[PATCH] ob-sqlite: Use a transient in-memory database by default

[Rudolf Adamkovič]

* etc/ORG-NEWS (New features): Add a news entry.
* lisp/ob-sqlite.el (org-babel-execute:sqlite): Default ':db' to ":memory:".
* testing/lisp/test-ob-sqlite.el (ob-sqlite/in-file): Test the old behavior.
* testing/lisp/test-ob-sqlite.el (ob-sqlite/in-memory): Test the new behavior.
---
 etc/ORG-NEWS                   |  6 ++++++
 lisp/ob-sqlite.el              |  3 +--
 testing/lisp/test-ob-sqlite.el | 36 ++++++++++++++++++++++++++++++++--
 3 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/etc/ORG-NEWS b/etc/ORG-NEWS
index 03894f128..42bfc2be0 100644
--- a/etc/ORG-NEWS
+++ b/etc/ORG-NEWS
@@ -181,6 +181,12 @@ official 
[[https://clojure.org/guides/deps_and_cli][Clojure CLI tools]].
 The command can be customized with ~ob-clojure-cli-command~.
 
 ** New features
+*** Make =ob-sqlite= use in-database by default
+
+SQLite source blocks with no =:db= argument now execute against a
+transient in-memory database.  This makes SQLite source blocks more
+practical, and it matches the default behavior of the =sqlite3= shell.
+
 *** Add support for ~logind~ idle time in ~org-user-idle-seconds~
 
 When Emacs is built with =dbus= support and
diff --git a/lisp/ob-sqlite.el b/lisp/ob-sqlite.el
index 526b73ebd..60da488f7 100644
--- a/lisp/ob-sqlite.el
+++ b/lisp/ob-sqlite.el
@@ -66,7 +66,7 @@
   "Execute a block of Sqlite code with Babel.
 This function is called by `org-babel-execute-src-block'."
   (let ((result-params (split-string (or (cdr (assq :results params)) "")))
-       (db (cdr (assq :db params)))
+       (db (or (cdr (assq :db params)) ":memory:"))
        (separator (cdr (assq :separator params)))
        (nullvalue (cdr (assq :nullvalue params)))
        (headers-p (equal "yes" (cdr (assq :colnames params))))
@@ -74,7 +74,6 @@ This function is called by `org-babel-execute-src-block'."
                           (lambda (arg) (car (assq arg params)))
                           (list :header :echo :bail :column
                                 :csv :html :line :list)))))
-    (unless db (error "ob-sqlite: can't evaluate without a database"))
     (with-temp-buffer
       (insert
        (org-babel-eval
diff --git a/testing/lisp/test-ob-sqlite.el b/testing/lisp/test-ob-sqlite.el
index 72d75c9b7..b76a82d98 100644
--- a/testing/lisp/test-ob-sqlite.el
+++ b/testing/lisp/test-ob-sqlite.el
@@ -39,8 +39,40 @@
   .import $tb TestTable
   select * from TestTable;
 #+end_src"
-           (org-babel-next-src-block)
-           (org-babel-execute-src-block)))))
+          (org-babel-next-src-block)
+          (org-babel-execute-src-block)))))
+
+(ert-deftest ob-sqlite/in-memory ()
+  "Test in-memory temporariness."
+  (should
+   (equal 0
+          (progn
+            (org-test-with-temp-text
+            "#+BEGIN_SRC sqlite
+PRAGMA user_version = 1;
+#+END_SRC"
+            (org-babel-execute-src-block))
+            (org-test-with-temp-text
+            "#+begin_src sqlite
+PRAGMA user_version;
+#+end_src"
+            (org-babel-execute-src-block))))))
+
+(ert-deftest ob-sqlite/in-file ()
+  "Test in-file permanency."
+  (should
+   (equal 1
+          (let ((file (org-babel-temp-file "test" ".sqlite")))
+            (org-test-with-temp-text
+            (format "#+BEGIN_SRC sqlite :db %s
+PRAGMA user_version = 1;
+#+END_SRC" file)
+            (org-babel-execute-src-block))
+            (org-test-with-temp-text
+            (format "#+BEGIN_SRC sqlite :db %s
+PRAGMA user_version;
+#+END_SRC" file)
+            (org-babel-execute-src-block))))))
 
 (provide 'test-ob-sqlite)
 ;;; test-ob-sqlite.el ends here
-- 
2.40.1