Fix psql's single transaction mode on client-side errors with -c/-f switches

psql --single-transaction is able to handle multiple -c and -f switches
in a single transaction since d5563d7d, but this had the surprising
behavior of forcing a transaction COMMIT even if psql failed with an
error in the client (for example incorrect path given to \copy), which
would generate an error, but still commit any changes that were already
applied in the backend.  This commit makes the behavior more consistent,
by enforcing a transaction ROLLBACK if any commands fail, both
client-side and backend-side, so as no changes are applied if one error
happens in any of them.

Some tests are added on HEAD to provide some coverage about all that.
Backend-side errors are unreliable as IPC::Run can complain on SIGPIPE
if psql quits before reading a query result, but that should work
properly in the case where any errors come from psql itself, which is
what the original report is about.

Reported-by: Christoph Berg
Author: Kyotaro Horiguchi, Michael Paquier
Discussion: https://postgr.es/m/17504-76b68018e130415e@postgresql.org
Backpatch-through: 10

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 47bf3342a59d2505acedf56302d5bca0938490e4..ababd371dfac93156525b1a5e253b98535471e45 100644 (file)
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -584,8 +584,10 @@ EOF
         <application>psql</application> to issue a <command>BEGIN</command> command
         before the first such option and a <command>COMMIT</command> command after
         the last one, thereby wrapping all the commands into a single
-        transaction.  This ensures that either all the commands complete
-        successfully, or no changes are applied.
+        transaction. If any of the commands fails, a
+        <command>ROLLBACK</command> command is sent instead. This ensures that
+        either all the commands complete successfully, or no changes are
+        applied.
        </para>
 
        <para>

diff --git a/src/bin/psql/startup.c b/src/bin/psql/startup.c
index ddff9039158605299a0c8ef04917363ed7732c9b..574f49d4c9bc3f1c5486917a8614e1f21b381f59 100644 (file)
--- a/src/bin/psql/startup.c
+++ b/src/bin/psql/startup.c
@@ -426,7 +426,9 @@ main(int argc, char *argv[])
 
                if (options.single_txn)
                {
-                       if ((res = PSQLexec("COMMIT")) == NULL)
+                       res = PSQLexec((successResult == EXIT_SUCCESS) ?
+                                                  "COMMIT" : "ROLLBACK");
+                       if (res == NULL)
                        {
                                if (pset.on_error_stop)
                                {

diff --git a/src/bin/psql/t/001_basic.pl b/src/bin/psql/t/001_basic.pl
index c3ed18e84da2fab138caa18b391a23e80beb2678..d7e20f0ac617c2246358e31a51f442d0e9a87ace 100644 (file)
--- a/src/bin/psql/t/001_basic.pl
+++ b/src/bin/psql/t/001_basic.pl
@@ -198,4 +198,68 @@ like(
 ^LOCATION: .*$/m,
        '\errverbose after \gdesc with error');
 
+# Check behavior when using multiple -c and -f switches.
+# Note that we cannot test backend-side errors as tests are unstable in this
+# case: IPC::Run can complain about a SIGPIPE if psql quits before reading a
+# query result.
+my $tempdir = PostgreSQL::Test::Utils::tempdir;
+$node->safe_psql('postgres', "CREATE TABLE tab_psql_single (a int);");
+$node->command_ok(
+       [
+               'psql',                                   '-X',
+               '--single-transaction',                   '-v',
+               'ON_ERROR_STOP=1',                        '-c',
+               'INSERT INTO tab_psql_single VALUES (1)', '-c',
+               'INSERT INTO tab_psql_single VALUES (2)'
+       ],
+       '--single-transaction and multiple -c switches');
+my $row_count =
+  $node->safe_psql('postgres', 'SELECT count(*) FROM tab_psql_single');
+is($row_count, '2',
+       '--single-transaction commits transaction, multiple -c switches');
+
+$node->command_fails(
+       [
+               'psql',                                   '-X',
+               '--single-transaction',                   '-v',
+               'ON_ERROR_STOP=1',                        '-c',
+               'INSERT INTO tab_psql_single VALUES (3)', '-c',
+               "\\copy tab_psql_single FROM '$tempdir/nonexistent'"
+       ],
+       '--single-transaction and multiple -c switches, error');
+$row_count =
+  $node->safe_psql('postgres', 'SELECT count(*) FROM tab_psql_single');
+is($row_count, '2',
+       'client-side error rolls back transaction, multiple -c switches');
+
+# Tests mixing files and commands.
+my $copy_sql_file   = "$tempdir/tab_copy.sql";
+my $insert_sql_file = "$tempdir/tab_insert.sql";
+append_to_file($copy_sql_file,
+       "\\copy tab_psql_single FROM '$tempdir/nonexistent';");
+append_to_file($insert_sql_file, 'INSERT INTO tab_psql_single VALUES (4);');
+$node->command_ok(
+       [
+               'psql',            '-X', '--single-transaction', '-v',
+               'ON_ERROR_STOP=1', '-f', $insert_sql_file,       '-f',
+               $insert_sql_file
+       ],
+       '--single-transaction and multiple -f switches');
+$row_count =
+  $node->safe_psql('postgres', 'SELECT count(*) FROM tab_psql_single');
+is($row_count, '4',
+       '--single-transaction commits transaction, multiple -f switches');
+
+$node->command_fails(
+       [
+               'psql',            '-X', '--single-transaction', '-v',
+               'ON_ERROR_STOP=1', '-f', $insert_sql_file,       '-f',
+               $copy_sql_file
+       ],
+       '--single-transaction and multiple -f switches, error');
+$row_count =
+  $node->safe_psql('postgres', 'SELECT count(*) FROM tab_psql_single');
+is($row_count, '4',
+       'client-side error rolls back transaction, multiple -f switches');
+
 done_testing();