Use MAX_BLOCK_REORG_HEIGHT in zebra-checkpoints

MAX_BLOCK_REORG_HEIGHT is 1 less than the constant it replaces. The new
calculation is correct: the 100th block is finalized.

Cargo.lock

@@ -3356,6 +3356,7 @@ dependencies = [
  "tracing-subscriber 0.2.14",
  "zebra-chain",
  "zebra-consensus",
+ "zebra-state",
 ]
 
 [[package]]

zebra-state/src/lib.rs

@@ -23,6 +23,7 @@ use service::QueuedBlock;
 use sled_state::FinalizedState;
 
 pub use config::Config;
+pub use constants::MAX_BLOCK_REORG_HEIGHT;
 pub use error::{BoxError, CloneError, CommitBlockError, ValidateContextError};
 pub use request::{HashOrHeight, Request};
 pub use response::Response;

zebra-utils/Cargo.toml

@@ -17,3 +17,4 @@ tracing-subscriber = { version = "0.2.14", features = ["tracing-log"] }
 
 zebra-chain = { path = "../zebra-chain" }
 zebra-consensus = { path = "../zebra-consensus" }
+zebra-state = { path = "../zebra-state" }

zebra-utils/src/bin/zebra-checkpoints/main.rs

@@ -30,10 +30,6 @@ mod args;
 /// constant factor of the serialized size.
 const MAX_CHECKPOINT_BYTE_COUNT: u64 = 256 * 1024 * 1024;
 
-/// Checkpoints must be on the main chain, so we skip blocks that are within the
-/// zcashd reorg limit.
-const BLOCK_REORG_LIMIT: block::Height = block::Height(100);
-
 /// Initialise tracing using its defaults.
 fn init_tracing() {
     tracing_subscriber::Registry::default()
@@ -89,9 +85,11 @@ fn main() -> Result<()> {
     // calculate the maximum height
     let height_limit: block::Height = cmd_output(&mut cmd)?.trim().parse()?;
     assert!(height_limit <= block::Height::MAX);
+    // Checkpoints must be on the main chain, so we skip blocks that are within the
+    // Zcash reorg limit.
     let height_limit = height_limit
         .0
-        .checked_sub(BLOCK_REORG_LIMIT.0)
+        .checked_sub(zebra_state::MAX_BLOCK_REORG_HEIGHT.0)
         .map(block::Height)
         .expect("zcashd has some mature blocks: wait for zcashd to sync more blocks");