kvdb/sqlbase: use positive+negative build tags for new sql error parsing

In this commit, we use exhaustive build tags to ensure that we can
always build the `sqlbase` package, independent of the set build tags.
To do this, we move the type declarations _into_ the parsing functions.
This then allows us to create two versions for each db: with the db, and
without it.

To avoid a module tag round trip to get this working, we use a local
replace for now. Once this is merged in, we can do the tag (along side
rc3), then remove the replace.

kvdb/sqlbase/sqlerrors.go

@@ -1,15 +1,8 @@
-//go:build kvdb_postgres || (kvdb_sqlite && !(windows && (arm || 386)) && !(linux && (ppc64 || mips || mipsle || mips64)))
-
 package sqlbase
 
 import (
 	"errors"
 	"fmt"
-
-	"github.com/jackc/pgconn"
-	"github.com/jackc/pgerrcode"
-	"modernc.org/sqlite"
-	sqlite3 "modernc.org/sqlite/lib"
 )
 
 var (
@@ -22,15 +15,13 @@ var (
 // error.
 func MapSQLError(err error) error {
 	// Attempt to interpret the error as a sqlite error.
-	var sqliteErr *sqlite.Error
-	if errors.As(err, &sqliteErr) {
-		return parseSqliteError(sqliteErr)
+	if sqliteErr := parseSqliteError(err); sqliteErr != nil {
+		return sqliteErr
 	}
 
 	// Attempt to interpret the error as a postgres error.
-	var pqErr *pgconn.PgError
-	if errors.As(err, &pqErr) {
-		return parsePostgresError(pqErr)
+	if postgresErr := parsePostgresError(err); postgresErr != nil {
+		return postgresErr
 	}
 
 	// Return original error if it could not be classified as a database
@@ -38,48 +29,6 @@ func MapSQLError(err error) error {
 	return err
 }
 
-// parsePostgresError attempts to parse a sqlite error as a database agnostic
-// SQL error.
-func parseSqliteError(sqliteErr *sqlite.Error) error {
-	switch sqliteErr.Code() {
-	// Handle unique constraint violation error.
-	case sqlite3.SQLITE_CONSTRAINT_UNIQUE:
-		return &ErrSQLUniqueConstraintViolation{
-			DBError: sqliteErr,
-		}
-
-	// Database is currently busy, so we'll need to try again.
-	case sqlite3.SQLITE_BUSY:
-		return &ErrSerializationError{
-			DBError: sqliteErr,
-		}
-
-	default:
-		return fmt.Errorf("unknown sqlite error: %w", sqliteErr)
-	}
-}
-
-// parsePostgresError attempts to parse a postgres error as a database agnostic
-// SQL error.
-func parsePostgresError(pqErr *pgconn.PgError) error {
-	switch pqErr.Code {
-	// Handle unique constraint violation error.
-	case pgerrcode.UniqueViolation:
-		return &ErrSQLUniqueConstraintViolation{
-			DBError: pqErr,
-		}
-
-	// Unable to serialize the transaction, so we'll need to try again.
-	case pgerrcode.SerializationFailure:
-		return &ErrSerializationError{
-			DBError: pqErr,
-		}
-
-	default:
-		return fmt.Errorf("unknown postgres error: %w", pqErr)
-	}
-}
-
 // ErrSQLUniqueConstraintViolation is an error type which represents a database
 // agnostic SQL unique constraint violation.
 type ErrSQLUniqueConstraintViolation struct {

kvdb/sqlbase/sqlerrors_no_postgres.go

@@ -0,0 +1,9 @@
+//go:build !kvdb_postgres
+
+package sqlbase
+
+// parsePostgresError attempts to parse a postgres error as a database agnostic
+// SQL error.
+func parsePostgresError(err error) error {
+	return nil
+}

kvdb/sqlbase/sqlerrors_no_sqlite.go

@@ -0,0 +1,9 @@
+//go:build !kvdb_sqlite || (windows && (arm || 386)) || (linux && (ppc64 || mips || mipsle || mips64))
+
+package sqlbase
+
+// parseSqliteError attempts to parse a sqlite error as a database agnostic
+// SQL error.
+func parseSqliteError(err error) error {
+	return nil
+}

kvdb/sqlbase/sqlerrors_postgres.go

@@ -0,0 +1,37 @@
+//go:build kvdb_postgres
+
+package sqlbase
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/jackc/pgconn"
+	"github.com/jackc/pgerrcode"
+)
+
+// parsePostgresError attempts to parse a postgres error as a database agnostic
+// SQL error.
+func parsePostgresError(err error) error {
+	var pqErr *pgconn.PgError
+	if !errors.As(err, &pqErr) {
+		return nil
+	}
+
+	switch pqErr.Code {
+	// Handle unique constraint violation error.
+	case pgerrcode.UniqueViolation:
+		return &ErrSQLUniqueConstraintViolation{
+			DBError: pqErr,
+		}
+
+	// Unable to serialize the transaction, so we'll need to try again.
+	case pgerrcode.SerializationFailure:
+		return &ErrSerializationError{
+			DBError: pqErr,
+		}
+
+	default:
+		return fmt.Errorf("unknown postgres error: %w", pqErr)
+	}
+}

kvdb/sqlbase/sqlerrors_sqlite.go

@@ -0,0 +1,37 @@
+//go:build kvdb_sqlite && !(windows && (arm || 386)) && !(linux && (ppc64 || mips || mipsle || mips64))
+
+package sqlbase
+
+import (
+	"errors"
+	"fmt"
+
+	"modernc.org/sqlite"
+	sqlite3 "modernc.org/sqlite/lib"
+)
+
+// parseSqliteError attempts to parse a sqlite error as a database agnostic
+// SQL error.
+func parseSqliteError(err error) error {
+	var sqliteErr *sqlite.Error
+	if !errors.As(err, &sqliteErr) {
+		return nil
+	}
+
+	switch sqliteErr.Code() {
+	// Handle unique constraint violation error.
+	case sqlite3.SQLITE_CONSTRAINT_UNIQUE:
+		return &ErrSQLUniqueConstraintViolation{
+			DBError: sqliteErr,
+		}
+
+	// Database is currently busy, so we'll need to try again.
+	case sqlite3.SQLITE_BUSY:
+		return &ErrSerializationError{
+			DBError: sqliteErr,
+		}
+
+	default:
+		return fmt.Errorf("unknown sqlite error: %w", sqliteErr)
+	}
+}