fix: handle signer db open errors cleanly

changelog.d/signer-db-open-error.fixed

@@ -0,0 +1 @@
+The signer now exits with an error naming the problem when it cannot open its database, for example one written by a newer release, instead of panicking.

stacks-signer/src/main.rs

@@ -44,6 +44,7 @@ use stacks_signer::cli::{
 };
 use stacks_signer::config::GlobalConfig;
 use stacks_signer::monitor_signers::SignerMonitor;
+use stacks_signer::signerdb::SignerDb;
 use stacks_signer::utils::stackerdb_session;
 use stacks_signer::v0::SpawnedSigner;
 use tracing_subscriber::prelude::*;
@@ -115,6 +116,15 @@ fn handle_put_chunk(args: PutChunkArgs) {
 fn handle_run(args: RunSignerArgs) {
     debug!("Running signer...");
     let config = GlobalConfig::try_from(&args.config).unwrap();
+    // Open (and migrate) the signer db before starting, so a db this release cannot use stops
+    // the signer with an error instead of a panic, possibly in a signer thread.
+    if let Err(e) = SignerDb::new(&config.db_path) {
+        error!(
+            "Failed to open the signer db at {}: {e}",
+            config.db_path.display()
+        );
+        std::process::exit(1);
+    }
     let spawned_signer = SpawnedSigner::new(config);
     println!("Signer spawned successfully. Waiting for messages to process...");
     // Wait for the spawned signer to stop (will only occur if an error occurs)

stacks-signer/src/signerdb.rs

@@ -1840,7 +1840,7 @@ impl SignerDb {
             std::cmp::Ordering::Greater => {
                 sql_tx.rollback()?;
                 return Err(DBError::Other(format!(
-                    "Database schema is newer than SCHEMA_VERSION. SCHEMA_VERSION = {}, Current version = {}. Did you forget to update SCHEMA_VERSION?",
+                    "Database schema is newer than SCHEMA_VERSION. SCHEMA_VERSION = {}, Current version = {}. The database was likely written by a newer signer release; downgrading is not supported. Run a newer release or use a different db_path.",
                     Self::SCHEMA_VERSION, current_db_version
                 )));
             }