Tweak parse location assignment for CURRENT_DATE and related constructs.

All these constructs generate parse trees consisting of a Const and
a run-time type coercion (perhaps a FuncExpr or a CoerceViaIO).  Modify
the raw parse output so that we end up with the original token's location
attached to the type coercion node while the Const has location -1;
before, it was the other way around.  This makes no difference in terms
of what exprLocation() will say about the parse tree as a whole, so it
should not have any user-visible impact.  The point of changing it is that
we do not want contrib/pg_stat_statements to treat these constructs as
replaceable constants.  It will do the right thing if the Const has
location -1 rather than a valid location.

This is a pretty ugly hack, but then this code is ugly already; we should
someday replace this translation with special-purpose parse node(s) that
would allow ruleutils.c to reconstruct the original query text.

(See also commit 5d3fcc4c2e137417ef470d604fee5e452b22f6a7, which also
hacked location assignment rules for the benefit of pg_stat_statements.)

Back-patch to 9.2 where pg_stat_statements grew the ability to recognize
replaceable constants.

Kyotaro Horiguchi

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 0e8cd30326e15fc89f14e188e07ed3cbe45c746b..383008fc56f9ad45adec2adecd1142d9d5e47843 100644 (file)
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -10851,10 +10851,15 @@ func_expr:    func_name '(' ')' over_clause
                                         * of type-input conversion functions.  (As of PG 7.3
                                         * that is actually possible, but not clear that we want
                                         * to rely on it.)
+                                        *
+                                        * The token location is attached to the run-time
+                                        * typecast, not to the Const, for the convenience of
+                                        * pg_stat_statements (which doesn't want these constructs
+                                        * to appear to be replaceable constants).
                                         */
                                        Node *n;
-                                       n = makeStringConstCast("now", @1, SystemTypeName("text"));
-                                       $$ = makeTypeCast(n, SystemTypeName("date"), -1);
+                                       n = makeStringConstCast("now", -1, SystemTypeName("text"));
+                                       $$ = makeTypeCast(n, SystemTypeName("date"), @1);
                                }
                        | CURRENT_TIME
                                {
@@ -10863,8 +10868,8 @@ func_expr:      func_name '(' ')' over_clause
                                         * See comments for CURRENT_DATE.
                                         */
                                        Node *n;
-                                       n = makeStringConstCast("now", @1, SystemTypeName("text"));
-                                       $$ = makeTypeCast(n, SystemTypeName("timetz"), -1);
+                                       n = makeStringConstCast("now", -1, SystemTypeName("text"));
+                                       $$ = makeTypeCast(n, SystemTypeName("timetz"), @1);
                                }
                        | CURRENT_TIME '(' Iconst ')'
                                {
@@ -10874,10 +10879,10 @@ func_expr:    func_name '(' ')' over_clause
                                         */
                                        Node *n;
                                        TypeName *d;
-                                       n = makeStringConstCast("now", @1, SystemTypeName("text"));
+                                       n = makeStringConstCast("now", -1, SystemTypeName("text"));
                                        d = SystemTypeName("timetz");
                                        d->typmods = list_make1(makeIntConst($3, @3));
-                                       $$ = makeTypeCast(n, d, -1);
+                                       $$ = makeTypeCast(n, d, @1);
                                }
                        | CURRENT_TIMESTAMP
                                {
@@ -10904,10 +10909,10 @@ func_expr:    func_name '(' ')' over_clause
                                         */
                                        Node *n;
                                        TypeName *d;
-                                       n = makeStringConstCast("now", @1, SystemTypeName("text"));
+                                       n = makeStringConstCast("now", -1, SystemTypeName("text"));
                                        d = SystemTypeName("timestamptz");
                                        d->typmods = list_make1(makeIntConst($3, @3));
-                                       $$ = makeTypeCast(n, d, -1);
+                                       $$ = makeTypeCast(n, d, @1);
                                }
                        | LOCALTIME
                                {
@@ -10916,8 +10921,8 @@ func_expr:      func_name '(' ')' over_clause
                                         * See comments for CURRENT_DATE.
                                         */
                                        Node *n;
-                                       n = makeStringConstCast("now", @1, SystemTypeName("text"));
-                                       $$ = makeTypeCast((Node *)n, SystemTypeName("time"), -1);
+                                       n = makeStringConstCast("now", -1, SystemTypeName("text"));
+                                       $$ = makeTypeCast((Node *)n, SystemTypeName("time"), @1);
                                }
                        | LOCALTIME '(' Iconst ')'
                                {
@@ -10927,10 +10932,10 @@ func_expr:    func_name '(' ')' over_clause
                                         */
                                        Node *n;
                                        TypeName *d;
-                                       n = makeStringConstCast("now", @1, SystemTypeName("text"));
+                                       n = makeStringConstCast("now", -1, SystemTypeName("text"));
                                        d = SystemTypeName("time");
                                        d->typmods = list_make1(makeIntConst($3, @3));
-                                       $$ = makeTypeCast((Node *)n, d, -1);
+                                       $$ = makeTypeCast((Node *)n, d, @1);
                                }
                        | LOCALTIMESTAMP
                                {
@@ -10939,8 +10944,8 @@ func_expr:      func_name '(' ')' over_clause
                                         * See comments for CURRENT_DATE.
                                         */
                                        Node *n;
-                                       n = makeStringConstCast("now", @1, SystemTypeName("text"));
-                                       $$ = makeTypeCast(n, SystemTypeName("timestamp"), -1);
+                                       n = makeStringConstCast("now", -1, SystemTypeName("text"));
+                                       $$ = makeTypeCast(n, SystemTypeName("timestamp"), @1);
                                }
                        | LOCALTIMESTAMP '(' Iconst ')'
                                {
@@ -10950,10 +10955,10 @@ func_expr:    func_name '(' ')' over_clause
                                         */
                                        Node *n;
                                        TypeName *d;
-                                       n = makeStringConstCast("now", @1, SystemTypeName("text"));
+                                       n = makeStringConstCast("now", -1, SystemTypeName("text"));
                                        d = SystemTypeName("timestamp");
                                        d->typmods = list_make1(makeIntConst($3, @3));
-                                       $$ = makeTypeCast(n, d, -1);
+                                       $$ = makeTypeCast(n, d, @1);
                                }
                        | CURRENT_ROLE
                                {