Improve consistency of error reporting in GUC assign_hook routines. Some

were reporting ERROR for interactive assignments and LOG for other cases,
some were saying nothing for non-interactive cases, and a few did yet other
things.  Make them use a new function GUC_complaint_elevel() to establish
a reasonably uniform policy about how to report.  There are still a few
edge cases such as assign_search_path(), but it's much better than before.
Per gripe from Devrim Gunduz and subsequent discussion.

As noted by Alvaro, it'd be better to fold these custom messages into the
standard "invalid parameter value" complaint from guc.c, perhaps as the DETAIL
field.  However that will require more redesign than seems prudent for 8.3.
This is a relatively safe, low-impact change that we can afford to risk now.

1 files changed, 68 insertions, 33 deletions

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 421449c1bd3..a222eb9023e 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.427 2007/12/27 13:02:48 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.428 2007/12/28 00:23:23 tgl Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -4157,7 +4157,7 @@ call_string_assign_hook(GucStringAssignHook assign_hook,
  * If there is an error (non-existing option, invalid value) then an
  * ereport(ERROR) is thrown *unless* this is called in a context where we
  * don't want to ereport (currently, startup or SIGHUP config file reread).
- * In that case we write a suitable error message via ereport(DEBUG) and
+ * In that case we write a suitable error message via ereport(LOG) and
  * return false. This is working around the deficiencies in the ereport
  * mechanism, so don't blame me.  In all other cases, the function
  * returns true, including cases where the input is valid but we chose
@@ -4180,7 +4180,7 @@ set_config_option(const char *name, const char *value,
 		 * To avoid cluttering the log, only the postmaster bleats loudly
 		 * about problems with the config file.
 		 */
-		elevel = IsUnderPostmaster ? DEBUG2 : LOG;
+		elevel = IsUnderPostmaster ? DEBUG3 : LOG;
 	}
 	else if (source == PGC_S_DATABASE || source == PGC_S_USER)
 		elevel = INFO;
@@ -4804,6 +4804,41 @@ IsSuperuserConfigOption(const char *name)
 
 
 /*
+ * GUC_complaint_elevel
+ *		Get the ereport error level to use in an assign_hook's error report.
+ *
+ * This should be used by assign hooks that want to emit a custom error
+ * report (in addition to the generic "invalid value for option FOO" that
+ * guc.c will provide).  Note that the result might be ERROR or a lower
+ * level, so the caller must be prepared for control to return from ereport,
+ * or not.  If control does return, return false/NULL from the hook function.
+ *
+ * At some point it'd be nice to replace this with a mechanism that allows
+ * the custom message to become the DETAIL line of guc.c's generic message.
+ */
+int
+GUC_complaint_elevel(GucSource source)
+{
+	int			elevel;
+
+	if (source == PGC_S_FILE)
+	{
+		/*
+		 * To avoid cluttering the log, only the postmaster bleats loudly
+		 * about problems with the config file.
+		 */
+		elevel = IsUnderPostmaster ? DEBUG3 : LOG;
+	}
+	else if (source < PGC_S_INTERACTIVE)
+		elevel = LOG;
+	else
+		elevel = ERROR;
+
+	return elevel;
+}
+
+
+/*
  * flatten_set_variable_args
  *		Given a parsenode List as emitted by the grammar for SET,
  *		convert to the flat string representation used by GUC.
@@ -6406,9 +6441,8 @@ assign_log_destination(const char *value, bool doit, GucSource source)
 		/* syntax error in list */
 		pfree(rawstring);
 		list_free(elemlist);
-		if (source >= PGC_S_INTERACTIVE)
-			ereport(ERROR,
-					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+		ereport(GUC_complaint_elevel(source),
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 			errmsg("invalid list syntax for parameter \"log_destination\"")));
 		return NULL;
 	}
@@ -6431,9 +6465,8 @@ assign_log_destination(const char *value, bool doit, GucSource source)
 #endif
 		else
 		{
-			if (source >= PGC_S_INTERACTIVE)
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+			ereport(GUC_complaint_elevel(source),
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				  errmsg("unrecognized \"log_destination\" key word: \"%s\"",
 						 tok)));
 			pfree(rawstring);
@@ -6719,10 +6752,9 @@ assign_phony_autocommit(bool newval, bool doit, GucSource source)
 {
 	if (!newval)
 	{
-		if (doit && source >= PGC_S_INTERACTIVE)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("SET AUTOCOMMIT TO OFF is no longer supported")));
+		ereport(GUC_complaint_elevel(source),
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("SET AUTOCOMMIT TO OFF is no longer supported")));
 		return false;
 	}
 	return true;
@@ -6791,9 +6823,12 @@ assign_debug_assertions(bool newval, bool doit, GucSource source)
 {
 #ifndef USE_ASSERT_CHECKING
 	if (newval)
-		ereport(ERROR,
+	{
+		ereport(GUC_complaint_elevel(source),
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 			   errmsg("assertion checking is not supported by this build")));
+		return false;
+	}
 #endif
 	return true;
 }
@@ -6803,9 +6838,12 @@ assign_ssl(bool newval, bool doit, GucSource source)
 {
 #ifndef USE_SSL
 	if (newval)
-		ereport(ERROR,
+	{
+		ereport(GUC_complaint_elevel(source),
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("SSL is not supported by this build")));
+		return false;
+	}
 #endif
 	return true;
 }
@@ -6815,12 +6853,11 @@ assign_stage_log_stats(bool newval, bool doit, GucSource source)
 {
 	if (newval && log_statement_stats)
 	{
-		if (source >= PGC_S_INTERACTIVE)
-			ereport(ERROR,
-					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-					 errmsg("cannot enable parameter when \"log_statement_stats\" is true")));
+		ereport(GUC_complaint_elevel(source),
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("cannot enable parameter when \"log_statement_stats\" is true")));
 		/* source == PGC_S_OVERRIDE means do it anyway, eg at xact abort */
-		else if (source != PGC_S_OVERRIDE)
+		if (source != PGC_S_OVERRIDE)
 			return false;
 	}
 	return true;
@@ -6832,14 +6869,13 @@ assign_log_stats(bool newval, bool doit, GucSource source)
 	if (newval &&
 		(log_parser_stats || log_planner_stats || log_executor_stats))
 	{
-		if (source >= PGC_S_INTERACTIVE)
-			ereport(ERROR,
-					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-					 errmsg("cannot enable \"log_statement_stats\" when "
-							"\"log_parser_stats\", \"log_planner_stats\", "
-							"or \"log_executor_stats\" is true")));
+		ereport(GUC_complaint_elevel(source),
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("cannot enable \"log_statement_stats\" when "
+						"\"log_parser_stats\", \"log_planner_stats\", "
+						"or \"log_executor_stats\" is true")));
 		/* source == PGC_S_OVERRIDE means do it anyway, eg at xact abort */
-		else if (source != PGC_S_OVERRIDE)
+		if (source != PGC_S_OVERRIDE)
 			return false;
 	}
 	return true;
@@ -6851,12 +6887,11 @@ assign_transaction_read_only(bool newval, bool doit, GucSource source)
 	/* Can't go to r/w mode inside a r/o transaction */
 	if (newval == false && XactReadOnly && IsSubTransaction())
 	{
-		if (source >= PGC_S_INTERACTIVE)
-			ereport(ERROR,
-					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-					 errmsg("cannot set transaction read-write mode inside a read-only transaction")));
+		ereport(GUC_complaint_elevel(source),
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("cannot set transaction read-write mode inside a read-only transaction")));
 		/* source == PGC_S_OVERRIDE means do it anyway, eg at xact abort */
-		else if (source != PGC_S_OVERRIDE)
+		if (source != PGC_S_OVERRIDE)
 			return false;
 	}
 	return true;
@@ -6934,7 +6969,7 @@ assign_timezone_abbreviations(const char *newval, bool doit, GucSource source)
 		 * and we use WARNING message level.
 		 */
 		if (source == PGC_S_FILE)
-			elevel = IsUnderPostmaster ? DEBUG2 : LOG;
+			elevel = IsUnderPostmaster ? DEBUG3 : LOG;
 		else
 			elevel = WARNING;
 		if (!load_tzoffsets(newval, doit, elevel))