Attempt to get merging of zfs options in zpool setup working

I have not yet tested addition of new datasets, or the removal/
unmounting of newly disappeared datasets.

rust/program/zpool-setup/src/cli.rs

@@ -1,6 +1,6 @@
-use std::{borrow::Cow, collections::BTreeMap, path::PathBuf, str::FromStr};
+use std::{borrow::Cow, collections::BTreeMap, ops::Deref, path::PathBuf, str::FromStr};
 
-use serde::Deserialize;
+use serde::{Deserialize, Serialize};
 
 use crate::disk_mapping::DiskMapping;
 
@@ -52,7 +52,7 @@ impl Vdev {
 
 #[derive(Clone, Debug, Deserialize)]
 #[serde(transparent)]
-pub struct Vdevs(pub Vec<Vdev>);
+pub struct Vdevs(Vec<Vdev>);
 
 impl FromStr for Vdevs {
     type Err = anyhow::Error;
@@ -62,9 +62,17 @@ impl FromStr for Vdevs {
     }
 }
 
-#[derive(Clone, Debug, Deserialize)]
+impl Deref for Vdevs {
+    type Target = Vec<Vdev>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+#[derive(Clone, Debug, Default, Deserialize, Serialize, PartialEq)]
 #[serde(transparent)]
-pub struct Options(pub BTreeMap<String, String>);
+pub struct Options(BTreeMap<String, String>);
 
 impl FromStr for Options {
     type Err = anyhow::Error;
@@ -73,13 +81,36 @@ impl FromStr for Options {
         common::json::from_str(s)
     }
 }
+impl Deref for Options {
+    type Target = BTreeMap<String, String>;
 
-#[derive(Clone, Debug, Deserialize)]
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+#[derive(Clone, Debug, Default, Deserialize, Serialize, PartialEq)]
 pub struct Dataset {
     pub options: Options,
     pub mountpoint: Option<PathBuf>,
 }
 
+impl Dataset {
+    pub fn without_mountpoint(&self) -> Dataset {
+        Self {
+            mountpoint: None,
+            options: self.options.clone(),
+        }
+    }
+
+    pub fn with_options(options: &Options) -> Self {
+        Self {
+            mountpoint: None,
+            options: options.clone(),
+        }
+    }
+}
+
 #[derive(Clone, Debug, Deserialize)]
 #[serde(transparent)]
 pub struct Datasets(pub BTreeMap<String, Dataset>);