Fix OpenConn WAL handling (zombiezen#34)

Connection needs to be set to block on busy before WAL journal mode is set in case it hasn't already set by another connection.

Journal-mode statement needs to be finalized before closing connection on error.

Co-authored-by: Ross Light <[email protected]>

Author: anacrolix

CHANGELOG.md

@@ -51,6 +51,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   but report success.
 - `sqlitemigration` will no longer skip applying the repeatable migration
   if the final migration is empty.
+- `OpenConn` now sets a busy handler before enabling WAL
+  (thanks @anacrolix!).
 
 ## [0.8.0][] - 2021-11-07
 

sqlite.go

@@ -113,15 +113,21 @@ func OpenConn(path string, flags ...OpenFlags) (*Conn, error) {
 	}
 
 	if openFlags&OpenWAL != 0 {
+		// Set timeout for enabling WAL.
+		// See https://github.com/crawshaw/sqlite/pull/113 for details.
+		// TODO(maybe): Pass in Context to OpenConn?
+		c.SetBusyTimeout(10 * time.Second)
+
 		stmt, _, err := c.PrepareTransient("PRAGMA journal_mode=wal;")
 		if err != nil {
 			c.Close()
 			return nil, fmt.Errorf("sqlite: open %q: %w", path, err)
 		}
-		defer stmt.Finalize()
-		if _, err := stmt.Step(); err != nil {
+		_, err = stmt.Step()
+		stmt.Finalize()
+		if err != nil {
 			c.Close()
-			return nil, fmt.Errorf("sqlite: open %q: %w", path, err)
+			return nil, fmt.Errorf("sqlite: open %q: enable wal: %w", path, err)
 		}
 	}