Eliminate allocation in *Stmt.ColumnName

Fixes #118

Author: zombiezen

CHANGELOG.md

@@ -7,6 +7,19 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 [Unreleased]: https://github.com/zombiezen/go-sqlite/compare/v1.4.0...main
 
+## [Unreleased][]
+
+### Changed
+
+- The minimum `modernc.org/sqlite` version updated to 1.36.1.
+
+### Fixed
+
+- `*Stmt.ColumnName` no longer performs an allocation
+  ([#101](https://github.com/zombiezen/go-sqlite/issues/118)).
+- The doc comment for `OpenFlags` has been rewritten for clarity
+  ([#114](https://github.com/zombiezen/go-sqlite/pull/114)).
+
 ## [1.4.0][] - 2024-09-23
 
 Version 1.4 adds the `sqlitex.ResultBytes` function

sqlite.go

@@ -869,7 +869,12 @@ func (stmt *Stmt) ColumnCount() int {
 //
 // https://sqlite.org/c3ref/column_name.html
 func (stmt *Stmt) ColumnName(col int) string {
-	return libc.GoString(lib.Xsqlite3_column_name(stmt.conn.tls, stmt.stmt, int32(col)))
+	for name, namedCol := range stmt.colNames {
+		if namedCol == col {
+			return name
+		}
+	}
+	return ""
 }
 
 // BindParamCount reports the number of parameters in stmt.