From b1de90699e73a081ac450420b7d4f3fd1d49981b Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 13 Sep 2021 12:42:03 -0400
Subject: [PATCH] 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
---
 src/pl/plpgsql/src/expected/plpgsql_control.out | 11 +++++++++++
 src/pl/plpgsql/src/pl_comp.c                    |  6 ++++--
 src/pl/plpgsql/src/sql/plpgsql_control.sql      | 12 ++++++++++++
 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 73b23a35e5..e09a7aa98a 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 a1d45d51cd..c99065a3be 100644
--- a/src/pl/plpgsql/src/pl_comp.c
+++ b/src/pl/plpgsql/src/pl_comp.c
@@ -1033,9 +1033,11 @@ 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 61d6ca6451..ed7231134f 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