Update comments concerning PGC_S_TEST.

This GUC context value was once only used by ALTER DATABASE SET and
ALTER USER SET.  That's not true anymore, though, so rewrite the
comments to be a bit more general.

Patch in HEAD only, since this is just an internal documentation issue.

1 files changed, 9 insertions, 5 deletions

diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index d497b1f654..99211c1f6c 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -72,11 +72,15 @@ typedef enum
  * dividing line between "interactive" and "non-interactive" sources for
  * error reporting purposes.
  *
- * PGC_S_TEST is used when testing values to be stored as per-database or
- * per-user defaults ("doit" will always be false, so this never gets stored
- * as the actual source of any value).	This is an interactive case, but
- * it needs its own source value because some assign hooks need to make
- * different validity checks in this case.
+ * PGC_S_TEST is used when testing values to be used later ("doit" will always
+ * be false, so this never gets stored as the actual source of any value).
+ * For example, ALTER DATABASE/ROLE tests proposed per-database or per-user
+ * defaults this way, and CREATE FUNCTION tests proposed function SET clauses
+ * this way.  This is an interactive case, but it needs its own source value
+ * because some assign hooks need to make different validity checks in this
+ * case.  In particular, references to nonexistent database objects generally
+ * shouldn't throw hard errors in this case, at most NOTICEs, since the
+ * objects might exist by the time the setting is used for real.
  *
  * NB: see GucSource_Names in guc.c if you change this.
  */