gh-93925: Improve clarity of sqlite3 commit/rollback, and close docs (GH-93926)

Co-authored-by: CAM Gerlach <CAM.Gerlach@Gerlach.CAM>
(cherry picked from commit 6446592c89)

Co-authored-by: Erlend Egeberg Aasland <erlend.aasland@innova.no>

Doc/library/sqlite3.rst

@@ -413,21 +413,20 @@ Connection Objects
 
    .. method:: commit()
 
-      This method commits the current transaction. If you don't call this method,
+      Commit any pending transaction to the database.
-      anything you did since the last call to ``commit()`` is not visible from
+      If there is no open transaction, this method is a no-op.
-      other database connections. If you wonder why you don't see the data you've
-      written to the database, please check you didn't forget to call this method.
 
    .. method:: rollback()
 
-      This method rolls back any changes to the database since the last call to
+      Roll back to the start of any pending transaction.
-      :meth:`commit`.
+      If there is no open transaction, this method is a no-op.
 
    .. method:: close()
 
-      This closes the database connection. Note that this does not automatically
+      Close the database connection.
-      call :meth:`commit`. If you just close your database connection without
+      Any pending transaction is not committed implicitly;
-      calling :meth:`commit` first, your changes will be lost!
+      make sure to :meth:`commit` before closing
+      to avoid losing pending changes.
 
    .. method:: execute(sql[, parameters])
 

Modules/_sqlite/clinic/connection.c.h

@@ -248,7 +248,9 @@ PyDoc_STRVAR(pysqlite_connection_close__doc__,
 "close($self, /)\n"
 "--\n"
 "\n"
-"Closes the connection.");
+"Close the database connection.\n"
+"\n"
+"Any pending transaction is not committed implicitly.");
 
 #define PYSQLITE_CONNECTION_CLOSE_METHODDEF    \
     {"close", (PyCFunction)pysqlite_connection_close, METH_NOARGS, pysqlite_connection_close__doc__},
@@ -266,7 +268,9 @@ PyDoc_STRVAR(pysqlite_connection_commit__doc__,
 "commit($self, /)\n"
 "--\n"
 "\n"
-"Commit the current transaction.");
+"Commit any pending transaction to the database.\n"
+"\n"
+"If there is no open transaction, this method is a no-op.");
 
 #define PYSQLITE_CONNECTION_COMMIT_METHODDEF    \
     {"commit", (PyCFunction)pysqlite_connection_commit, METH_NOARGS, pysqlite_connection_commit__doc__},
@@ -284,7 +288,9 @@ PyDoc_STRVAR(pysqlite_connection_rollback__doc__,
 "rollback($self, /)\n"
 "--\n"
 "\n"
-"Roll back the current transaction.");
+"Roll back to the start of any pending transaction.\n"
+"\n"
+"If there is no open transaction, this method is a no-op.");
 
 #define PYSQLITE_CONNECTION_ROLLBACK_METHODDEF    \
     {"rollback", (PyCFunction)pysqlite_connection_rollback, METH_NOARGS, pysqlite_connection_rollback__doc__},
@@ -1231,4 +1237,4 @@ exit:
 #ifndef DESERIALIZE_METHODDEF
     #define DESERIALIZE_METHODDEF
 #endif /* !defined(DESERIALIZE_METHODDEF) */
-/*[clinic end generated code: output=fb8908674e9f25ff input=a9049054013a1b77]*/
+/*[clinic end generated code: output=8818c1c3ec9425aa input=a9049054013a1b77]*/

Modules/_sqlite/connection.c

@@ -470,12 +470,14 @@ blobopen_impl(pysqlite_Connection *self, const char *table, const char *col,
 /*[clinic input]
 _sqlite3.Connection.close as pysqlite_connection_close
 
-Closes the connection.
+Close the database connection.
+
+Any pending transaction is not committed implicitly.
 [clinic start generated code]*/
 
 static PyObject *
 pysqlite_connection_close_impl(pysqlite_Connection *self)
-/*[clinic end generated code: output=a546a0da212c9b97 input=3d58064bbffaa3d3]*/
+/*[clinic end generated code: output=a546a0da212c9b97 input=b3ed5b74f6fefc06]*/
 {
     if (!pysqlite_check_thread(self)) {
         return NULL;
@@ -522,12 +524,14 @@ int pysqlite_check_connection(pysqlite_Connection* con)
 /*[clinic input]
 _sqlite3.Connection.commit as pysqlite_connection_commit
 
-Commit the current transaction.
+Commit any pending transaction to the database.
+
+If there is no open transaction, this method is a no-op.
 [clinic start generated code]*/
 
 static PyObject *
 pysqlite_connection_commit_impl(pysqlite_Connection *self)
-/*[clinic end generated code: output=3da45579e89407f2 input=39c12c04dda276a8]*/
+/*[clinic end generated code: output=3da45579e89407f2 input=c8793c97c3446065]*/
 {
     if (!pysqlite_check_thread(self) || !pysqlite_check_connection(self)) {
         return NULL;
@@ -557,12 +561,14 @@ pysqlite_connection_commit_impl(pysqlite_Connection *self)
 /*[clinic input]
 _sqlite3.Connection.rollback as pysqlite_connection_rollback
 
-Roll back the current transaction.
+Roll back to the start of any pending transaction.
+
+If there is no open transaction, this method is a no-op.
 [clinic start generated code]*/
 
 static PyObject *
 pysqlite_connection_rollback_impl(pysqlite_Connection *self)
-/*[clinic end generated code: output=b66fa0d43e7ef305 input=12d4e8d068942830]*/
+/*[clinic end generated code: output=b66fa0d43e7ef305 input=7f60a2f1076f16b3]*/
 {
     if (!pysqlite_check_thread(self) || !pysqlite_check_connection(self)) {
         return NULL;