In PL/PgSQL, allow a block's label to be optionally specified at the

end of the block:

<<label>>
begin
    ...
end label;

Similarly for loops. This is per PL/SQL. Update the documentation and
add regression tests. Patch from Pavel Stehule, code review by Neil
Conway.

2 files changed, 107 insertions, 4 deletions

diff --git a/src/test/regress/expected/plpgsql.out b/src/test/regress/expected/plpgsql.out
index a74b0e54666..42dcad5c2fb 100644
--- a/src/test/regress/expected/plpgsql.out
+++ b/src/test/regress/expected/plpgsql.out
@@ -2491,7 +2491,7 @@ NOTICE:  {10,20,30}; 20; xyz; xyzabc; (10,aaa,,30); <NULL>
 (1 row)
 
 drop function raise_exprs();
--- continue statement 
+-- continue statement
 create table conttesttbl(idx serial, v integer);
 NOTICE:  CREATE TABLE will create implicit sequence "conttesttbl_idx_seq" for serial column "conttesttbl.idx"
 insert into conttesttbl(v) values(10);
@@ -2532,7 +2532,7 @@ begin
   for _i in 1..10 loop
     begin
       -- applies to outer loop, not the nested begin block
-      continue when _i < 5; 
+      continue when _i < 5;
       raise notice '%', _i;
     end;
   end loop;
@@ -2666,3 +2666,58 @@ drop function continue_test1();
 drop function continue_test2();
 drop function continue_test3();
 drop table conttesttbl;
+-- verbose end block and end loop
+create function end_label1() returns void as $$
+<<blbl>>
+begin
+  <<flbl1>>
+  for _i in 1 .. 10 loop
+    exit flbl1;
+  end loop flbl1;
+  <<flbl2>>
+  for _i in 1 .. 10 loop
+    exit flbl2;
+  end loop;
+end blbl;
+$$ language plpgsql;
+select end_label1();
+ end_label1 
+------------
+ 
+(1 row)
+
+drop function end_label1();
+-- should fail: undefined end label
+create function end_label2() returns void as $$
+begin
+  for _i in 1 .. 10 loop
+    exit;
+  end loop flbl1;
+end;
+$$ language plpgsql;
+ERROR:  no such label at or near "flbl1" at character 101
+LINE 5:   end loop flbl1;
+                   ^
+-- should fail: end label does not match start label
+create function end_label3() returns void as $$
+<<outer_label>>
+begin
+  <<inner_label>>
+  for _i in 1 .. 10 loop
+    exit;
+  end loop outer_label;
+end;
+$$ language plpgsql;
+ERROR:  end label "outer_label" differs from block's label "inner_label"
+CONTEXT:  compile of PL/pgSQL function "end_label3" near line 6
+-- should fail: end label on a block without a start label
+create function end_label4() returns void as $$
+<<outer_label>>
+begin
+  for _i in 1 .. 10 loop
+    exit;
+  end loop outer_label;
+end;
+$$ language plpgsql;
+ERROR:  end label "outer_label" specified for unlabelled block
+CONTEXT:  compile of PL/pgSQL function "end_label4" near line 5
diff --git a/src/test/regress/sql/plpgsql.sql b/src/test/regress/sql/plpgsql.sql
index b0d49c0f321..3432b5556cc 100644
--- a/src/test/regress/sql/plpgsql.sql
+++ b/src/test/regress/sql/plpgsql.sql
@@ -2113,7 +2113,7 @@ end;$$ language plpgsql;
 select raise_exprs();
 drop function raise_exprs();
 
--- continue statement 
+-- continue statement
 create table conttesttbl(idx serial, v integer);
 insert into conttesttbl(v) values(10);
 insert into conttesttbl(v) values(20);
@@ -2154,7 +2154,7 @@ begin
   for _i in 1..10 loop
     begin
       -- applies to outer loop, not the nested begin block
-      continue when _i < 5; 
+      continue when _i < 5;
       raise notice '%', _i;
     end;
   end loop;
@@ -2232,3 +2232,51 @@ drop function continue_test1();
 drop function continue_test2();
 drop function continue_test3();
 drop table conttesttbl;
+
+-- verbose end block and end loop
+create function end_label1() returns void as $$
+<<blbl>>
+begin
+  <<flbl1>>
+  for _i in 1 .. 10 loop
+    exit flbl1;
+  end loop flbl1;
+  <<flbl2>>
+  for _i in 1 .. 10 loop
+    exit flbl2;
+  end loop;
+end blbl;
+$$ language plpgsql;
+
+select end_label1();
+drop function end_label1();
+
+-- should fail: undefined end label
+create function end_label2() returns void as $$
+begin
+  for _i in 1 .. 10 loop
+    exit;
+  end loop flbl1;
+end;
+$$ language plpgsql;
+
+-- should fail: end label does not match start label
+create function end_label3() returns void as $$
+<<outer_label>>
+begin
+  <<inner_label>>
+  for _i in 1 .. 10 loop
+    exit;
+  end loop outer_label;
+end;
+$$ language plpgsql;
+
+-- should fail: end label on a block without a start label
+create function end_label4() returns void as $$
+<<outer_label>>
+begin
+  for _i in 1 .. 10 loop
+    exit;
+  end loop outer_label;
+end;
+$$ language plpgsql;