Merge branch 'jason/NNS1-2935-6' into 'master'

refactor(nns): NNS1-2935 Refactor Neuron methods related to dissolve state and age into methods on the enum

The main goal is to make the Neuron type have a dissolve_state_and_age member, instead of dissolve_state and aging_since_timestamp_seconds. Therefore the methods that mostly operate on the existing 2 fields are refactored into methods on the dissolve_state_and_age enum. In the next MRs, more methods will be moved in a similar way, and after no Neuron methods directly use the existing 2 fields, those 2 fields can be replaced by a single member dissolve_state_and_age easily.

Other notes:

1. Some "deprecated\_..." methods are introduced to provide a temporary way of operating directly on those 2 fields, which will be no longer needed once https://gitlab.com/dfinity-lab/public/ic/-/merge_requests/18705 is merged.
2. The logic in increase_dissolve_delay is pretty complicated. Other than the tests added in this MR, the existing tests (in neuron/mod.rs) also helps make sure there is no regression. The new tests (against DissolveStateAndAge) are added based on the existing tests, and the existing tests will be deleted in the next MR. They are not deleted in this MR so that we can be more certain that the refactoring still pass those tests. 

See merge request dfinity-lab/public/ic!18732

rs/nns/governance/src/governance.rs

@@ -13,7 +13,7 @@ use crate::{
         reassemble_governance_proto, split_governance_proto, HeapGovernanceData, XdrConversionRate,
     },
     migrations::maybe_run_migrations,
-    neuron::types::{DissolveStateAndAge, Neuron, NeuronBuilder},
+    neuron::{DissolveStateAndAge, Neuron, NeuronBuilder},
     neuron_data_validation::{NeuronDataValidationSummary, NeuronDataValidator},
     neuron_store::{NeuronMetrics, NeuronStore},
     neurons_fund::{

rs/nns/governance/src/governance/ledger_helper.rs

@@ -1,6 +1,6 @@
 use crate::{
     governance::{governance_minting_account, neuron_subaccount},
-    neuron::types::Neuron,
+    neuron::Neuron,
     neuron_store::NeuronStore,
     pb::v1::{governance_error::ErrorType, GovernanceError},
 };

rs/nns/governance/src/governance/manage_neuron_request/neuron_mutation/merge_neuron_mutation.rs

@@ -93,7 +93,7 @@ impl GovernanceNeuronMutation for MergeNeuronMutation {
 
         let new_aging_since_timestamp_seconds = now.saturating_sub(new_age_seconds);
         let aging_timestamp_seconds_delta = (new_aging_since_timestamp_seconds as i128)
-            .saturating_sub(target_neuron.aging_since_timestamp_seconds as i128);
+            .saturating_sub(target_neuron.deprecated_aging_since_timestamp_seconds() as i128);
 
         Ok(btreemap! {
         source_neuron.id() => NeuronDeltas {
@@ -106,7 +106,7 @@ impl GovernanceNeuronMutation for MergeNeuronMutation {
                 .neg(),
             // Reset aging
             aging_since_timestamp_seconds: if source_stake_less_transaction_fee_e8s > 0 {
-                now.saturating_sub(source_neuron.aging_since_timestamp_seconds) as i128
+                now.saturating_sub(source_neuron.deprecated_aging_since_timestamp_seconds()) as i128
             } else {
                 0
             },
@@ -212,12 +212,13 @@ impl GovernanceNeuronMutation for MergeNeuronMutation {
                 // here, since we do not change the dissolve state in any other
                 // way.
                 // let source_age_timestamp_seconds = source_neuron_mut.aging_since_timestamp_seconds;
-                if source_neuron_mut.aging_since_timestamp_seconds != u64::MAX {
-                    source_neuron_mut.aging_since_timestamp_seconds =
+                if source_neuron_mut.deprecated_aging_since_timestamp_seconds() != u64::MAX {
+                    source_neuron_mut.deprecated_set_aging_since_timestamp_seconds(
                         saturating_add_or_subtract_u64_i128(
-                            source_neuron_mut.aging_since_timestamp_seconds,
+                            source_neuron_mut.deprecated_aging_since_timestamp_seconds(),
                             source_delta_mut.aging_since_timestamp_seconds,
-                        );
+                        ),
+                    );
                     // Record that the delta was partially applied
                     source_delta_mut.aging_since_timestamp_seconds = 0;
                 }
@@ -241,11 +242,12 @@ impl GovernanceNeuronMutation for MergeNeuronMutation {
                                 source_neuron_mut.cached_neuron_stake_e8s,
                                 original_delta_cached_neuron_stake_e8s.saturating_neg(),
                             );
-                        source_neuron_mut.aging_since_timestamp_seconds =
+                        source_neuron_mut.deprecated_set_aging_since_timestamp_seconds(
                             saturating_add_or_subtract_u64_i128(
-                                source_neuron_mut.aging_since_timestamp_seconds,
+                                source_neuron_mut.deprecated_aging_since_timestamp_seconds(),
                                 original_delta_aging_since_timestamp_seconds.saturating_neg(),
-                            );
+                            ),
+                        );
                     })
                     .expect("Expected the source neuron to exist");
 

rs/nns/governance/src/governance/manage_neuron_request/neuron_mutation/mod.rs

@@ -1,4 +1,4 @@
-use crate::{governance::Governance, neuron::types::Neuron, pb::v1::GovernanceError};
+use crate::{governance::Governance, neuron::Neuron, pb::v1::GovernanceError};
 use async_trait::async_trait;
 use ic_nns_common::pb::v1::NeuronId;
 use std::{
@@ -236,10 +236,10 @@ impl NeuronDeltas {
             neuron.staked_maturity_e8s_equivalent = Some(staked_maturity_e8s_equivalent_new_value);
         }
 
-        neuron.aging_since_timestamp_seconds = saturating_add_or_subtract_u64_i128(
-            neuron.aging_since_timestamp_seconds,
+        neuron.deprecated_set_aging_since_timestamp_seconds(saturating_add_or_subtract_u64_i128(
+            neuron.deprecated_aging_since_timestamp_seconds(),
             self.aging_since_timestamp_seconds,
-        );
+        ));
     }
 }
 

rs/nns/governance/src/governance/merge_neurons.rs

@@ -3,7 +3,7 @@ use crate::{
         combine_aged_stakes,
         ledger_helper::{BurnNeuronFeesOperation, NeuronStakeTransferOperation},
     },
-    neuron::types::{DissolveStateAndAge, Neuron},
+    neuron::{DissolveStateAndAge, Neuron},
     neuron_store::NeuronStore,
     pb::v1::{
         governance_error::ErrorType, manage_neuron::Merge, manage_neuron::NeuronIdOrSubaccount,
@@ -68,15 +68,15 @@ impl MergeNeuronsEffect {
 
     pub fn source_effect(&self) -> MergeNeuronsSourceEffect {
         MergeNeuronsSourceEffect {
-            dissolve_state_and_age: self.source_neuron_dissolve_state_and_age.clone(),
+            dissolve_state_and_age: self.source_neuron_dissolve_state_and_age,
             subtract_maturity: self.transfer_maturity_e8s,
             subtract_staked_maturity: self.transfer_staked_maturity_e8s,
         }
     }
 
     pub fn target_effect(&self) -> MergeNeuronsTargetEffect {
         MergeNeuronsTargetEffect {
-            dissolve_state_and_age: self.target_neuron_dissolve_state_and_age.clone(),
+            dissolve_state_and_age: self.target_neuron_dissolve_state_and_age,
             add_maturity: self.transfer_maturity_e8s,
             add_staked_maturity: self.transfer_staked_maturity_e8s,
         }
@@ -620,7 +620,7 @@ fn is_neuron_involved_with_open_proposals(
 mod tests {
     use super::*;
     use crate::{
-        neuron::types::{DissolveStateAndAge, NeuronBuilder},
+        neuron::{DissolveStateAndAge, NeuronBuilder},
         pb::v1::{neuron::Followees, proposal::Action, ManageNeuron, NeuronType, Proposal, Topic},
     };
     use assert_matches::assert_matches;

rs/nns/governance/src/governance/tests/mod.rs

@@ -1,6 +1,6 @@
 use super::*;
 use crate::{
-    neuron::types::{DissolveStateAndAge, NeuronBuilder},
+    neuron::{DissolveStateAndAge, NeuronBuilder},
     pb::v1::{
         governance::{followers_map::Followers, FollowersMap},
         Neuron as NeuronProto,
@@ -887,7 +887,7 @@ mod metrics_tests {
 }
 
 mod neuron_archiving_tests {
-    use crate::neuron::types::{DissolveStateAndAge, NeuronBuilder};
+    use crate::neuron::{DissolveStateAndAge, NeuronBuilder};
     use ic_base_types::PrincipalId;
     use ic_nns_common::pb::v1::NeuronId;
     use icp_ledger::Subaccount;
@@ -1040,7 +1040,7 @@ mod neuron_archiving_tests {
 mod cast_vote_and_cascade_follow {
     use crate::{
         governance::{Governance, MIN_DISSOLVE_DELAY_FOR_VOTE_ELIGIBILITY_SECONDS},
-        neuron::types::{DissolveStateAndAge, Neuron, NeuronBuilder},
+        neuron::{DissolveStateAndAge, Neuron, NeuronBuilder},
         neuron_store::NeuronStore,
         pb::v1::{neuron::Followees, Ballot, Topic, Vote},
     };