feat(governance): New proposal type: TakeCanisterSnapshot.

rs/nns/governance/api/src/types.rs

@@ -4200,6 +4200,12 @@ pub enum NnsFunction {
     /// UpdateConfigOfSubnet can be used instead. But otherwise, this is the
     /// state of the art (as of Oct 2025) way of doing subnet recovery.
     SetSubnetOperationalLevel = 55,
+    /// Does what the name says: takes a canister snapshot.
+    ///
+    /// The canister being snapshotted (the "target" canister) must be
+    /// controlled by the NNS Root canister. This restriction could be relaxed
+    /// later. See nns/.../root.did for the payload type.
+    TakeCanisterSnapshot = 56,
 }
 impl NnsFunction {
     /// String value of the enum field names used in the ProtoBuf definition.
@@ -4283,6 +4289,7 @@ impl NnsFunction {
             NnsFunction::PauseCanisterMigrations => "NNS_FUNCTION_PAUSE_CANISTER_MIGRATIONS",
             NnsFunction::UnpauseCanisterMigrations => "NNS_FUNCTION_UNPAUSE_CANISTER_MIGRATIONS",
             NnsFunction::SetSubnetOperationalLevel => "NNS_FUNCTION_SET_SUBNET_OPERATIONAL_LEVEL",
+            NnsFunction::TakeCanisterSnapshot => "NNS_FUNCTION_TAKE_CANISTER_SNAPSHOT",
         }
     }
     /// Creates an enum from field names used in the ProtoBuf definition.
@@ -4363,6 +4370,7 @@ impl NnsFunction {
             "NNS_FUNCTION_PAUSE_CANISTER_MIGRATIONS" => Some(Self::PauseCanisterMigrations),
             "NNS_FUNCTION_UNPAUSE_CANISTER_MIGRATIONS" => Some(Self::UnpauseCanisterMigrations),
             "NNS_FUNCTION_SET_SUBNET_OPERATIONAL_LEVEL" => Some(Self::SetSubnetOperationalLevel),
+            "NNS_FUNCTION_TAKE_CANISTER_SNAPSHOT" => Some(Self::TakeCanisterSnapshot),
             _ => None,
         }
     }

rs/nns/governance/proto/ic_nns_governance/pb/v1/governance.proto

@@ -495,6 +495,9 @@ enum NnsFunction {
 
   // Take subnet offline or bring back online. Used as part of subnet recovery.
   NNS_FUNCTION_SET_SUBNET_OPERATIONAL_LEVEL = 55;
+
+  // Take a canister snapshot.
+  NNS_FUNCTION_TAKE_CANISTER_SNAPSHOT = 56;
 }
 
 // Payload of a proposal that calls a function on another NNS

rs/nns/governance/src/canister_state.rs

@@ -394,7 +394,8 @@ fn get_effective_payload(
         | ValidNnsFunction::DeployHostosToSomeNodes
         | ValidNnsFunction::PauseCanisterMigrations
         | ValidNnsFunction::UnpauseCanisterMigrations
-        | ValidNnsFunction::SetSubnetOperationalLevel => Ok(payload.clone()),
+        | ValidNnsFunction::SetSubnetOperationalLevel
+        | ValidNnsFunction::TakeCanisterSnapshot => Ok(payload.clone()),
     }
 }
 

rs/nns/governance/src/gen/ic_nns_governance.pb.v1.rs

@@ -4820,6 +4820,8 @@ pub enum NnsFunction {
     UnpauseCanisterMigrations = 54,
     /// Take subnet offline or bring back online. Used as part of subnet recovery.
     SetSubnetOperationalLevel = 55,
+    /// Take a canister snapshot.
+    TakeCanisterSnapshot = 56,
 }
 impl NnsFunction {
     /// String value of the enum field names used in the ProtoBuf definition.
@@ -4893,6 +4895,7 @@ impl NnsFunction {
             Self::PauseCanisterMigrations => "NNS_FUNCTION_PAUSE_CANISTER_MIGRATIONS",
             Self::UnpauseCanisterMigrations => "NNS_FUNCTION_UNPAUSE_CANISTER_MIGRATIONS",
             Self::SetSubnetOperationalLevel => "NNS_FUNCTION_SET_SUBNET_OPERATIONAL_LEVEL",
+            Self::TakeCanisterSnapshot => "NNS_FUNCTION_TAKE_CANISTER_SNAPSHOT",
         }
     }
     /// Creates an enum from field names used in the ProtoBuf definition.
@@ -4973,6 +4976,7 @@ impl NnsFunction {
             "NNS_FUNCTION_PAUSE_CANISTER_MIGRATIONS" => Some(Self::PauseCanisterMigrations),
             "NNS_FUNCTION_UNPAUSE_CANISTER_MIGRATIONS" => Some(Self::UnpauseCanisterMigrations),
             "NNS_FUNCTION_SET_SUBNET_OPERATIONAL_LEVEL" => Some(Self::SetSubnetOperationalLevel),
+            "NNS_FUNCTION_TAKE_CANISTER_SNAPSHOT" => Some(Self::TakeCanisterSnapshot),
             _ => None,
         }
     }

rs/nns/governance/src/governance.rs

@@ -1,6 +1,7 @@
 #![allow(deprecated)]
 use crate::{
-    are_nf_fund_proposals_disabled, are_performance_based_rewards_enabled, decoder_config,
+    are_canister_snapshot_proposals_enabled, are_nf_fund_proposals_disabled,
+    are_performance_based_rewards_enabled, decoder_config,
     governance::{
         merge_neurons::{
             build_merge_neurons_response, calculate_merge_neurons_effect,
@@ -4807,6 +4808,13 @@ impl Governance {
                 Self::validate_add_or_remove_data_centers_payload(&update.payload)
                     .map_err(invalid_proposal_error)?;
             }
+            ValidNnsFunction::TakeCanisterSnapshot => {
+                if !are_canister_snapshot_proposals_enabled() {
+                    return Err(invalid_proposal_error(
+                        "TakeCanisterSnapshot proposals are not yet enabled.".to_string(),
+                    ));
+                }
+            }
             _ => {}
         };
 

rs/nns/governance/src/pb/conversions/mod.rs

@@ -3987,6 +3987,7 @@ impl From<pb::NnsFunction> for pb_api::NnsFunction {
             pb::NnsFunction::SetSubnetOperationalLevel => {
                 pb_api::NnsFunction::SetSubnetOperationalLevel
             }
+            pb::NnsFunction::TakeCanisterSnapshot => pb_api::NnsFunction::TakeCanisterSnapshot,
         }
     }
 }
@@ -4096,6 +4097,7 @@ impl From<pb_api::NnsFunction> for pb::NnsFunction {
             pb_api::NnsFunction::SetSubnetOperationalLevel => {
                 pb::NnsFunction::SetSubnetOperationalLevel
             }
+            pb_api::NnsFunction::TakeCanisterSnapshot => pb::NnsFunction::TakeCanisterSnapshot,
         }
     }
 }

rs/nns/governance/src/proposals/execute_nns_function.rs

@@ -153,6 +153,7 @@ pub enum ValidNnsFunction {
     PauseCanisterMigrations,
     UnpauseCanisterMigrations,
     SetSubnetOperationalLevel,
+    TakeCanisterSnapshot,
 }
 
 impl ValidNnsFunction {
@@ -281,6 +282,7 @@ impl ValidNnsFunction {
             ValidNnsFunction::SetSubnetOperationalLevel => {
                 (REGISTRY_CANISTER_ID, "set_subnet_operational_level")
             }
+            ValidNnsFunction::TakeCanisterSnapshot => (ROOT_CANISTER_ID, "take_canister_snapshot"),
         }
     }
 
@@ -341,6 +343,8 @@ impl ValidNnsFunction {
             ValidNnsFunction::AddSnsWasm | ValidNnsFunction::InsertSnsWasmUpgradePathEntries => {
                 Topic::ServiceNervousSystemManagement
             }
+
+            ValidNnsFunction::TakeCanisterSnapshot => Topic::ProtocolCanisterManagement,
         }
     }
 
@@ -397,6 +401,7 @@ impl ValidNnsFunction {
             ValidNnsFunction::PauseCanisterMigrations => "Pause Canister Migrations",
             ValidNnsFunction::UnpauseCanisterMigrations => "Unpause Canister Migrations",
             ValidNnsFunction::SetSubnetOperationalLevel => "Set Subnet Operational Level",
+            ValidNnsFunction::TakeCanisterSnapshot => "Take Canister Snapshot",
         }
     }
 
@@ -623,6 +628,11 @@ impl ValidNnsFunction {
                 used to take a subnet offline or bring it back online as part of \
                 subnet recovery."
             }
+            ValidNnsFunction::TakeCanisterSnapshot => {
+                "A proposal to take a snapshot of a canister controlled the NNS. \
+                 For an introduction to canister snapshots in general, see \
+                 https://docs.internetcomputer.org/building-apps/canister-management/snapshots ."
+            }
         }
     }
 }
@@ -711,6 +721,7 @@ impl TryFrom<NnsFunction> for ValidNnsFunction {
             NnsFunction::SetSubnetOperationalLevel => {
                 Ok(ValidNnsFunction::SetSubnetOperationalLevel)
             }
+            NnsFunction::TakeCanisterSnapshot => Ok(ValidNnsFunction::TakeCanisterSnapshot),
 
             // Obsolete functions - based on check_obsolete
             NnsFunction::BlessReplicaVersion | NnsFunction::RetireReplicaVersion => {

rs/nns/governance/unreleased_changelog.md

@@ -9,6 +9,10 @@ on the process that this file is part of, see
 
 ## Added
 
+* New TakeCanisterSnapshot proposal type. Disabled for now, but will be enabled
+  in the not too distant future. For now, the declarations are in place (in
+  governance.did), which helps clients to get ready for this new proposal type.
+
 ## Changed
 
 ## Deprecated