feat(sqlite): Support emit_pointers_for_null_types (#3026)

Pointer fields work with both the popular github.com/mattn/go-sqlite3
driver and the pure-Go modernc.org/sqlite driver.

Author: benhoyt

docs/reference/config.md

@@ -156,7 +156,7 @@ The `gen` mapping supports the following keys:
 - `emit_methods_with_db_argument`:
   - If true, generated methods will accept a DBTX argument instead of storing a DBTX on the `*Queries` struct. Defaults to `false`.
 - `emit_pointers_for_null_types`:
-  - If true and `sql_package` is set to `pgx/v4` or `pgx/v5`, generated types for nullable columns are emitted as pointers (ie. `*string`) instead of `database/sql` null types (ie. `NullString`). Defaults to `false`.
+  - If true, generated types for nullable columns are emitted as pointers (ie. `*string`) instead of `database/sql` null types (ie. `NullString`). Currently only supported for PostgreSQL if `sql_package` is `pgx/v4` or `pgx/v5`, and for SQLite. Defaults to `false`.
 - `emit_enum_valid_method`:
   - If true, generate a Valid method on enum types,
     indicating whether a string is a valid enum value.

internal/codegen/golang/go_type.go

@@ -85,7 +85,7 @@ func goInnerType(req *plugin.GenerateRequest, options *opts.Options, col *plugin
 	case "postgresql":
 		return postgresType(req, options, col)
 	case "sqlite":
-		return sqliteType(req, col)
+		return sqliteType(req, options, col)
 	default:
 		return "interface{}"
 	}

internal/codegen/golang/sqlite_type.go

@@ -4,21 +4,26 @@ import (
 	"log"
 	"strings"
 
+	"github.com/sqlc-dev/sqlc/internal/codegen/golang/opts"
 	"github.com/sqlc-dev/sqlc/internal/codegen/sdk"
 	"github.com/sqlc-dev/sqlc/internal/debug"
 	"github.com/sqlc-dev/sqlc/internal/plugin"
 )
 
-func sqliteType(req *plugin.GenerateRequest, col *plugin.Column) string {
+func sqliteType(req *plugin.GenerateRequest, options *opts.Options, col *plugin.Column) string {
 	dt := strings.ToLower(sdk.DataType(col.Type))
 	notNull := col.NotNull || col.IsArray
+	emitPointersForNull := options.EmitPointersForNullTypes
 
 	switch dt {
 
 	case "int", "integer", "tinyint", "smallint", "mediumint", "bigint", "unsignedbigint", "int2", "int8":
 		if notNull {
 			return "int64"
 		}
+		if emitPointersForNull {
+			return "*int64"
+		}
 		return "sql.NullInt64"
 
 	case "blob":
@@ -28,18 +33,27 @@ func sqliteType(req *plugin.GenerateRequest, col *plugin.Column) string {
 		if notNull {
 			return "float64"
 		}
+		if emitPointersForNull {
+			return "*float64"
+		}
 		return "sql.NullFloat64"
 
 	case "boolean", "bool":
 		if notNull {
 			return "bool"
 		}
+		if emitPointersForNull {
+			return "*bool"
+		}
 		return "sql.NullBool"
 
 	case "date", "datetime", "timestamp":
 		if notNull {
 			return "time.Time"
 		}
+		if emitPointersForNull {
+			return "*time.Time"
+		}
 		return "sql.NullTime"
 
 	case "any":
@@ -60,12 +74,18 @@ func sqliteType(req *plugin.GenerateRequest, col *plugin.Column) string {
 		if notNull {
 			return "string"
 		}
+		if emitPointersForNull {
+			return "*string"
+		}
 		return "sql.NullString"
 
 	case strings.HasPrefix(dt, "decimal"), dt == "numeric":
 		if notNull {
 			return "float64"
 		}
+		if emitPointersForNull {
+			return "*float64"
+		}
 		return "sql.NullFloat64"
 
 	default:

internal/endtoend/testdata/emit_pointers_for_null_types/sqlite/go/db.go

@@ -0,0 +1 @@
+SELECT 1;

internal/endtoend/testdata/emit_pointers_for_null_types/sqlite/go/models.go

@@ -0,0 +1,18 @@
+
+CREATE TABLE dt_types (
+    a int,
+    b real,
+    c bool,
+    d date,
+    e text,
+    f numeric
+);
+
+CREATE TABLE dt_types_not_null (
+    a int NOT NULL,
+    b real NOT NULL,
+    c bool NOT NULL,
+    d date NOT NULL,
+    e text NOT NULL,
+    f numeric NOT NULL
+);

internal/endtoend/testdata/emit_pointers_for_null_types/sqlite/sql/query.sql

@@ -0,0 +1,13 @@
+{
+  "version": "1",
+  "packages": [
+    {
+      "path": "go",
+      "engine": "sqlite",
+      "name": "datatype",
+      "schema": "sql/",
+      "queries": "sql/",
+      "emit_pointers_for_null_types": true
+    }
+  ]
+}