From 0a1e67bab37a7ad9099db5a7836ad64afbeb569d Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 6 Jan 2008 01:03:23 +0000 Subject: [PATCH] A long time ago, Peter pointed out that ruleutils.c didn't dump simple constant ORDER/GROUP BY entries properly: http://archives.postgresql.org/pgsql-hackers/2001-04/msg00457.php The original solution to that was in fact no good, as demonstrated by today's report from Martin Pitt: http://archives.postgresql.org/pgsql-bugs/2008-01/msg00027.php We can't use the column-number-reference format for a constant that is a resjunk targetlist entry, a case that was unfortunately not thought of in the original discussion. What we can do instead (which did not work at the time, but does work in 7.3 and up) is to emit the constant with explicit ::typename decoration, even if it otherwise wouldn't need it. This is sufficient to keep the parser from thinking it's a column number reference, and indeed is probably what the user must have done to get such a thing into the querytree in the first place. --- src/backend/utils/adt/ruleutils.c | 46 +++++++++++++++++++++---------- 1 file changed, 32 insertions(+), 14 deletions(-) diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c index b7c3d50767d..1cb8311e878 100644 --- a/src/backend/utils/adt/ruleutils.c +++ b/src/backend/utils/adt/ruleutils.c @@ -2,7 +2,7 @@ * ruleutils.c - Functions to convert stored expressions/querytrees * back to source text * - * $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.235.2.3 2007/10/13 15:55:49 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.235.2.4 2008/01/06 01:03:23 tgl Exp $ **********************************************************************/ #include "postgres.h" @@ -165,7 +165,8 @@ static void get_oper_expr(OpExpr *expr, deparse_context *context); static void get_func_expr(FuncExpr *expr, deparse_context *context, bool showimplicit); static void get_agg_expr(Aggref *aggref, deparse_context *context); -static void get_const_expr(Const *constval, deparse_context *context); +static void get_const_expr(Const *constval, deparse_context *context, + int showtype); static void get_sublink_expr(SubLink *sublink, deparse_context *context); static void get_from_clause(Query *query, const char *prefix, deparse_context *context); @@ -2349,15 +2350,20 @@ get_rule_sortgroupclause(SortClause *srt, List *tlist, bool force_colno, expr = (Node *) tle->expr; /* - * Use column-number form if requested by caller or if expression is a - * constant --- a constant is ambiguous (and will be misinterpreted by - * findTargetlistEntry()) if we dump it explicitly. + * Use column-number form if requested by caller. Otherwise, if + * expression is a constant, force it to be dumped with an explicit + * cast as decoration --- this is because a simple integer constant + * is ambiguous (and will be misinterpreted by findTargetlistEntry()) + * if we dump it without any decoration. Otherwise, just dump the + * expression normally. */ - if (force_colno || (expr && IsA(expr, Const))) + if (force_colno) { Assert(!tle->resjunk); appendStringInfo(buf, "%d", tle->resno); } + else if (expr && IsA(expr, Const)) + get_const_expr((Const *) expr, context, 1); else get_rule_expr(expr, context, true); @@ -3381,7 +3387,7 @@ get_rule_expr(Node *node, deparse_context *context, break; case T_Const: - get_const_expr((Const *) node, context); + get_const_expr((Const *) node, context, 0); break; case T_Param: @@ -4162,10 +4168,14 @@ get_agg_expr(Aggref *aggref, deparse_context *context) * get_const_expr * * Make a string representation of a Const + * + * showtype can be -1 to never show "::typename" decoration, or +1 to always + * show it, or 0 to show it only if the constant wouldn't be assumed to be + * the right type by default. * ---------- */ static void -get_const_expr(Const *constval, deparse_context *context) +get_const_expr(Const *constval, deparse_context *context, int showtype) { StringInfo buf = context->buf; Oid typoutput; @@ -4181,8 +4191,11 @@ get_const_expr(Const *constval, deparse_context *context) * Always label the type of a NULL constant to prevent misdecisions * about type when reparsing. */ - appendStringInfo(buf, "NULL::%s", - format_type_with_typemod(constval->consttype, -1)); + appendStringInfo(buf, "NULL"); + if (showtype >= 0) + appendStringInfo(buf, "::%s", + format_type_with_typemod(constval->consttype, + -1)); return; } @@ -4255,10 +4268,15 @@ get_const_expr(Const *constval, deparse_context *context) pfree(extval); + if (showtype < 0) + return; + /* - * Append ::typename unless the constant will be implicitly typed as the - * right type when it is read in. XXX this code has to be kept in sync - * with the behavior of the parser, especially make_const. + * For showtype == 0, append ::typename unless the constant will be + * implicitly typed as the right type when it is read in. + * + * XXX this code has to be kept in sync with the behavior of the parser, + * especially make_const. */ switch (constval->consttype) { @@ -4276,7 +4294,7 @@ get_const_expr(Const *constval, deparse_context *context) needlabel = true; break; } - if (needlabel) + if (needlabel || showtype > 0) appendStringInfo(buf, "::%s", format_type_with_typemod(constval->consttype, -1)); }