pgbench: fix misprocessing of some nested \if constructs.

An \if command appearing within a false (not-to-be-executed) \if
branch was incorrectly treated the same as \elif.  This could allow
statements within the inner \if to be executed when they should
not be.  Also the missing inner \if stack entry would result in an
assertion failure (in assert-enabled builds) when the final \endif
is reached.

Report and patch by Michail Nikolaev.  Back-patch to all
supported branches.

Discussion: https://postgr.es/m/CANtu0oiA1ke=SP6tauhNqkUdv5QFsJtS1p=aOOf_iU+EhyKkjQ@mail.gmail.com

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index c7f8431841af7e998e045ee77ba86516ae7ead79..1f6cb0e6038c4edea2874f934d6e57326e249d42 100644 (file)
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -3446,8 +3446,14 @@ advanceConnectionState(TState *thread, CState *st, StatsData *agg)
                        switch (conditional_stack_peek(st->cstack))
                        {
                            case IFSTATE_FALSE:
-                               if (command->meta == META_IF ||
-                                   command->meta == META_ELIF)
+                               if (command->meta == META_IF)
+                               {
+                                   /* nested if in skipped branch - ignore */
+                                   conditional_stack_push(st->cstack,
+                                                          IFSTATE_IGNORED);
+                                   st->command++;
+                               }
+                               else if (command->meta == META_ELIF)
                                {
                                    /* we must evaluate the condition */
                                    st->state = CSTATE_START_COMMAND;
@@ -3466,11 +3472,7 @@ advanceConnectionState(TState *thread, CState *st, StatsData *agg)
                                    conditional_stack_pop(st->cstack);
                                    if (conditional_active(st->cstack))
                                        st->state = CSTATE_START_COMMAND;
-
-                                   /*
-                                    * else state remains in
-                                    * CSTATE_SKIP_COMMAND
-                                    */
+                                   /* else state remains CSTATE_SKIP_COMMAND */
                                    st->command++;
                                }
                                break;

diff --git a/src/bin/pgbench/t/001_pgbench_with_server.pl b/src/bin/pgbench/t/001_pgbench_with_server.pl
index 4f716c6c073926f1cbca73976293ca2d75487fb6..fbd45c766cc67143ce033c0c067591db056e44ae 100644 (file)
--- a/src/bin/pgbench/t/001_pgbench_with_server.pl
+++ b/src/bin/pgbench/t/001_pgbench_with_server.pl
@@ -622,6 +622,56 @@ SELECT :v0, :v1, :v2, :v3;
 }
    });
 
+# test nested \if constructs
+$node->pgbench(
+   '--no-vacuum --client=1 --transactions=1',
+   0,
+   [qr{actually processed}],
+   [qr{^$}],
+   'nested ifs',
+   {
+       'pgbench_nested_if' => q(
+           \if false
+               SELECT 1 / 0;
+               \if true
+                   SELECT 1 / 0;
+               \elif true
+                   SELECT 1 / 0;
+               \else
+                   SELECT 1 / 0;
+               \endif
+               SELECT 1 / 0;
+           \elif false
+               \if true
+                   SELECT 1 / 0;
+               \elif true
+                   SELECT 1 / 0;
+               \else
+                   SELECT 1 / 0;
+               \endif
+           \else
+               \if false
+                   SELECT 1 / 0;
+               \elif false
+                   SELECT 1 / 0;
+               \else
+                   SELECT 'correct';
+               \endif
+           \endif
+           \if true
+               SELECT 'correct';
+           \else
+               \if true
+                   SELECT 1 / 0;
+               \elif true
+                   SELECT 1 / 0;
+               \else
+                   SELECT 1 / 0;
+               \endif
+           \endif
+       )
+   });
+
 # random determinism when seeded
 $node->safe_psql('postgres',
    'CREATE UNLOGGED TABLE seeded_random(seed INT8 NOT NULL, rand TEXT NOT NULL, val INTEGER NOT NULL);'