "unset-checkpoint-version", false, "Unset checkpoint_version so new writes use the CLI default")
	cmd.Flags().BoolVar(&opts.unsetMinVersion, "unset-checkpoint-min-version", false, "Unset checkpoint_min_version so upgrade warnings use the CLI default")
	cmd.Flags().StringVar(&opts.version, checkpointVersionFlag, "", `Set the checkpoint version used for new writes. Use "" to unset`)
	cmd.Flags().StringVar(&opts.minVersion, checkpointMinVersionFlag, "", `Set the checkpoint version used for upgrade warnings. Use "" to unset`)
	cmd.Flags().BoolVar(&opts.force, "force", false, "Allow checkpoint policy version downgrades")
	return cmd
}
```

checkpoint_version selects the checkpoint metadata format used for new writes.
If no policy is configured, Entire uses the CLI default. If this CLI reads a
configured checkpoint_version it cannot write, it warns and writes the default
version instead. Unset checkpoint_version to inherit the CLI default.

checkpoint_min_version is an upgrade nudge. Clients that cannot read that
version warn users to upgrade, but policy alone does not block checkpoint writes
or app usage. Unset checkpoint_min_version to inherit the CLI default.

```go

func hasCheckpointPolicyUpdate(opts checkpointPolicyOptions) bool {
	return opts.version != "" || opts.minVersion != "" || opts.unsetVersion || opts.unsetMinVersion
}
```

Either field may be omitted. An empty policy file means both fields inherit the
CLI defaults:

```json
{}
```

`checkpoint_version` selects the checkpoint format for new writes. If no policy
is configured, or a policy omits `checkpoint_version`, the CLI writes its
default checkpoint version. If another client configures a `checkpoint_version`
this CLI cannot write, the CLI warns and writes the default checkpoint version instead.

`checkpoint_min_version` is a soft upgrade nudge. Clients that cannot read that
version warn users to upgrade, but policy alone does not block checkpoint
writes or app usage. Missing policy fields default to `branch-v1`.