Fix EXIT out of outermost block in plpgsql.

Ordinarily, using EXIT this way would draw "control reached end of
function without RETURN".  However, if the function is one where we
don't require an explicit RETURN (such as a DO block), that should
not happen.  It did anyway, because add_dummy_return() neglected to
account for the case.

Per report from Herwig Goemans.  Back-patch to all supported branches.

Discussion: https://postgr.es/m/868ae948-e3ca-c7ec-95a6-83cfc08ef750@gmail.com

3 files changed, 27 insertions, 2 deletions

diff --git a/src/pl/plpgsql/src/expected/plpgsql_control.out b/src/pl/plpgsql/src/expected/plpgsql_control.out
index fbfc939eae9..328bd485861 100644
--- a/src/pl/plpgsql/src/expected/plpgsql_control.out
+++ b/src/pl/plpgsql/src/expected/plpgsql_control.out
@@ -413,6 +413,17 @@ begin
   raise notice 'should get here';
 end$$;
 NOTICE:  should get here
+-- check exit out of outermost block
+do $$
+<<outerblock>>
+begin
+  <<innerblock>>
+  begin
+    exit outerblock;
+    raise notice 'should not get here';
+  end;
+  raise notice 'should not get here, either';
+end$$;
 -- unlabeled exit does match a while loop
 do $$
 begin
diff --git a/src/pl/plpgsql/src/pl_comp.c b/src/pl/plpgsql/src/pl_comp.c
index a68a2077c36..f5b1d5c4fac 100644
--- a/src/pl/plpgsql/src/pl_comp.c
+++ b/src/pl/plpgsql/src/pl_comp.c
@@ -1038,9 +1038,11 @@ add_dummy_return(PLpgSQL_function *function)
 	/*
 	 * If the outer block has an EXCEPTION clause, we need to make a new outer
 	 * block, since the added RETURN shouldn't act like it is inside the
-	 * EXCEPTION clause.
+	 * EXCEPTION clause.  Likewise, if it has a label, wrap it in a new outer
+	 * block so that EXIT doesn't skip the RETURN.
 	 */
-	if (function->action->exceptions != NULL)
+	if (function->action->exceptions != NULL ||
+		function->action->label != NULL)
 	{
 		PLpgSQL_stmt_block *new;
 
diff --git a/src/pl/plpgsql/src/sql/plpgsql_control.sql b/src/pl/plpgsql/src/sql/plpgsql_control.sql
index 61d6ca64513..ed7231134f4 100644
--- a/src/pl/plpgsql/src/sql/plpgsql_control.sql
+++ b/src/pl/plpgsql/src/sql/plpgsql_control.sql
@@ -311,6 +311,18 @@ begin
   raise notice 'should get here';
 end$$;
 
+-- check exit out of outermost block
+do $$
+<<outerblock>>
+begin
+  <<innerblock>>
+  begin
+    exit outerblock;
+    raise notice 'should not get here';
+  end;
+  raise notice 'should not get here, either';
+end$$;
+
 -- unlabeled exit does match a while loop
 do $$
 begin