Tweak FOR UPDATE/SHARE error message wording (again)

In commit 0ac5ad51 I changed some error messages from "FOR
UPDATE/SHARE" to a rather long gobbledygook which nobody liked.  Then,
in commit cb9b66d3 I changed them again, but the alternative chosen
there was deemed suboptimal by Peter Eisentraut, who in message
1373937980.20441.8.camel@vanquo.pezone.net proposed an alternative
involving a dynamically-constructed string based on the actual locking
strength specified in the SQL command.  This patch implements that
suggestion.

src/backend/optimizer/plan/initsplan.c

@@ -26,6 +26,7 @@
 #include "optimizer/prep.h"
 #include "optimizer/restrictinfo.h"
 #include "optimizer/var.h"
+#include "parser/analyze.h"
 #include "rewrite/rewriteManip.h"
 #include "utils/lsyscache.h"
 
@@ -883,7 +884,10 @@ make_outerjoininfo(PlannerInfo *root,
 			(jointype == JOIN_FULL && bms_is_member(rc->rti, left_rels)))
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("row-level locks cannot be applied to the nullable side of an outer join")));
+					 /*------
+					  translator: %s is a SQL row locking clause such as FOR UPDATE */
+					 errmsg("%s cannot be applied to the nullable side of an outer join",
+							LCS_asString(rc->strength))));
 	}
 
 	sjinfo->syn_lefthand = left_rels;

src/backend/optimizer/plan/planner.c

@@ -1107,7 +1107,11 @@ grouping_planner(PlannerInfo *root, double tuple_fraction)
 		if (parse->rowMarks)
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("row-level locks are not allowed with UNION/INTERSECT/EXCEPT")));
+					 /*------
+					   translator: %s is a SQL row locking clause such as FOR UPDATE */
+					 errmsg("%s is not allowed with UNION/INTERSECT/EXCEPT",
+							LCS_asString(((RowMarkClause *)
+										  linitial(parse->rowMarks))->strength))));
 
 		/*
 		 * Calculate pathkeys that represent result ordering requirements

src/backend/parser/analyze.c

@@ -1221,7 +1221,11 @@ transformValuesClause(ParseState *pstate, SelectStmt *stmt)
 	if (stmt->lockingClause)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-			 errmsg("SELECT FOR UPDATE/SHARE cannot be applied to VALUES")));
+				 /*------
+				   translator: %s is a SQL row locking clause such as FOR UPDATE */
+				 errmsg("%s cannot be applied to VALUES",
+						LCS_asString(((LockingClause *)
+									  linitial(stmt->lockingClause))->strength))));
 
 	qry->rtable = pstate->p_rtable;
 	qry->jointree = makeFromExpr(pstate->p_joinlist, NULL);
@@ -1312,7 +1316,11 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	if (lockingClause)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("SELECT FOR UPDATE/SHARE is not allowed with UNION/INTERSECT/EXCEPT")));
+				 /*------
+				   translator: %s is a SQL row locking clause such as FOR UPDATE */
+				 errmsg("%s is not allowed with UNION/INTERSECT/EXCEPT",
+						LCS_asString(((LockingClause *)
+									  linitial(lockingClause))->strength))));
 
 	/* Process the WITH clause independently of all else */
 	if (withClause)
@@ -1506,7 +1514,11 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt,
 	if (stmt->lockingClause)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("SELECT FOR UPDATE/SHARE is not allowed with UNION/INTERSECT/EXCEPT")));
+				 /*------
+				   translator: %s is a SQL row locking clause such as FOR UPDATE */
+				 errmsg("%s is not allowed with UNION/INTERSECT/EXCEPT",
+						LCS_asString(((LockingClause *)
+									  linitial(stmt->lockingClause))->strength))));
 
 	/*
 	 * If an internal node of a set-op tree has ORDER BY, LIMIT, FOR UPDATE,
@@ -2063,21 +2075,33 @@ transformDeclareCursorStmt(ParseState *pstate, DeclareCursorStmt *stmt)
 	if (result->rowMarks != NIL && (stmt->options & CURSOR_OPT_HOLD))
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("DECLARE CURSOR WITH HOLD ... FOR UPDATE/SHARE is not supported"),
+				 /*------
+				   translator: %s is a SQL row locking clause such as FOR UPDATE */
+				 errmsg("DECLARE CURSOR WITH HOLD ... %s is not supported",
+						LCS_asString(((RowMarkClause *)
+									  linitial(result->rowMarks))->strength)),
 				 errdetail("Holdable cursors must be READ ONLY.")));
 
 	/* FOR UPDATE and SCROLL are not compatible */
 	if (result->rowMarks != NIL && (stmt->options & CURSOR_OPT_SCROLL))
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-		errmsg("DECLARE SCROLL CURSOR ... FOR UPDATE/SHARE is not supported"),
+				 /*------
+				   translator: %s is a SQL row locking clause such as FOR UPDATE */
+				 errmsg("DECLARE SCROLL CURSOR ... %s is not supported",
+						LCS_asString(((RowMarkClause *)
+									  linitial(result->rowMarks))->strength)),
 				 errdetail("Scrollable cursors must be READ ONLY.")));
 
 	/* FOR UPDATE and INSENSITIVE are not compatible */
 	if (result->rowMarks != NIL && (stmt->options & CURSOR_OPT_INSENSITIVE))
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("DECLARE INSENSITIVE CURSOR ... FOR UPDATE/SHARE is not supported"),
+				 /*------
+				   translator: %s is a SQL row locking clause such as FOR UPDATE */
+				 errmsg("DECLARE INSENSITIVE CURSOR ... %s is not supported",
+						LCS_asString(((RowMarkClause *)
+									  linitial(result->rowMarks))->strength)),
 				 errdetail("Insensitive cursors must be READ ONLY.")));
 
 	/* We won't need the raw querytree any more */
@@ -2196,6 +2220,23 @@ transformCreateTableAsStmt(ParseState *pstate, CreateTableAsStmt *stmt)
 }
 
 
+char *
+LCS_asString(LockClauseStrength strength)
+{
+	switch (strength)
+	{
+		case LCS_FORKEYSHARE:
+			return "FOR KEY SHARE";
+		case LCS_FORSHARE:
+			return "FOR SHARE";
+		case LCS_FORNOKEYUPDATE:
+			return "FOR NO KEY UPDATE";
+		case LCS_FORUPDATE:
+			return "FOR UPDATE";
+	}
+	return "FOR some";	/* shouldn't happen */
+}
+
 /*
  * Check for features that are not supported with FOR [KEY] UPDATE/SHARE.
  *
@@ -2207,31 +2248,59 @@ CheckSelectLocking(Query *qry)
 	if (qry->setOperations)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("row-level locks are not allowed with UNION/INTERSECT/EXCEPT")));
+				 /*------
+				   translator: %s is a SQL row locking clause such as FOR UPDATE */
+				 errmsg("%s is not allowed with UNION/INTERSECT/EXCEPT",
+						LCS_asString(((RowMarkClause *)
+									  linitial(qry->rowMarks))->strength))));
 	if (qry->distinctClause != NIL)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-			errmsg("row-level locks are not allowed with DISTINCT clause")));
+				 /*------
+				   translator: %s is a SQL row locking clause such as FOR UPDATE */
+				 errmsg("%s is not allowed with DISTINCT clause",
+						LCS_asString(((RowMarkClause *)
+									  linitial(qry->rowMarks))->strength))));
 	if (qry->groupClause != NIL)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-			errmsg("row-level locks are not allowed with GROUP BY clause")));
+				 /*------
+				   translator: %s is a SQL row locking clause such as FOR UPDATE */
+				 errmsg("%s is not allowed with GROUP BY clause",
+						LCS_asString(((RowMarkClause *)
+									  linitial(qry->rowMarks))->strength))));
 	if (qry->havingQual != NULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-			  errmsg("row-level locks are not allowed with HAVING clause")));
+				 /*------
+				   translator: %s is a SQL row locking clause such as FOR UPDATE */
+				 errmsg("%s is not allowed with HAVING clause",
+						LCS_asString(((RowMarkClause *)
+									  linitial(qry->rowMarks))->strength))));
 	if (qry->hasAggs)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-		errmsg("row-level locks are not allowed with aggregate functions")));
+				 /*------
+				   translator: %s is a SQL row locking clause such as FOR UPDATE */
+				 errmsg("%s is not allowed with aggregate functions",
+						LCS_asString(((RowMarkClause *)
+									  linitial(qry->rowMarks))->strength))));
 	if (qry->hasWindowFuncs)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-		   errmsg("row-level locks are not allowed with window functions")));
+				 /*------
+				   translator: %s is a SQL row locking clause such as FOR UPDATE */
+				 errmsg("%s is not allowed with window functions",
+						LCS_asString(((RowMarkClause *)
+									  linitial(qry->rowMarks))->strength))));
 	if (expression_returns_set((Node *) qry->targetList))
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("row-level locks are not allowed with set-returning functions in the target list")));
+				 /*------
+				   translator: %s is a SQL row locking clause such as FOR UPDATE */
+				 errmsg("%s is not allowed with set-returning functions in the target list",
+						LCS_asString(((RowMarkClause *)
+									  linitial(qry->rowMarks))->strength))));
 }
 
 /*
@@ -2307,7 +2376,10 @@ transformLockingClause(ParseState *pstate, Query *qry, LockingClause *lc,
 			if (thisrel->catalogname || thisrel->schemaname)
 				ereport(ERROR,
 						(errcode(ERRCODE_SYNTAX_ERROR),
-						 errmsg("row-level locks must specify unqualified relation names"),
+						 /*------
+						   translator: %s is a SQL row locking clause such as FOR UPDATE */
+						 errmsg("%s must specify unqualified relation names",
+								LCS_asString(lc->strength)),
 						 parser_errposition(pstate, thisrel->location)));
 
 			i = 0;
@@ -2337,25 +2409,37 @@ transformLockingClause(ParseState *pstate, Query *qry, LockingClause *lc,
 						case RTE_JOIN:
 							ereport(ERROR,
 									(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-									 errmsg("row-level locks cannot be applied to a join"),
+									 /*------
+									   translator: %s is a SQL row locking clause such as FOR UPDATE */
+									 errmsg("%s cannot be applied to a join",
+											LCS_asString(lc->strength)),
 							 parser_errposition(pstate, thisrel->location)));
 							break;
 						case RTE_FUNCTION:
 							ereport(ERROR,
 									(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-									 errmsg("row-level locks cannot be applied to a function"),
+									 /*------
+									   translator: %s is a SQL row locking clause such as FOR UPDATE */
+									 errmsg("%s cannot be applied to a function",
+											LCS_asString(lc->strength)),
 							 parser_errposition(pstate, thisrel->location)));
 							break;
 						case RTE_VALUES:
 							ereport(ERROR,
 									(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-									 errmsg("row-level locks cannot be applied to VALUES"),
+									 /*------
+									   translator: %s is a SQL row locking clause such as FOR UPDATE */
+									 errmsg("%s cannot be applied to VALUES",
+											LCS_asString(lc->strength)),
 							 parser_errposition(pstate, thisrel->location)));
 							break;
 						case RTE_CTE:
 							ereport(ERROR,
 									(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-									 errmsg("row-level locks cannot be applied to a WITH query"),
+									 /*------
+									   translator: %s is a SQL row locking clause such as FOR UPDATE */
+									 errmsg("%s cannot be applied to a WITH query",
+											LCS_asString(lc->strength)),
 							 parser_errposition(pstate, thisrel->location)));
 							break;
 						default:
@@ -2369,8 +2453,11 @@ transformLockingClause(ParseState *pstate, Query *qry, LockingClause *lc,
 			if (rt == NULL)
 				ereport(ERROR,
 						(errcode(ERRCODE_UNDEFINED_TABLE),
-						 errmsg("relation \"%s\" in row-level lock clause not found in FROM clause",
-								thisrel->relname),
+						 /*------
+						   translator: %s is a SQL row locking clause such as FOR UPDATE */
+						 errmsg("relation \"%s\" in %s clause not found in FROM clause",
+								thisrel->relname,
+								LCS_asString(lc->strength)),
 						 parser_errposition(pstate, thisrel->location)));
 		}
 	}

src/include/parser/analyze.h

@@ -36,6 +36,7 @@ extern Query *transformStmt(ParseState *pstate, Node *parseTree);
 
 extern bool analyze_requires_snapshot(Node *parseTree);
 
+extern char *LCS_asString(LockClauseStrength strength);
 extern void CheckSelectLocking(Query *qry);
 extern void applyLockingClause(Query *qry, Index rtindex,
 				   LockClauseStrength strength, bool noWait, bool pushedDown);