Fix `moderncsqlite` errors and rebase onto `main` (#2832)

This is #2819 but rebased on latest `main`. This PR is against main too
as opposed to the `moderncsqlite` branch.

The main change here is simply:

```go
// add query parameters to the dsn
if strings.Contains(dsn, "?") {
	dsn += "&"
} else {
	dsn += "?"
}

// wait some time before erroring if the db is locked
// https://gitlab.com/cznic/sqlite/-/issues/106#note_1058094993
dsn += "_pragma=busy_timeout%3d10000"
```

### Pull Request Checklist

<!-- Please read
https://matrix-org.github.io/dendrite/development/contributing before
submitting your pull request -->

* [x] I have added tests for PR _or_ I have justified why this PR
doesn't need tests.
* [x] Pull request includes a [sign off below using a legally
identifiable
name](https://matrix-org.github.io/dendrite/development/contributing#sign-off)
_or_ I have already signed off privately

Signed off privately.

Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>

8 files changed, 102 insertions, 20 deletions

diff --git a/internal/sqlutil/migrate_test.go b/internal/sqlutil/migrate_test.go
index 5116237a..30aa6790 100644
--- a/internal/sqlutil/migrate_test.go
+++ b/internal/sqlutil/migrate_test.go
@@ -7,8 +7,6 @@ import (
 	"reflect"
 	"testing"
 
-	_ "github.com/mattn/go-sqlite3"
-
 	"github.com/matrix-org/dendrite/internal/sqlutil"
 	"github.com/matrix-org/dendrite/test"
 )
@@ -88,7 +86,7 @@ func Test_migrations_Up(t *testing.T) {
 
 		for _, tt := range tests {
 			t.Run(tt.name, func(t *testing.T) {
-				driverName := "sqlite3"
+				driverName := sqlutil.SQLITE_DRIVER_NAME
 				if dbType == test.DBTypePostgres {
 					driverName = "postgres"
 				}
@@ -117,7 +115,7 @@ func Test_insertMigration(t *testing.T) {
 	test.WithAllDatabases(t, func(t *testing.T, dbType test.DBType) {
 		conStr, close := test.PrepareDBConnectionString(t, dbType)
 		defer close()
-		driverName := "sqlite3"
+		driverName := sqlutil.SQLITE_DRIVER_NAME
 		if dbType == test.DBTypePostgres {
 			driverName = "postgres"
 		}
diff --git a/internal/sqlutil/sqlite_cgo.go b/internal/sqlutil/sqlite_cgo.go
new file mode 100644
index 00000000..efb743fc
--- /dev/null
+++ b/internal/sqlutil/sqlite_cgo.go
@@ -0,0 +1,19 @@
+//go:build cgo
+// +build cgo
+
+package sqlutil
+
+import (
+	"github.com/mattn/go-sqlite3"
+	_ "github.com/mattn/go-sqlite3"
+)
+
+const SQLITE_DRIVER_NAME = "sqlite3"
+
+func sqliteDSNExtension(dsn string) string {
+	return dsn
+}
+
+func sqliteDriver() *sqlite3.SQLiteDriver {
+	return &sqlite3.SQLiteDriver{}
+}
diff --git a/internal/sqlutil/sqlite_native.go b/internal/sqlutil/sqlite_native.go
new file mode 100644
index 00000000..ed500afc
--- /dev/null
+++ b/internal/sqlutil/sqlite_native.go
@@ -0,0 +1,29 @@
+//go:build !cgo
+// +build !cgo
+
+package sqlutil
+
+import (
+	"modernc.org/sqlite"
+	"strings"
+)
+
+const SQLITE_DRIVER_NAME = "sqlite"
+
+func sqliteDSNExtension(dsn string) string {
+	// add query parameters to the dsn
+	if strings.Contains(dsn, "?") {
+		dsn += "&"
+	} else {
+		dsn += "?"
+	}
+
+	// wait some time before erroring if the db is locked
+	// https://gitlab.com/cznic/sqlite/-/issues/106#note_1058094993
+	dsn += "_pragma=busy_timeout%3d10000"
+	return dsn
+}
+
+func sqliteDriver() *sqlite.Driver {
+	return &sqlite.Driver{}
+}
diff --git a/internal/sqlutil/sqlutil.go b/internal/sqlutil/sqlutil.go
index 789bceea..39a067e5 100644
--- a/internal/sqlutil/sqlutil.go
+++ b/internal/sqlutil/sqlutil.go
@@ -20,11 +20,12 @@ func Open(dbProperties *config.DatabaseOptions, writer Writer) (*sql.DB, error)
 	var driverName, dsn string
 	switch {
 	case dbProperties.ConnectionString.IsSQLite():
-		driverName = "sqlite3"
+		driverName = SQLITE_DRIVER_NAME
 		dsn, err = ParseFileURI(dbProperties.ConnectionString)
 		if err != nil {
 			return nil, fmt.Errorf("ParseFileURI: %w", err)
 		}
+		dsn = sqliteDSNExtension(dsn)
 	case dbProperties.ConnectionString.IsPostgres():
 		driverName = "postgres"
 		dsn = string(dbProperties.ConnectionString)
@@ -39,7 +40,7 @@ func Open(dbProperties *config.DatabaseOptions, writer Writer) (*sql.DB, error)
 	if err != nil {
 		return nil, err
 	}
-	if driverName != "sqlite3" {
+	if driverName != SQLITE_DRIVER_NAME {
 		logger := logrus.WithFields(logrus.Fields{
 			"max_open_conns":    dbProperties.MaxOpenConns(),
 			"max_idle_conns":    dbProperties.MaxIdleConns(),
diff --git a/internal/sqlutil/trace_driver.go b/internal/sqlutil/trace_driver.go
index b7bb3676..a2e0d12e 100644
--- a/internal/sqlutil/trace_driver.go
+++ b/internal/sqlutil/trace_driver.go
@@ -21,7 +21,6 @@ import (
 	"database/sql"
 
 	"github.com/lib/pq"
-	sqlite "github.com/mattn/go-sqlite3"
 	"github.com/ngrok/sqlmw"
 )
 
@@ -31,6 +30,6 @@ func registerDrivers() {
 	}
 	// install the wrapped drivers
 	sql.Register("postgres-trace", sqlmw.Driver(&pq.Driver{}, new(traceInterceptor)))
-	sql.Register("sqlite3-trace", sqlmw.Driver(&sqlite.SQLiteDriver{}, new(traceInterceptor)))
+	sql.Register("sqlite3-trace", sqlmw.Driver(sqliteDriver(), new(traceInterceptor)))
 
 }
diff --git a/internal/sqlutil/unique_constraint.go b/internal/sqlutil/unique_constraint.go
index ed70f5ed..767a586e 100644
--- a/internal/sqlutil/unique_constraint.go
+++ b/internal/sqlutil/unique_constraint.go
@@ -12,14 +12,15 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build !wasm
-// +build !wasm
+//go:build !wasm && !cgo
+// +build !wasm,!cgo
 
 package sqlutil
 
 import (
 	"github.com/lib/pq"
-	"github.com/mattn/go-sqlite3"
+	"modernc.org/sqlite"
+	lib "modernc.org/sqlite/lib"
 )
 
 // IsUniqueConstraintViolationErr returns true if the error is an unique_violation error
@@ -27,10 +28,8 @@ func IsUniqueConstraintViolationErr(err error) bool {
 	switch e := err.(type) {
 	case *pq.Error:
 		return e.Code == "23505"
-	case *sqlite3.Error:
-		return e.Code == sqlite3.ErrConstraint
-	case sqlite3.Error:
-		return e.Code == sqlite3.ErrConstraint
+	case *sqlite.Error:
+		return e.Code() == lib.SQLITE_CONSTRAINT
 	}
 	return false
 }
diff --git a/internal/sqlutil/unique_constraint_cgo.go b/internal/sqlutil/unique_constraint_cgo.go
new file mode 100644
index 00000000..edeb7c45
--- /dev/null
+++ b/internal/sqlutil/unique_constraint_cgo.go
@@ -0,0 +1,36 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build !wasm && cgo
+// +build !wasm,cgo
+
+package sqlutil
+
+import (
+	"github.com/lib/pq"
+	"github.com/mattn/go-sqlite3"
+)
+
+// IsUniqueConstraintViolationErr returns true if the error is an unique_violation error
+func IsUniqueConstraintViolationErr(err error) bool {
+	switch e := err.(type) {
+	case *pq.Error:
+		return e.Code == "23505"
+	case *sqlite3.Error:
+		return e.Code == sqlite3.ErrConstraint
+	case sqlite3.Error:
+		return e.Code == sqlite3.ErrConstraint
+	}
+	return false
+}
diff --git a/internal/sqlutil/unique_constraint_wasm.go b/internal/sqlutil/unique_constraint_wasm.go
index 02ceb585..ef393fa5 100644
--- a/internal/sqlutil/unique_constraint_wasm.go
+++ b/internal/sqlutil/unique_constraint_wasm.go
@@ -17,15 +17,16 @@
 
 package sqlutil
 
-import "github.com/mattn/go-sqlite3"
+import (
+	"modernc.org/sqlite"
+	lib "modernc.org/sqlite/lib"
+)
 
 // IsUniqueConstraintViolationErr returns true if the error is an unique_violation error
 func IsUniqueConstraintViolationErr(err error) bool {
 	switch e := err.(type) {
-	case *sqlite3.Error:
-		return e.Code == sqlite3.ErrConstraint
-	case sqlite3.Error:
-		return e.Code == sqlite3.ErrConstraint
+	case *sqlite.Error:
+		return e.Code() == lib.SQLITE_CONSTRAINT
 	}
 	return false
 }