fix: correct schema upgrade logic (and refactor)

Schema upgrades were buggy from 4->5 (the v5 would be skipped).  This
change also refactors the logic slightly so that future additions can
be clearer (no need to have if and else-if combinations).

Cargo.lock

@@ -286,6 +286,26 @@ dependencies = [
  "tracing-subscriber 0.3.15",
 ]
 
+[[package]]
+name = "const_format"
+version = "0.2.28"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "79f926bc2341a80e6bb5a16e18057c8c90ca3edbdeb9fa497bd0f82b1f4df4e6"
+dependencies = [
+ "const_format_proc_macros",
+]
+
+[[package]]
+name = "const_format_proc_macros"
+version = "0.2.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef196d5d972878a48da7decb7686eded338b4858fbabeed513d63a7c98b2b82d"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-xid",
+]
+
 [[package]]
 name = "core-foundation"
 version = "0.9.3"
@@ -1008,6 +1028,7 @@ dependencies = [
  "bitcoin_hashes",
  "config",
  "console-subscriber",
+ "const_format",
  "futures",
  "futures-util",
  "governor",
@@ -2216,6 +2237,12 @@ dependencies = [
  "tinyvec",
 ]
 
+[[package]]
+name = "unicode-xid"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f962df74c8c05a667b5ee8bcf162993134c104e96440b663c8daa176dc772d8c"
+
 [[package]]
 name = "url"
 version = "2.3.1"

Cargo.toml

@@ -31,6 +31,7 @@ hyper-tls = "0.5"
 http = { version = "0.2" }
 parse_duration = "2"
 rand = "0.8"
+const_format = "0.2.28"
 
 [dev-dependencies]
 anyhow = "1"

src/schema.rs

@@ -3,9 +3,11 @@ use crate::db::PooledConnection;
 use crate::error::Result;
 use crate::event::{single_char_tagname, Event};
 use crate::utils::is_lower_hex;
+use const_format::formatcp;
 use rusqlite::limits::Limit;
 use rusqlite::params;
 use rusqlite::Connection;
+use std::cmp::Ordering;
 use std::time::Instant;
 use tracing::{debug, error, info};
 
@@ -17,15 +19,19 @@ PRAGMA journal_size_limit=32768;
 pragma mmap_size = 536870912; -- 512MB of mmap
 "##;
 
+/// Latest database version
+pub const DB_VERSION: usize = 6;
+
 /// Schema definition
-const INIT_SQL: &str = r##"
+const INIT_SQL: &str = formatcp!(
+    r##"
 -- Database settings
 PRAGMA encoding = "UTF-8";
 PRAGMA journal_mode=WAL;
 PRAGMA main.synchronous=NORMAL;
 PRAGMA foreign_keys = ON;
 PRAGMA application_id = 1654008667;
-PRAGMA user_version = 6;
+PRAGMA user_version = {};
 
 -- Event Table
 CREATE TABLE IF NOT EXISTS event (
@@ -72,7 +78,9 @@ FOREIGN KEY(metadata_event) REFERENCES event(id) ON UPDATE CASCADE ON DELETE CAS
 );
 CREATE INDEX IF NOT EXISTS user_verification_name_index ON user_verification(name);
 CREATE INDEX IF NOT EXISTS user_verification_event_index ON user_verification(metadata_event);
-"##;
+"##,
+    DB_VERSION
+);
 
 /// Determine the current application database schema version.
 pub fn db_version(conn: &mut Connection) -> Result<usize> {
@@ -100,6 +108,9 @@ pub fn upgrade_db(conn: &mut PooledConnection) -> Result<()> {
         (conn.limit(Limit::SQLITE_LIMIT_SQL_LENGTH) as f64 / (1024 * 1024) as f64).floor()
     );
 
+    match curr_version.cmp(&DB_VERSION) {
+        // Database is new or not current
+        Ordering::Less => {
             // initialize from scratch
             if curr_version == 0 {
                 match conn.execute_batch(INIT_SQL) {
@@ -112,6 +123,7 @@ pub fn upgrade_db(conn: &mut PooledConnection) -> Result<()> {
                     }
                 }
             }
+
             if curr_version == 1 {
                 // only change is adding a hidden column to events.
                 let upgrade_sql = r##"
@@ -130,6 +142,7 @@ PRAGMA user_version = 2;
                     }
                 }
             }
+
             if curr_version == 2 {
                 // this version lacks the tag column
                 info!("database schema needs update from 2->3");
@@ -177,6 +190,7 @@ PRAGMA user_version = 3;
                 tx.commit()?;
                 info!("Upgrade complete");
             }
+
             if curr_version == 3 {
                 info!("database schema needs update from 3->4");
                 let upgrade_sql = r##"
@@ -224,7 +238,9 @@ PRAGMA user_version=5;
                         panic!("database could not be upgraded");
                     }
                 }
-    } else if curr_version == 5 {
+            }
+
+            if curr_version == 5 {
                 info!("database schema needs update from 5->6");
                 // We need to rebuild the tags table.  iterate through the
                 // event table.  build event from json, insert tags into a
@@ -275,14 +291,20 @@ PRAGMA user_version=5;
                 let start = Instant::now();
                 conn.execute("VACUUM;", [])?;
                 info!("vacuumed DB after tags rebuild in {:?}", start.elapsed());
-    } else if curr_version == 6 {
-        debug!("Database version was already current (v6)");
-    } else if curr_version > 6 {
+            }
+        }
+        // Database is current, all is good
+        Ordering::Equal => {
+            debug!("Database version was already current (v{})", DB_VERSION);
+        }
+        // Database is newer than what this code understands, abort
+        Ordering::Greater => {
             panic!(
-            "Database version is newer than supported by this executable (v{})",
-            curr_version
+                "Database version is newer than supported by this executable (v{} > v{})",
+                curr_version, DB_VERSION
             );
         }
+    }
 
     // Setup PRAGMA
     conn.execute_batch(STARTUP_SQL)?;