Implement parser hooks for processing ColumnRef and ParamRef nodes, as per my

recent proposal.  As proof of concept, remove knowledge of Params from the
core parser, arranging for them to be handled entirely by parser hook
functions.  It turns out we need an additional hook for that --- I had
forgotten about the code that handles inferring a parameter's type from
context.

This is a preliminary step towards letting plpgsql handle its variables
through parser hooks.  Additional work remains to be done to expose the
facility through SPI, but I think this is all the changes needed in the core
parser.

src/backend/catalog/namespace.c

@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/namespace.c,v 1.119 2009/10/08 02:39:17 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/namespace.c,v 1.120 2009/10/31 01:41:31 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2289,6 +2289,38 @@ DeconstructQualifiedName(List *names,
 	*objname_p = objname;
 }
 
+/*
+ * LookupNamespaceNoError
+ *		Look up a schema name.
+ *
+ * Returns the namespace OID, or InvalidOid if not found.
+ *
+ * Note this does NOT perform any permissions check --- callers are
+ * responsible for being sure that an appropriate check is made.
+ * In the majority of cases LookupExplicitNamespace is preferable.
+ */
+Oid
+LookupNamespaceNoError(const char *nspname)
+{
+	/* check for pg_temp alias */
+	if (strcmp(nspname, "pg_temp") == 0)
+	{
+		if (OidIsValid(myTempNamespace))
+			return myTempNamespace;
+
+		/*
+		 * Since this is used only for looking up existing objects, there is
+		 * no point in trying to initialize the temp namespace here; and doing
+		 * so might create problems for some callers. Just report "not found".
+		 */
+		return InvalidOid;
+	}
+
+	return GetSysCacheOid(NAMESPACENAME,
+						  CStringGetDatum(nspname),
+						  0, 0, 0);
+}
+
 /*
  * LookupExplicitNamespace
  *		Process an explicitly-specified schema name: look up the schema
@@ -2336,8 +2368,8 @@ LookupExplicitNamespace(const char *nspname)
  * LookupCreationNamespace
  *		Look up the schema and verify we have CREATE rights on it.
  *
- * This is just like LookupExplicitNamespace except for the permission check,
- * and that we are willing to create pg_temp if needed.
+ * This is just like LookupExplicitNamespace except for the different
+ * permission check, and that we are willing to create pg_temp if needed.
  *
  * Note: calling this may result in a CommandCounterIncrement operation,
  * if we have to create or clean out the temp namespace.

src/backend/parser/Makefile

@@ -2,7 +2,7 @@
 #
 # Makefile for parser
 #
-# $PostgreSQL: pgsql/src/backend/parser/Makefile,v 1.51 2009/08/28 20:26:19 petere Exp $
+# $PostgreSQL: pgsql/src/backend/parser/Makefile,v 1.52 2009/10/31 01:41:31 tgl Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -12,9 +12,10 @@ include $(top_builddir)/src/Makefile.global
 
 override CPPFLAGS := -I$(srcdir) $(CPPFLAGS)
 
-OBJS= analyze.o gram.o keywords.o parser.o parse_agg.o parse_cte.o parse_clause.o \
-      parse_expr.o parse_func.o parse_node.o parse_oper.o parse_relation.o \
-      parse_type.o parse_coerce.o parse_target.o parse_utilcmd.o scansup.o kwlookup.o
+OBJS= analyze.o gram.o keywords.o kwlookup.o parser.o \
+      parse_agg.o parse_clause.o parse_coerce.o parse_cte.o parse_expr.o \
+      parse_func.o parse_node.o parse_oper.o parse_param.o parse_relation.o \
+      parse_target.o parse_type.o parse_utilcmd.o scansup.o
 
 FLEXFLAGS = -CF
 

src/backend/parser/README

-$PostgreSQL: pgsql/src/backend/parser/README,v 1.10 2008/04/09 01:00:46 momjian Exp $
+$PostgreSQL: pgsql/src/backend/parser/README,v 1.11 2009/10/31 01:41:31 tgl Exp $
 
 Parser
 ======
@@ -10,17 +10,20 @@ to the optimizer and then executor.
 parser.c	things start here
 scan.l		break query into tokens
 scansup.c	handle escapes in input strings
-keywords.c	turn keywords into specific tokens
-gram.y		parse the tokens and fill query-type-specific structures
+kwlookup.c	turn keywords into specific tokens
+keywords.c	table of standard keywords (passed to kwlookup.c)
+gram.y		parse the tokens and produce a "raw" parse tree
 analyze.c	top level of parse analysis for optimizable queries
+parse_agg.c	handle aggregates, like SUM(col1),  AVG(col2), ...
 parse_clause.c	handle clauses like WHERE, ORDER BY, GROUP BY, ...
 parse_coerce.c	handle coercing expressions to different data types
+parse_cte.c	handle Common Table Expressions (WITH clauses)
 parse_expr.c	handle expressions like col, col + 3, x = 3 or x = 4
-parse_oper.c	handle operators in expressions
-parse_agg.c	handle aggregates, like SUM(col1),  AVG(col2), ...
 parse_func.c	handle functions, table.column and column identifiers
 parse_node.c	create nodes for various structures
-parse_target.c	handle the result list of the query
+parse_oper.c	handle operators in expressions
+parse_param.c	handle Params (for the cases used in the core backend)
 parse_relation.c support routines for tables and column handling
+parse_target.c	handle the result list of the query
 parse_type.c	support routines for data type handling
 parse_utilcmd.c	parse analysis for utility commands (done at execution time)

src/backend/parser/analyze.c

@@ -17,7 +17,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.395 2009/10/28 14:55:43 tgl Exp $
+ *	$PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.396 2009/10/31 01:41:31 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -35,6 +35,7 @@
 #include "parser/parse_coerce.h"
 #include "parser/parse_cte.h"
 #include "parser/parse_oper.h"
+#include "parser/parse_param.h"
 #include "parser/parse_relation.h"
 #include "parser/parse_target.h"
 #include "parser/parsetree.h"
@@ -62,7 +63,6 @@ static Query *transformExplainStmt(ParseState *pstate,
 					 ExplainStmt *stmt);
 static void transformLockingClause(ParseState *pstate, Query *qry,
 								   LockingClause *lc, bool pushedDown);
-static bool check_parameter_resolution_walker(Node *node, ParseState *pstate);
 
 
 /*
@@ -86,9 +86,9 @@ parse_analyze(Node *parseTree, const char *sourceText,
 	Assert(sourceText != NULL); /* required as of 8.4 */
 
 	pstate->p_sourcetext = sourceText;
-	pstate->p_paramtypes = paramTypes;
-	pstate->p_numparams = numParams;
-	pstate->p_variableparams = false;
+
+	if (numParams > 0)
+		parse_fixed_parameters(pstate, paramTypes, numParams);
 
 	query = transformStmt(pstate, parseTree);
 
@@ -114,18 +114,13 @@ parse_analyze_varparams(Node *parseTree, const char *sourceText,
 	Assert(sourceText != NULL); /* required as of 8.4 */
 
 	pstate->p_sourcetext = sourceText;
-	pstate->p_paramtypes = *paramTypes;
-	pstate->p_numparams = *numParams;
-	pstate->p_variableparams = true;
+
+	parse_variable_parameters(pstate, paramTypes, numParams);
 
 	query = transformStmt(pstate, parseTree);
 
 	/* make sure all is well with parameter types */
-	if (pstate->p_numparams > 0)
-		check_parameter_resolution_walker((Node *) query, pstate);
-
-	*paramTypes = pstate->p_paramtypes;
-	*numParams = pstate->p_numparams;
+	check_variable_parameters(pstate, query);
 
 	free_parsestate(pstate);
 
@@ -1982,7 +1977,7 @@ transformDeclareCursorStmt(ParseState *pstate, DeclareCursorStmt *stmt)
  *
  * EXPLAIN is just like other utility statements in that we emit it as a
  * CMD_UTILITY Query node with no transformation of the raw parse tree.
- * However, if p_variableparams is set, it could be that the client is
+ * However, if p_coerce_param_hook is set, it could be that the client is
  * expecting us to resolve parameter types in something like
  *		EXPLAIN SELECT * FROM tab WHERE col = $1
  * To deal with such cases, we run parse analysis and throw away the result;
@@ -1996,7 +1991,7 @@ transformExplainStmt(ParseState *pstate, ExplainStmt *stmt)
 {
 	Query	   *result;
 
-	if (pstate->p_variableparams)
+	if (pstate->p_coerce_param_hook != NULL)
 	{
 		/* Since parse analysis scribbles on its input, copy the tree first! */
 		(void) transformStmt(pstate, copyObject(stmt->query));
@@ -2239,50 +2234,3 @@ applyLockingClause(Query *qry, Index rtindex,
 	rc->pushedDown = pushedDown;
 	qry->rowMarks = lappend(qry->rowMarks, rc);
 }
-
-
-/*
- * Traverse a fully-analyzed tree to verify that parameter symbols
- * match their types.  We need this because some Params might still
- * be UNKNOWN, if there wasn't anything to force their coercion,
- * and yet other instances seen later might have gotten coerced.
- */
-static bool
-check_parameter_resolution_walker(Node *node, ParseState *pstate)
-{
-	if (node == NULL)
-		return false;
-	if (IsA(node, Param))
-	{
-		Param	   *param = (Param *) node;
-
-		if (param->paramkind == PARAM_EXTERN)
-		{
-			int			paramno = param->paramid;
-
-			if (paramno <= 0 || /* shouldn't happen, but... */
-				paramno > pstate->p_numparams)
-				ereport(ERROR,
-						(errcode(ERRCODE_UNDEFINED_PARAMETER),
-						 errmsg("there is no parameter $%d", paramno),
-						 parser_errposition(pstate, param->location)));
-
-			if (param->paramtype != pstate->p_paramtypes[paramno - 1])
-				ereport(ERROR,
-						(errcode(ERRCODE_AMBIGUOUS_PARAMETER),
-					 errmsg("could not determine data type of parameter $%d",
-							paramno),
-						 parser_errposition(pstate, param->location)));
-		}
-		return false;
-	}
-	if (IsA(node, Query))
-	{
-		/* Recurse into RTE subquery or not-yet-planned sublink subquery */
-		return query_tree_walker((Query *) node,
-								 check_parameter_resolution_walker,
-								 (void *) pstate, 0);
-	}
-	return expression_tree_walker(node, check_parameter_resolution_walker,
-								  (void *) pstate);
-}

src/backend/parser/parse_coerce.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_coerce.c,v 2.177 2009/06/11 14:49:00 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_coerce.c,v 2.178 2009/10/31 01:41:31 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -259,69 +259,21 @@ coerce_type(ParseState *pstate, Node *node,
 
 		return result;
 	}
-	if (inputTypeId == UNKNOWNOID && IsA(node, Param) &&
-		((Param *) node)->paramkind == PARAM_EXTERN &&
-		pstate != NULL && pstate->p_variableparams)
+	if (IsA(node, Param) &&
+		pstate != NULL && pstate->p_coerce_param_hook != NULL)
 	{
 		/*
-		 * Input is a Param of previously undetermined type, and we want to
-		 * update our knowledge of the Param's type.  Find the topmost
-		 * ParseState and update the state.
+		 * Allow the CoerceParamHook to decide what happens.  It can return
+		 * a transformed node (very possibly the same Param node), or return
+		 * NULL to indicate we should proceed with normal coercion.
 		 */
-		Param	   *param = (Param *) node;
-		int			paramno = param->paramid;
-		ParseState *toppstate;
-
-		toppstate = pstate;
-		while (toppstate->parentParseState != NULL)
-			toppstate = toppstate->parentParseState;
-
-		if (paramno <= 0 ||		/* shouldn't happen, but... */
-			paramno > toppstate->p_numparams)
-			ereport(ERROR,
-					(errcode(ERRCODE_UNDEFINED_PARAMETER),
-					 errmsg("there is no parameter $%d", paramno),
-					 parser_errposition(pstate, param->location)));
-
-		if (toppstate->p_paramtypes[paramno - 1] == UNKNOWNOID)
-		{
-			/* We've successfully resolved the type */
-			toppstate->p_paramtypes[paramno - 1] = targetTypeId;
-		}
-		else if (toppstate->p_paramtypes[paramno - 1] == targetTypeId)
-		{
-			/* We previously resolved the type, and it matches */
-		}
-		else
-		{
-			/* Ooops */
-			ereport(ERROR,
-					(errcode(ERRCODE_AMBIGUOUS_PARAMETER),
-					 errmsg("inconsistent types deduced for parameter $%d",
-							paramno),
-					 errdetail("%s versus %s",
-						format_type_be(toppstate->p_paramtypes[paramno - 1]),
-							   format_type_be(targetTypeId)),
-					 parser_errposition(pstate, param->location)));
-		}
-
-		param->paramtype = targetTypeId;
-
-		/*
-		 * Note: it is tempting here to set the Param's paramtypmod to
-		 * targetTypeMod, but that is probably unwise because we have no
-		 * infrastructure that enforces that the value delivered for a Param
-		 * will match any particular typmod.  Leaving it -1 ensures that a
-		 * run-time length check/coercion will occur if needed.
-		 */
-		param->paramtypmod = -1;
-
-		/* Use the leftmost of the param's and coercion's locations */
-		if (location >= 0 &&
-			(param->location < 0 || location < param->location))
-			param->location = location;
-
-		return (Node *) param;
+		result = (*pstate->p_coerce_param_hook) (pstate,
+												 (Param *) node,
+												 targetTypeId,
+												 targetTypeMod,
+												 location);
+		if (result)
+			return result;
 	}
 	pathtype = find_coercion_pathway(targetTypeId, inputTypeId, ccontext,
 									 &funcId);

src/backend/parser/parse_func.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_func.c,v 1.217 2009/10/08 02:39:23 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_func.c,v 1.218 2009/10/31 01:41:31 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -33,8 +33,6 @@
 static Oid	FuncNameAsType(List *funcname);
 static Node *ParseComplexProjection(ParseState *pstate, char *funcname,
 					   Node *first_arg, int location);
-static void unknown_attribute(ParseState *pstate, Node *relref, char *attname,
-				  int location);
 
 
 /*
@@ -53,6 +51,8 @@ static void unknown_attribute(ParseState *pstate, Node *relref, char *attname,
  *	not to affect the semantics.  When is_column is true, we should have
  *	a single argument (the putative table), unqualified function name
  *	equal to the column name, and no aggregate or variadic decoration.
+ *	Also, when is_column is true, we return NULL on failure rather than
+ *	reporting a no-such-function error.
  *
  *	The argument expressions (in fargs) must have been transformed already.
  */
@@ -253,16 +253,11 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 		/*
 		 * Oops.  Time to die.
 		 *
-		 * If we are dealing with the attribute notation rel.function, give an
-		 * error message that is appropriate for that case.
+		 * If we are dealing with the attribute notation rel.function,
+		 * let the caller handle failure.
 		 */
 		if (is_column)
-		{
-			Assert(nargs == 1);
-			Assert(list_length(funcname) == 1);
-			unknown_attribute(pstate, first_arg, strVal(linitial(funcname)),
-							  location);
-		}
+			return NULL;
 
 		/*
 		 * Else generate a detailed complaint for a function
@@ -1343,55 +1338,6 @@ ParseComplexProjection(ParseState *pstate, char *funcname, Node *first_arg,
 	return NULL;				/* funcname does not match any column */
 }
 
-/*
- * helper routine for delivering "column does not exist" error message
- */
-static void
-unknown_attribute(ParseState *pstate, Node *relref, char *attname,
-				  int location)
-{
-	RangeTblEntry *rte;
-
-	if (IsA(relref, Var) &&
-		((Var *) relref)->varattno == InvalidAttrNumber)
-	{
-		/* Reference the RTE by alias not by actual table name */
-		rte = GetRTEByRangeTablePosn(pstate,
-									 ((Var *) relref)->varno,
-									 ((Var *) relref)->varlevelsup);
-		ereport(ERROR,
-				(errcode(ERRCODE_UNDEFINED_COLUMN),
-				 errmsg("column %s.%s does not exist",
-						rte->eref->aliasname, attname),
-				 parser_errposition(pstate, location)));
-	}
-	else
-	{
-		/* Have to do it by reference to the type of the expression */
-		Oid			relTypeId = exprType(relref);
-
-		if (ISCOMPLEX(relTypeId))
-			ereport(ERROR,
-					(errcode(ERRCODE_UNDEFINED_COLUMN),
-					 errmsg("column \"%s\" not found in data type %s",
-							attname, format_type_be(relTypeId)),
-					 parser_errposition(pstate, location)));
-		else if (relTypeId == RECORDOID)
-			ereport(ERROR,
-					(errcode(ERRCODE_UNDEFINED_COLUMN),
-			   errmsg("could not identify column \"%s\" in record data type",
-					  attname),
-					 parser_errposition(pstate, location)));
-		else
-			ereport(ERROR,
-					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-					 errmsg("column notation .%s applied to type %s, "
-							"which is not a composite type",
-							attname, format_type_be(relTypeId)),
-					 parser_errposition(pstate, location)));
-	}
-}
-
 /*
  * funcname_signature_string
  *		Build a string representing a function name, including arg types.

src/backend/parser/parse_node.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_node.c,v 1.105 2009/06/11 14:49:00 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_node.c,v 1.106 2009/10/31 01:41:31 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,7 +53,12 @@ make_parsestate(ParseState *parentParseState)
 	if (parentParseState)
 	{
 		pstate->p_sourcetext = parentParseState->p_sourcetext;
-		pstate->p_variableparams = parentParseState->p_variableparams;
+		/* all hooks are copied from parent */
+		pstate->p_pre_columnref_hook = parentParseState->p_pre_columnref_hook;
+		pstate->p_post_columnref_hook = parentParseState->p_post_columnref_hook;
+		pstate->p_paramref_hook = parentParseState->p_paramref_hook;
+		pstate->p_coerce_param_hook = parentParseState->p_coerce_param_hook;
+		pstate->p_ref_hook_state = parentParseState->p_ref_hook_state;
 	}
 
 	return pstate;

src/backend/parser/parse_param.c

+/*-------------------------------------------------------------------------
+ *
+ * parse_param.c
+ *	  handle parameters in parser
+ *
+ * This code covers two cases that are used within the core backend:
+ *		* a fixed list of parameters with known types
+ *		* an expandable list of parameters whose types can optionally
+ *		  be determined from context
+ * In both cases, only explicit $n references (ParamRef nodes) are supported.
+ *
+ * Note that other approaches to parameters are possible using the parser
+ * hooks defined in ParseState.
+ *
+ * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_param.c,v 2.1 2009/10/31 01:41:31 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include <limits.h>
+
+#include "catalog/pg_type.h"
+#include "nodes/nodeFuncs.h"
+#include "parser/parse_param.h"
+#include "utils/builtins.h"
+
+
+typedef struct FixedParamState
+{
+	Oid		   *paramTypes;		/* array of parameter type OIDs */
+	int			numParams;		/* number of array entries */
+} FixedParamState;
+
+/*
+ * In the varparams case, the caller-supplied OID array (if any) can be
+ * re-palloc'd larger at need.  A zero array entry means that parameter number
+ * hasn't been seen, while UNKNOWNOID means the parameter has been used but
+ * its type is not yet known.
+ */
+typedef struct VarParamState
+{
+	Oid		  **paramTypes;		/* array of parameter type OIDs */
+	int		   *numParams;		/* number of array entries */
+} VarParamState;
+
+static Node *fixed_paramref_hook(ParseState *pstate, ParamRef *pref);
+static Node *variable_paramref_hook(ParseState *pstate, ParamRef *pref);
+static Node *variable_coerce_param_hook(ParseState *pstate, Param *param,
+										Oid targetTypeId, int32 targetTypeMod,
+										int location);
+static bool check_parameter_resolution_walker(Node *node, ParseState *pstate);
+
+
+/*
+ * Set up to process a query containing references to fixed parameters.
+ */
+void
+parse_fixed_parameters(ParseState *pstate,
+					   Oid *paramTypes, int numParams)
+{
+	FixedParamState *parstate = palloc(sizeof(FixedParamState));
+
+	parstate->paramTypes = paramTypes;
+	parstate->numParams = numParams;
+	pstate->p_ref_hook_state = (void *) parstate;
+	pstate->p_paramref_hook = fixed_paramref_hook;
+	/* no need to use p_coerce_param_hook */
+}
+
+/*
+ * Set up to process a query containing references to variable parameters.
+ */
+void
+parse_variable_parameters(ParseState *pstate,
+						  Oid **paramTypes, int *numParams)
+{
+	VarParamState *parstate = palloc(sizeof(VarParamState));
+
+	parstate->paramTypes = paramTypes;
+	parstate->numParams = numParams;
+	pstate->p_ref_hook_state = (void *) parstate;
+	pstate->p_paramref_hook = variable_paramref_hook;
+	pstate->p_coerce_param_hook = variable_coerce_param_hook;
+}
+
+/*
+ * Transform a ParamRef using fixed parameter types.
+ */
+static Node *
+fixed_paramref_hook(ParseState *pstate, ParamRef *pref)
+{
+	FixedParamState *parstate = (FixedParamState *) pstate->p_ref_hook_state;
+	int			paramno = pref->number;
+	Param	   *param;
+
+	/* Check parameter number is in range */
+	if (paramno <= 0 || paramno > parstate->numParams)
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_PARAMETER),
+				 errmsg("there is no parameter $%d", paramno),
+				 parser_errposition(pstate, pref->location)));
+
+	param = makeNode(Param);
+	param->paramkind = PARAM_EXTERN;
+	param->paramid = paramno;
+	param->paramtype = parstate->paramTypes[paramno - 1];
+	param->paramtypmod = -1;
+	param->location = pref->location;
+
+	return (Node *) param;
+}
+
+/*
+ * Transform a ParamRef using variable parameter types.
+ *
+ * The only difference here is we must enlarge the parameter type array
+ * as needed.
+ */
+static Node *
+variable_paramref_hook(ParseState *pstate, ParamRef *pref)
+{
+	VarParamState *parstate = (VarParamState *) pstate->p_ref_hook_state;
+	int			paramno = pref->number;
+	Oid		   *pptype;
+	Param	   *param;
+
+	/* Check parameter number is in range */
+	if (paramno <= 0 || paramno > INT_MAX / sizeof(Oid))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_PARAMETER),
+				 errmsg("there is no parameter $%d", paramno),
+				 parser_errposition(pstate, pref->location)));
+	if (paramno > *parstate->numParams)
+	{
+		/* Need to enlarge param array */
+		if (*parstate->paramTypes)
+			*parstate->paramTypes = (Oid *) repalloc(*parstate->paramTypes,
+													 paramno * sizeof(Oid));
+		else
+			*parstate->paramTypes = (Oid *) palloc(paramno * sizeof(Oid));
+		/* Zero out the previously-unreferenced slots */
+		MemSet(*parstate->paramTypes + *parstate->numParams,
+			   0,
+			   (paramno - *parstate->numParams) * sizeof(Oid));
+		*parstate->numParams = paramno;
+	}
+
+	/* Locate param's slot in array */
+	pptype = &(*parstate->paramTypes)[paramno - 1];
+
+	/* If not seen before, initialize to UNKNOWN type */
+	if (*pptype == InvalidOid)
+		*pptype = UNKNOWNOID;
+
+	param = makeNode(Param);
+	param->paramkind = PARAM_EXTERN;
+	param->paramid = paramno;
+	param->paramtype = *pptype;
+	param->paramtypmod = -1;
+	param->location = pref->location;
+
+	return (Node *) param;
+}
+
+/*
+ * Coerce a Param to a query-requested datatype, in the varparams case.
+ */
+static Node *
+variable_coerce_param_hook(ParseState *pstate, Param *param,
+						   Oid targetTypeId, int32 targetTypeMod,
+						   int location)
+{
+	if (param->paramkind == PARAM_EXTERN && param->paramtype == UNKNOWNOID)
+	{
+		/*
+		 * Input is a Param of previously undetermined type, and we want to
+		 * update our knowledge of the Param's type.
+		 */
+		VarParamState *parstate = (VarParamState *) pstate->p_ref_hook_state;
+		Oid		   *paramTypes = *parstate->paramTypes;
+		int			paramno = param->paramid;
+
+		if (paramno <= 0 ||		/* shouldn't happen, but... */
+			paramno > *parstate->numParams)
+			ereport(ERROR,
+					(errcode(ERRCODE_UNDEFINED_PARAMETER),
+					 errmsg("there is no parameter $%d", paramno),
+					 parser_errposition(pstate, param->location)));
+
+		if (paramTypes[paramno - 1] == UNKNOWNOID)
+		{
+			/* We've successfully resolved the type */
+			paramTypes[paramno - 1] = targetTypeId;
+		}
+		else if (paramTypes[paramno - 1] == targetTypeId)
+		{
+			/* We previously resolved the type, and it matches */
+		}
+		else
+		{
+			/* Ooops */
+			ereport(ERROR,
+					(errcode(ERRCODE_AMBIGUOUS_PARAMETER),
+					 errmsg("inconsistent types deduced for parameter $%d",
+							paramno),
+					 errdetail("%s versus %s",
+							   format_type_be(paramTypes[paramno - 1]),
+							   format_type_be(targetTypeId)),
+					 parser_errposition(pstate, param->location)));
+		}
+
+		param->paramtype = targetTypeId;
+
+		/*
+		 * Note: it is tempting here to set the Param's paramtypmod to
+		 * targetTypeMod, but that is probably unwise because we have no
+		 * infrastructure that enforces that the value delivered for a Param
+		 * will match any particular typmod.  Leaving it -1 ensures that a
+		 * run-time length check/coercion will occur if needed.
+		 */
+		param->paramtypmod = -1;
+
+		/* Use the leftmost of the param's and coercion's locations */
+		if (location >= 0 &&
+			(param->location < 0 || location < param->location))
+			param->location = location;
+
+		return (Node *) param;
+	}
+
+	/* Else signal to proceed with normal coercion */
+	return NULL;
+}
+
+/*
+ * Check for consistent assignment of variable parameters after completion
+ * of parsing with parse_variable_parameters.
+ *
+ * Note: this code intentionally does not check that all parameter positions
+ * were used, nor that all got non-UNKNOWN types assigned.  Caller of parser
+ * should enforce that if it's important.
+ */
+void
+check_variable_parameters(ParseState *pstate, Query *query)
+{
+	VarParamState *parstate = (VarParamState *) pstate->p_ref_hook_state;
+
+	/* If numParams is zero then no Params were generated, so no work */
+	if (*parstate->numParams > 0)
+		(void) query_tree_walker(query,
+								 check_parameter_resolution_walker,
+								 (void *) pstate, 0);
+}
+
+/*
+ * Traverse a fully-analyzed tree to verify that parameter symbols
+ * match their types.  We need this because some Params might still
+ * be UNKNOWN, if there wasn't anything to force their coercion,
+ * and yet other instances seen later might have gotten coerced.
+ */
+static bool
+check_parameter_resolution_walker(Node *node, ParseState *pstate)
+{
+	if (node == NULL)
+		return false;
+	if (IsA(node, Param))
+	{
+		Param	   *param = (Param *) node;
+
+		if (param->paramkind == PARAM_EXTERN)
+		{
+			VarParamState *parstate = (VarParamState *) pstate->p_ref_hook_state;
+			int			paramno = param->paramid;
+
+			if (paramno <= 0 || /* shouldn't happen, but... */
+				paramno > *parstate->numParams)
+				ereport(ERROR,
+						(errcode(ERRCODE_UNDEFINED_PARAMETER),
+						 errmsg("there is no parameter $%d", paramno),
+						 parser_errposition(pstate, param->location)));
+
+			if (param->paramtype != (*parstate->paramTypes)[paramno - 1])
+				ereport(ERROR,
+						(errcode(ERRCODE_AMBIGUOUS_PARAMETER),
+					 errmsg("could not determine data type of parameter $%d",
+							paramno),
+						 parser_errposition(pstate, param->location)));
+		}
+		return false;
+	}
+	if (IsA(node, Query))
+	{
+		/* Recurse into RTE subquery or not-yet-planned sublink subquery */
+		return query_tree_walker((Query *) node,
+								 check_parameter_resolution_walker,
+								 (void *) pstate, 0);
+	}
+	return expression_tree_walker(node, check_parameter_resolution_walker,
+								  (void *) pstate);
+}

src/backend/parser/parse_relation.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.146 2009/10/27 17:11:18 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.147 2009/10/31 01:41:31 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -86,7 +86,17 @@ refnameRangeTblEntry(ParseState *pstate,
 	{
 		Oid			namespaceId;
 
-		namespaceId = LookupExplicitNamespace(schemaname);
+		/*
+		 * We can use LookupNamespaceNoError() here because we are only
+		 * interested in finding existing RTEs.  Checking USAGE permission
+		 * on the schema is unnecessary since it would have already been
+		 * checked when the RTE was made.  Furthermore, we want to report
+		 * "RTE not found", not "no permissions for schema", if the name
+		 * happens to match a schema name the user hasn't got access to.
+		 */
+		namespaceId = LookupNamespaceNoError(schemaname);
+		if (!OidIsValid(relId))
+			return NULL;
 		relId = get_relname_relid(refname, namespaceId);
 		if (!OidIsValid(relId))
 			return NULL;
@@ -555,32 +565,6 @@ colNameToVar(ParseState *pstate, char *colname, bool localonly,
 	return result;
 }
 
-/*
- * qualifiedNameToVar
- *	  Search for a qualified column name: either refname.colname or
- *	  schemaname.relname.colname.
- *
- *	  If found, return the appropriate Var node.
- *	  If not found, return NULL.  If the name proves ambiguous, raise error.
- */
-Node *
-qualifiedNameToVar(ParseState *pstate,
-				   char *schemaname,
-				   char *refname,
-				   char *colname,
-				   int location)
-{
-	RangeTblEntry *rte;
-	int			sublevels_up;
-
-	rte = refnameRangeTblEntry(pstate, schemaname, refname, location,
-							   &sublevels_up);
-	if (rte == NULL)
-		return NULL;
-
-	return scanRTEForColumn(pstate, rte, colname, location);
-}
-
 /*
  * markRTEForSelectPriv
  *	   Mark the specified column of an RTE as requiring SELECT privilege
@@ -2389,7 +2373,8 @@ errorMissingRTE(ParseState *pstate, RangeVar *relation)
 
 	/*
 	 * Check to see if there are any potential matches in the query's
-	 * rangetable.
+	 * rangetable.  (Note: cases involving a bad schema name in the
+	 * RangeVar will throw error immediately here.  That seems OK.)
 	 */
 	rte = searchRangeTable(pstate, relation);
 

src/include/catalog/namespace.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/namespace.h,v 1.60 2009/10/08 02:39:23 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/namespace.h,v 1.61 2009/10/31 01:41:31 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -89,6 +89,7 @@ extern bool TSConfigIsVisible(Oid cfgid);
 extern void DeconstructQualifiedName(List *names,
 						 char **nspname_p,
 						 char **objname_p);
+extern Oid	LookupNamespaceNoError(const char *nspname);
 extern Oid	LookupExplicitNamespace(const char *nspname);
 
 extern Oid	LookupCreationNamespace(const char *nspname);

src/include/parser/parse_node.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/parser/parse_node.h,v 1.65 2009/10/27 17:11:18 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/parser/parse_node.h,v 1.66 2009/10/31 01:41:31 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -17,6 +17,20 @@
 #include "nodes/parsenodes.h"
 #include "utils/relcache.h"
 
+
+/*
+ * Function signatures for parser hooks
+ */
+typedef struct ParseState ParseState;
+
+typedef Node * (*PreParseColumnRefHook) (ParseState *pstate, ColumnRef *cref);
+typedef Node * (*PostParseColumnRefHook) (ParseState *pstate, ColumnRef *cref, Node *var);
+typedef Node * (*ParseParamRefHook) (ParseState *pstate, ParamRef *pref);
+typedef Node * (*CoerceParamHook) (ParseState *pstate, Param *param,
+								   Oid targetTypeId, int32 targetTypeMod,
+								   int location);
+
+
 /*
  * State information used during parse analysis
  *
@@ -68,17 +82,8 @@
  * afterwards (so that any resjunk tlist items needed for the sort/group
  * clauses end up at the end of the query tlist).  A WindowDef's location in
  * this list, counting from 1, is the winref number to use to reference it.
- *
- * p_paramtypes: an array of p_numparams type OIDs for $n parameter symbols
- * (zeroth entry in array corresponds to $1).  If p_variableparams is true, the
- * set of param types is not predetermined; in that case, a zero array entry
- * means that parameter number hasn't been seen, and UNKNOWNOID means the
- * parameter has been used but its type is not yet known.  NOTE: in a stack
- * of ParseStates, only the topmost ParseState contains paramtype info; but
- * we copy the p_variableparams flag down to the child nodes for speed in
- * coerce_type.
  */
-typedef struct ParseState
+struct ParseState
 {
 	struct ParseState *parentParseState;		/* stack link */
 	const char *p_sourcetext;	/* source text, or NULL if not available */
@@ -92,12 +97,9 @@ typedef struct ParseState
 	List	   *p_future_ctes;	/* common table exprs not yet in namespace */
 	CommonTableExpr *p_parent_cte;		/* this query's containing CTE */
 	List	   *p_windowdefs;	/* raw representations of window clauses */
-	Oid		   *p_paramtypes;	/* OIDs of types for $n parameter symbols */
-	int			p_numparams;	/* allocated size of p_paramtypes[] */
 	int			p_next_resno;	/* next targetlist resno to assign */
 	List	   *p_locking_clause;		/* raw FOR UPDATE/FOR SHARE info */
 	Node	   *p_value_substitute;		/* what to replace VALUE with, if any */
-	bool		p_variableparams;
 	bool		p_hasAggs;
 	bool		p_hasWindowFuncs;
 	bool		p_hasSubLinks;
@@ -106,7 +108,17 @@ typedef struct ParseState
 	bool		p_locked_from_parent;
 	Relation	p_target_relation;
 	RangeTblEntry *p_target_rangetblentry;
-} ParseState;
+
+	/*
+	 * Optional hook functions for parser callbacks.  These are null unless
+	 * set up by the caller of make_parsestate.
+	 */
+	PreParseColumnRefHook p_pre_columnref_hook;
+	PostParseColumnRefHook p_post_columnref_hook;
+	ParseParamRefHook p_paramref_hook;
+	CoerceParamHook p_coerce_param_hook;
+	void	   *p_ref_hook_state;	/* common passthrough link for above */
+};
 
 /* Support for parser_errposition_callback function */
 typedef struct ParseCallbackState

src/include/parser/parse_param.h

+/*-------------------------------------------------------------------------
+ *
+ * parse_param.h
+ *	  handle parameters in parser
+ *
+ * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * $PostgreSQL: pgsql/src/include/parser/parse_param.h,v 1.1 2009/10/31 01:41:31 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef PARSE_PARAM_H
+#define PARSE_PARAM_H
+
+#include "parser/parse_node.h"
+
+extern void parse_fixed_parameters(ParseState *pstate,
+								   Oid *paramTypes, int numParams);
+extern void parse_variable_parameters(ParseState *pstate,
+									  Oid **paramTypes, int *numParams);
+extern void check_variable_parameters(ParseState *pstate, Query *query);
+
+#endif   /* PARSE_PARAM_H */

src/include/parser/parse_relation.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/parser/parse_relation.h,v 1.66 2009/10/27 17:11:18 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/parser/parse_relation.h,v 1.67 2009/10/31 01:41:31 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -38,11 +38,6 @@ extern Node *scanRTEForColumn(ParseState *pstate, RangeTblEntry *rte,
 				 char *colname, int location);
 extern Node *colNameToVar(ParseState *pstate, char *colname, bool localonly,
 			 int location);
-extern Node *qualifiedNameToVar(ParseState *pstate,
-				   char *schemaname,
-				   char *refname,
-				   char *colname,
-				   int location);
 extern void markVarForSelectPriv(ParseState *pstate, Var *var,
 					 RangeTblEntry *rte);
 extern Relation parserOpenTable(ParseState *pstate, const RangeVar *relation,