refactor: stop using log memory store feature flag and migration fields in production

[mraszyk]

The one-time migration from the legacy CanisterLog store to the LogMemoryStore has completed on all subnets, so production code no longer needs to consult the feature flag or the per-canister migration status. This decouples the runtime logic from those fields while keeping them serialized for downgrade compatibility (unlike #10714, which was reverted).

• Drop the log_memory_store_feature flag from Config and all plumbing (canister manager config, SystemState::new*, LogMemoryStore::new(), fetch_canister_logs, scheduler). The LOG_MEMORY_STORE_FEATURE / _ENABLED consts are retained but now unused by production logic.
• Remove the migration scaffolding: the subnet-level logs_migrated metadata, the scheduler migration code (and filter_canister_log_records), the migration-duration metric, and the orphaned set_migrated / clear_migrated methods.
• Collapse all production is_migrated() branches to the always-migrated path. next_canister_log_record_idx and log_memory_store_migrated (proto 44/66) are still written and round-tripped, and the legacy canister_log store is retained and kept up to date via dual-write, so checkpoints remain readable by replicas that predate the log memory store.

[zeropath-ai]

✅ No security or compliance issues detected. Reviewed everything up to 8dccff3.

Security Overview

• 🔎 Scanned files: 25 changed file(s)
• 🔗 Scan Link: https://zeropath.com/app/repositories/f5e9d2bb-29a4-4b64-902a-391d65fd8b2d?scanId=7f547834-6d3c-49f2-bb3e-59ee2a95cc53&codeScanTypes=PrScan&tab=issues

Detected Code Changes

Change Type	Relevant files
Refactor	► rs/config/src/execution_environment.rs     Remove log_memory_store_feature field from Config and Default implementation
Enhancement	► rs/embedders/src/wasmtime_embedder/system_api/sandbox_safe_system_state.rs     Always append delta log to log memory store and adjust checkpoint readability note ► rs/embedders/src/wasmtime_embedder/system_api/sandbox_safe_system_state.rs     Simplify next index/memory limit calculation to use log_memory_store unconditionally
Refactor	► rs/embedders/src/wasmtime_embedder/tests.rs     Remove reliance on LOG_MEMORY_STORE_FEATURE in test setup
Refactor	► rs/execution_environment/benches/management_canister/canister_logging.rs     Remove LOG_MEMORY_STORE_FEATURE usage in bench config
Refactor	► rs/execution_environment/src/canister_logs.rs     Remove log_memory_store_feature parameter from fetch_canister_logs and related response construction
Refactor	► rs/execution_environment/src/canister_manager.rs     Remove log_memory_store_feature usage in canister creation flow and related config passing
Refactor	► rs/execution_environment/src/canister_manager/types.rs     Remove log_memory_store_feature field from CanisterMgrConfig
Refactor	► rs/execution_environment/src/execution_environment.rs     Remove log_memory_store_feature from call to create_isolation/exec environment setup
Refactor	► rs/execution_environment/src/lib.rs     Remove log_memory_store_feature from ExecutionServices setup
Refactor	► rs/execution_environment/src/query_handler.rs     Update fetch_canister_logs path to remove log_memory_store_feature parameter
Refactor	► rs/execution_environment/src/scheduler.rs     Remove log_memory_store_feature from Scheduler and related metrics/state plumbing
Refactor	► rs/execution_environment/src/scheduler/scheduler_metrics.rs     Remove round_log_memory_store_migration_duration metric
Refactor	► rs/execution_environment/src/scheduler/test_utilities.rs     Remove passing log_memory_store_feature in test builder
Refactor	► rs/execution_environment/tests/canister_logging.rs     Remove LOG_MEMORY_STORE_FEATURE usage in tests
Refactor	► rs/execution_environment/tests/canister_logging.rs     Remove test references to log memory store feature flag
Refactor	► rs/execution_environment/src/scheduler/test_utilities.rs     Remove log_memory_store_feature from test builder construction

[Copilot]

Pull request overview

This PR removes the now-obsolete log migration/runtime toggling logic by making LogMemoryStore the unconditional production source of truth, while still dual-writing and preserving serialized fields to keep checkpoints readable for older replicas.

Changes:

• Removes the log_memory_store_feature flag from ic_config::execution_environment::Config and deletes all runtime branching/plumbing based on it.
• Deletes migration scaffolding (logs_migrated subnet metadata, scheduler migration pass, migration metrics, and related helpers), collapsing logic to the “always migrated” path.
• Updates log fetch, metrics, tests, and benchmarks to use LogMemoryStore APIs unconditionally, while keeping legacy canister_log updated via dual-write for downgrade/checkpoint compatibility.

Reviewed changes

Copilot reviewed 25 out of 25 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
rs/test_utilities/execution_environment/src/lib.rs	Removes test builder helpers for toggling the log memory store feature flag.
rs/state_manager/src/checkpoint.rs	Always checks the next_idx soft invariant between log_memory_store and canister_log.
rs/replicated_state/src/metrics.rs	Records log memory usage/retention from LogMemoryStore unconditionally.
rs/replicated_state/src/metadata_state/proto.rs	Removes initialization of transient logs_migrated metadata.
rs/replicated_state/src/metadata_state.rs	Removes the logs_migrated transient field and associated struct plumbing.
rs/replicated_state/src/canister_state/system_state/log_memory_store/tests/log_memory_store.rs	Updates tests to the new LogMemoryStore::new() signature and removes flag-dependent cases.
rs/replicated_state/src/canister_state/system_state/log_memory_store/tests/canister_lifecycle.rs	Updates lifecycle test setup to use LogMemoryStore::new() without flags.
rs/replicated_state/src/canister_state/system_state/log_memory_store/mod.rs	Drops FlagStatus dependency, makes new() flag-free and “always migrated”, removes migrated mutators, adds Default.
rs/replicated_state/src/canister_state/system_state.rs	Removes feature-flag plumbing from SystemState construction; always constructs LogMemoryStore directly.
rs/replicated_state/benches/log_memory_store.rs	Updates benchmark setup to use LogMemoryStore::new() without feature flags.
rs/execution_environment/tests/canister_logging.rs	Removes feature-flag-specific integration tests and updates configs/callers accordingly.
rs/execution_environment/src/scheduler/test_utilities.rs	Removes passing log_memory_store_feature into scheduler construction.
rs/execution_environment/src/scheduler/scheduler_metrics.rs	Removes migration-duration metric from scheduler metrics.
rs/execution_environment/src/scheduler.rs	Removes per-round migration logic and the legacy-gap filtering helper + tests.
rs/execution_environment/src/query_handler.rs	Simplifies fetch-canister-logs query handling by removing flag parameter plumbing.
rs/execution_environment/src/lib.rs	Removes feature-flag plumbing when wiring execution services.
rs/execution_environment/src/execution_environment.rs	Updates the replicated management call path to use the new fetch_canister_logs signature.
rs/execution_environment/src/canister_manager/types.rs	Removes log_memory_store_feature from canister manager configuration.
rs/execution_environment/src/canister_manager/tests.rs	Updates tests to remove feature-flag configuration and builder usage.
rs/execution_environment/src/canister_manager.rs	Applies log memory limit logic unconditionally (no longer gated by migration status) and removes flag from system state creation.
rs/execution_environment/src/canister_logs.rs	Makes fetch-canister-logs responses always read from LogMemoryStore and removes legacy filtering path.
rs/execution_environment/benches/management_canister/canister_logging.rs	Removes feature-flag config usage in benchmarks.
rs/embedders/src/wasmtime_embedder/tests.rs	Updates testing constructors to remove LOG_MEMORY_STORE_FEATURE parameter plumbing.
rs/embedders/src/wasmtime_embedder/system_api/sandbox_safe_system_state.rs	Always appends deltas to LogMemoryStore and always derives status fields from it; clarifies dual-write intent for legacy store.
rs/config/src/execution_environment.rs	Removes log_memory_store_feature from execution environment config and its default initialization.

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