better detection of missing return in exception handlers

Author: okbob

expected/plpgsql_check_active.out

@@ -3875,3 +3875,58 @@ select * from plpgsql_check_function('dyn_sql_4()');
 (2 rows)
 
 drop function dyn_sql_4();
+create or replace function test_bug(text)
+returns regproc as $$
+begin
+  return $1::regproc;
+  exception when undefined_function or invalid_name then
+    raise;
+end;
+$$ language plpgsql;
+-- should not raise a exception
+select * from plpgsql_check_function('test_bug');
+ plpgsql_check_function 
+------------------------
+(0 rows)
+
+create or replace function test_bug(text)
+returns regproc as $$
+begin
+  return $1::regproc;
+  exception when undefined_function or invalid_name then
+    raise notice '%', $1; -- bug
+end;
+$$ language plpgsql;
+select test_bug('kuku'); -- should to fail
+NOTICE:  kuku
+ERROR:  control reached end of function without RETURN
+CONTEXT:  PL/pgSQL function test_bug(text)
+select * from plpgsql_check_function('test_bug');
+                       plpgsql_check_function                       
+--------------------------------------------------------------------
+ warning extra:2F005:control reached end of function without RETURN
+(1 row)
+
+drop function test_bug(text);
+create or replace function test_bug(text)
+returns regproc as $$
+begin
+  return $1::regproc;
+  exception when undefined_function or invalid_name then
+    raise notice '%', $1;
+    return NULL;
+end;
+$$ language plpgsql;
+select test_bug('kuku'); -- should be ok
+NOTICE:  kuku
+ test_bug 
+----------
+ 
+(1 row)
+
+select * from plpgsql_check_function('test_bug');
+ plpgsql_check_function 
+------------------------
+(0 rows)
+
+drop function test_bug(text);

sql/plpgsql_check_active.sql

@@ -2825,3 +2825,45 @@ select * from dyn_sql_4();
 select * from plpgsql_check_function('dyn_sql_4()');
 
 drop function dyn_sql_4();
+
+create or replace function test_bug(text)
+returns regproc as $$
+begin
+  return $1::regproc;
+  exception when undefined_function or invalid_name then
+    raise;
+end;
+$$ language plpgsql;
+
+-- should not raise a exception
+select * from plpgsql_check_function('test_bug');
+
+create or replace function test_bug(text)
+returns regproc as $$
+begin
+  return $1::regproc;
+  exception when undefined_function or invalid_name then
+    raise notice '%', $1; -- bug
+end;
+$$ language plpgsql;
+
+select test_bug('kuku'); -- should to fail
+
+select * from plpgsql_check_function('test_bug');
+
+drop function test_bug(text);
+
+create or replace function test_bug(text)
+returns regproc as $$
+begin
+  return $1::regproc;
+  exception when undefined_function or invalid_name then
+    raise notice '%', $1;
+    return NULL;
+end;
+$$ language plpgsql;
+
+select test_bug('kuku'); -- should be ok
+select * from plpgsql_check_function('test_bug');
+
+drop function test_bug(text);

src/stmtwalk.c

@@ -349,6 +349,8 @@ plpgsql_check_stmt(PLpgSQL_checkstate *cstate, PLpgSQL_stmt *stmt, int *closing,
 						}
 						else
 						{
+							closing_handlers = *closing;
+
 							foreach(l, stmt_block->exceptions->exc_list)
 							{
 								PLpgSQL_exception *exception = (PLpgSQL_exception *) lfirst(l);
@@ -362,8 +364,12 @@ plpgsql_check_stmt(PLpgSQL_checkstate *cstate, PLpgSQL_stmt *stmt, int *closing,
 																 -1);
 							}
 
-							if (closing_handlers != *closing)
-								*closing = PLPGSQL_CHECK_POSSIBLY_CLOSED;
+							*closing = closing_handlers;
+
+							if (closing_handlers == PLPGSQL_CHECK_CLOSED_BY_EXCEPTIONS)
+								*exceptions = exceptions_transformed;
+							else
+								*exceptions = NIL;
 						}
 
 						/*
@@ -1151,6 +1157,7 @@ plpgsql_check_stmt(PLpgSQL_checkstate *cstate, PLpgSQL_stmt *stmt, int *closing,
 									  stmt_dynexecute->params);
 				}
 				break;
+
 			case PLPGSQL_STMT_OPEN:
 				{
 					PLpgSQL_stmt_open *stmt_open = (PLpgSQL_stmt_open *) stmt;