fix(epoch_sync) - fix unintential epoch sync feature inclusion (#11158)

The epoch sync was getting enabled when using wide build commands that
included the epoch sync tool.

I'm moving the conditional enablement from Cargo.toml to the rust files.

Additional information:
https://near.zulipchat.com/#narrow/stream/300659-Rust-.F0.9F.A6.80/topic/PSA.3A.20don't.20use.20.60cargo.20build.20--bin.20neard.60

neard/Cargo.toml

@@ -74,7 +74,7 @@ rosetta_rpc = ["nearcore/rosetta_rpc"]
 json_rpc = ["nearcore/json_rpc"]
 protocol_feature_fix_staking_threshold = ["nearcore/protocol_feature_fix_staking_threshold"]
 protocol_feature_nonrefundable_transfer_nep491 = ["near-state-viewer/protocol_feature_nonrefundable_transfer_nep491"]
-new_epoch_sync = ["nearcore/new_epoch_sync", "dep:near-epoch-sync-tool"]
+new_epoch_sync = ["nearcore/new_epoch_sync", "near-epoch-sync-tool/new_epoch_sync"]
 yield_resume = ["nearcore/yield_resume"]
 
 nightly = [

tools/epoch-sync/Cargo.toml

@@ -11,14 +11,34 @@ publish = false
 [lints]
 workspace = true
 
+# The dependencies are marked optional because we only need them when the
+# new_epoch_sync feature is enabled.
 [dependencies]
-anyhow.workspace = true
-clap.workspace = true
-tracing.workspace = true
+anyhow = { workspace = true, optional = true }
+clap = { workspace = true, optional = true }
+tracing = { workspace = true, optional = true }
 
-nearcore = { workspace = true, features = ["new_epoch_sync"] }
-near-chain.workspace = true
-near-chain-configs.workspace = true
-near-epoch-manager.workspace = true
-near-primitives.workspace = true
-near-store.workspace = true
+nearcore = { workspace = true, optional = true }
+near-chain = { workspace = true, optional = true }
+near-chain-configs = { workspace = true, optional = true }
+near-epoch-manager = { workspace = true, optional = true }
+near-primitives = { workspace = true, optional = true }
+near-store = { workspace = true, optional = true }
+
+[features]
+
+default = []
+new_epoch_sync = [
+    "nearcore/new_epoch_sync",
+
+    "dep:anyhow",
+    "dep:clap",
+    "dep:tracing",
+
+    "dep:nearcore",
+    "dep:near-chain",
+    "dep:near-chain-configs",
+    "dep:near-epoch-manager",
+    "dep:near-primitives",
+    "dep:near-store",
+]

tools/epoch-sync/src/cli.rs

@@ -1,3 +1,5 @@
+#![cfg(feature = "new_epoch_sync")]
+
 use anyhow::Context;
 use clap;
 use near_chain::{ChainStore, ChainStoreAccess, ChainUpdate, DoomslugThresholdMode};

tools/epoch-sync/src/lib.rs

@@ -1,2 +1,4 @@
+#[cfg(feature = "new_epoch_sync")]
 pub mod cli;
+#[cfg(feature = "new_epoch_sync")]
 pub use cli::EpochSyncCommand;