Add a Diff Visitor for BlueprintZoneConfigs

Cargo.toml

@@ -687,7 +687,7 @@ zone = { version = "0.3", default-features = false, features = ["async"] }
 # the kinds). However, uses of omicron-uuid-kinds _within omicron_ will have
 # std and the other features enabled because they'll refer to it via
 # omicron-uuid-kinds.workspace = true.
-newtype-uuid = { version = "1.1.3", default-features = false }
+newtype-uuid = { version = "1.2.1", default-features = false }
 omicron-uuid-kinds = { path = "uuid-kinds", features = ["serde", "schemars08", "uuid-v4"] }
 
 # NOTE: The test profile inherits from the dev profile, so settings under

common/src/api/external/mod.rs

@@ -751,10 +751,27 @@ impl From<ByteCount> for i64 {
     PartialEq,
     PartialOrd,
     Serialize,
-    Diffus,
 )]
 pub struct Generation(u64);
 
+// We have to manually implement `Diffable` because this is newtype with private
+// data, and we want to see the diff on the newtype not the inner data.
+impl<'a> Diffable<'a> for Generation {
+    type Diff = (&'a Generation, &'a Generation);
+
+    fn diff(&'a self, other: &'a Self) -> edit::Edit<'a, Self> {
+        if self == other {
+            edit::Edit::Copy(self)
+        } else {
+            edit::Edit::Change {
+                before: self,
+                after: other,
+                diff: (self, other),
+            }
+        }
+    }
+}
+
 impl Generation {
     pub const fn new() -> Generation {
         Generation(1)
@@ -1947,7 +1964,11 @@ impl<'a> Diffable<'a> for MacAddr {
         if self == other {
             edit::Edit::Copy(self)
         } else {
-            edit::Edit::Change((self, other))
+            edit::Edit::Change {
+                before: self,
+                after: other,
+                diff: (self, other),
+            }
         }
     }
 }

nexus/types/src/deployment.rs

@@ -54,6 +54,7 @@ use strum::IntoEnumIterator;
 mod blueprint_diff;
 mod blueprint_display;
 mod clickhouse;
+pub mod diff_visitors;
 pub mod execution;
 pub mod id_map;
 mod network_resources;
@@ -62,6 +63,7 @@ mod tri_map;
 mod zone_type;
 
 pub use clickhouse::ClickhouseClusterConfig;
+pub use diff_visitors::BpVisitorContext;
 pub use network_resources::AddNetworkResourceError;
 pub use network_resources::OmicronZoneExternalFloatingAddr;
 pub use network_resources::OmicronZoneExternalFloatingIp;

nexus/types/src/deployment/diff_visitors.rs

@@ -0,0 +1,55 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+//! An API for visiting diffs between blueprints generated via [diffus](https://github.com/oxidecomputer/diffus)
+//!
+//! Modelled after [`syn::visit`](https://docs.rs/syn/1/syn/visit).
+
+pub mod visit_blueprint_zones_config;
+
+use diffus::edit::enm;
+use omicron_uuid_kinds::{OmicronZoneUuid, SledUuid};
+
+use super::{
+    BlueprintZoneConfig, BlueprintZoneDisposition, BlueprintZoneType,
+    BlueprintZonesConfig, EditedBlueprintZoneConfig,
+};
+
+/// A context for blueprint related visitors
+#[derive(Debug, Clone, Default)]
+pub struct BpVisitorContext {
+    pub sled_id: Option<SledUuid>,
+    pub zone_id: Option<OmicronZoneUuid>,
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct Change<'e, T> {
+    pub before: &'e T,
+    pub after: &'e T,
+}
+
+impl<'e, T> Change<'e, T> {
+    pub fn new(before: &'e T, after: &'e T) -> Change<'e, T> {
+        Change { before, after }
+    }
+}
+
+impl<'e, T> From<(&'e T, &'e T)> for Change<'e, T> {
+    fn from(value: (&'e T, &'e T)) -> Self {
+        Change::new(value.0, value.1)
+    }
+}
+
+impl<'e, T, Diff> From<&enm::Edit<'e, T, Diff>> for Change<'e, T> {
+    fn from(value: &enm::Edit<'e, T, Diff>) -> Self {
+        match value {
+            enm::Edit::VariantChanged(before, after) => {
+                Change::new(before, after)
+            }
+            enm::Edit::AssociatedChanged { before, after, .. } => {
+                Change::new(before, after)
+            }
+        }
+    }
+}