Fix 'with-sqlite-transaction'

* lisp/sqlite.el (with-sqlite-transaction): Tuck misplaced body
of else form back into feature-test control structure whence it
escaped.  (Bug#67142)

* test/lisp/sqlite-tests.el: New file to accompany
test/src/sqlite-tests.el.

lisp/sqlite.el

@@ -32,7 +32,8 @@
 If BODY completes normally, commit the changes and return
 the value of BODY.
 If BODY signals an error, or transaction commit fails, roll
-back the transaction changes."
+back the transaction changes before allowing the signal to
+propagate."
   (declare (indent 1) (debug (form body)))
   (let ((db-var (gensym))
         (func-var (gensym))
@@ -48,8 +49,8 @@ back the transaction changes."
                  (setq ,res-var (funcall ,func-var))
                  (setq ,commit-var (sqlite-commit ,db-var))
                  ,res-var)
-             (or ,commit-var (sqlite-rollback ,db-var))))
+             (or ,commit-var (sqlite-rollback ,db-var)))
-         (funcall ,func-var))))
+         (funcall ,func-var)))))
 
 (provide 'sqlite)
 

test/lisp/sqlite-tests.el

@@ -0,0 +1,51 @@
+;;; sqlite-tests.el --- Tests for sqlite.el  -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2024 Free Software Foundation, Inc.
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;;; Code:
+(require 'sqlite)
+
+(ert-deftest with-sqlite-transaction ()
+  (skip-unless (sqlite-available-p))
+  (let ((db (sqlite-open)))
+    (sqlite-execute db "create table test (a)")
+    (should
+     (eql 42 (with-sqlite-transaction db
+               (sqlite-execute db "insert into test values (1)")
+               (should (equal '((1)) (sqlite-select db "select * from test")))
+               42)))
+    ;; Body runs exactly once.
+    (should (equal '((1)) (sqlite-select db "select * from test")))))
+
+(ert-deftest with-sqlite-transaction/rollback ()
+  (skip-unless (sqlite-available-p))
+  (let ((db (sqlite-open)))
+    (sqlite-execute db "create table test (a)")
+    (should (equal '(sqlite-error
+                     ("SQL logic error" "no such function: fake" 1 1))
+                   (should-error
+                    (with-sqlite-transaction db
+                      (sqlite-execute db "insert into test values (1)")
+                      (sqlite-execute db "insert into test values (fake(2))")
+                      42))))
+    ;; First insertion (a=1) rolled back.
+    (should-not (sqlite-select db "select * from test"))))
+
+;;; sqlite-tests.el ends here