Don't fail for bad GUCs in CREATE FUNCTION with check_function_bodies off.

The previous coding attempted to activate all the GUC settings specified
in SET clauses, so that the function validator could operate in the GUC
environment expected by the function body.  However, this is problematic
when restoring a dump, since the SET clauses might refer to database
objects that don't exist yet.  We already have the parameter
check_function_bodies that's meant to prevent forward references in
function definitions from breaking dumps, so let's change CREATE FUNCTION
to not install the SET values if check_function_bodies is off.

Authors of function validators were already advised not to make any
"context sensitive" checks when check_function_bodies is off, if indeed
they're checking anything at all in that mode.  But extend the
documentation to point out the GUC issue in particular.

(Note that we still check the SET clauses to some extent; the behavior
with !check_function_bodies is now approximately equivalent to what ALTER
DATABASE/ROLE have been doing for awhile with context-dependent GUCs.)

This problem can be demonstrated in all active branches, so back-patch
all the way.

2 files changed, 34 insertions, 0 deletions

diff --git a/src/test/regress/expected/guc.out b/src/test/regress/expected/guc.out
index 271706d31e9..7b5a624eb8f 100644
--- a/src/test/regress/expected/guc.out
+++ b/src/test/regress/expected/guc.out
@@ -718,3 +718,19 @@ select myfunc(1), current_setting('work_mem');
  2MB    | 2MB
 (1 row)
 
+-- Normally, CREATE FUNCTION should complain about invalid values in
+-- function SET options; but not if check_function_bodies is off,
+-- because that creates ordering hazards for pg_dump
+create function func_with_bad_set() returns int as $$ select 1 $$
+language sql
+set default_text_search_config = no_such_config;
+NOTICE:  text search configuration "no_such_config" does not exist
+ERROR:  invalid value for parameter "default_text_search_config": "no_such_config"
+set check_function_bodies = off;
+create function func_with_bad_set() returns int as $$ select 1 $$
+language sql
+set default_text_search_config = no_such_config;
+NOTICE:  text search configuration "no_such_config" does not exist
+select func_with_bad_set();
+ERROR:  invalid value for parameter "default_text_search_config": "no_such_config"
+reset check_function_bodies;
diff --git a/src/test/regress/sql/guc.sql b/src/test/regress/sql/guc.sql
index 0c217923814..3de8a6b55d6 100644
--- a/src/test/regress/sql/guc.sql
+++ b/src/test/regress/sql/guc.sql
@@ -257,3 +257,21 @@ set work_mem = '1MB';
 select myfunc(0);
 select current_setting('work_mem');
 select myfunc(1), current_setting('work_mem');
+
+-- Normally, CREATE FUNCTION should complain about invalid values in
+-- function SET options; but not if check_function_bodies is off,
+-- because that creates ordering hazards for pg_dump
+
+create function func_with_bad_set() returns int as $$ select 1 $$
+language sql
+set default_text_search_config = no_such_config;
+
+set check_function_bodies = off;
+
+create function func_with_bad_set() returns int as $$ select 1 $$
+language sql
+set default_text_search_config = no_such_config;
+
+select func_with_bad_set();
+
+reset check_function_bodies;