From 5253c518aef4c906dc6c922c51c2d77b0a78bf75 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 20 Feb 2000 06:35:08 +0000
Subject: [PATCH] Fix broken list-slinging logic in func_select_candidate and
agg_select_candidate, which could cause them to keep more candidates than
they should and thus fail to select a single match. I had previously fixed
the identical bug in oper_select_candidate, but didn't realize that the same
error was repeated over here. Also, repair func_select_candidate's curious
notion that it could scribble on the input type-OID vector. That was causing
failure to apply necessary type coercion later on, leading to malfunction of
examples such as select date('now').
---
src/backend/parser/parse_func.c | 66 +++++++++++++++++++++------------
1 file changed, 42 insertions(+), 24 deletions(-)
diff --git a/src/backend/parser/parse_func.c b/src/backend/parser/parse_func.c
index 06afc867903..939d7a91ec3 100644
--- a/src/backend/parser/parse_func.c
+++ b/src/backend/parser/parse_func.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/parser/parse_func.c,v 1.69 2000/02/15 03:37:47 thomas Exp $
+ * $Header: /cvsroot/pgsql/src/backend/parser/parse_func.c,v 1.70 2000/02/20 06:35:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -45,14 +45,13 @@ static Oid **argtype_inherit(int nargs, Oid *oid_array);
static int find_inheritors(Oid relid, Oid **supervec);
static CandidateList func_get_candidates(char *funcname, int nargs);
-static bool
-func_get_detail(char *funcname,
- int nargs,
- Oid *oid_array,
- Oid *funcid, /* return value */
- Oid *rettype, /* return value */
- bool *retset, /* return value */
- Oid **true_typeids);
+static bool func_get_detail(char *funcname,
+ int nargs,
+ Oid *oid_array,
+ Oid *funcid, /* return value */
+ Oid *rettype, /* return value */
+ bool *retset, /* return value */
+ Oid **true_typeids);
static Oid **gen_cross_product(InhPaths *arginh, int nargs);
static void make_arguments(ParseState *pstate,
int nargs,
@@ -228,10 +227,11 @@ agg_select_candidate(Oid typeid, CandidateList candidates)
}
}
/* otherwise, don't bother keeping this one around... */
- else if (last_candidate != NULL)
- last_candidate->next = NULL;
}
+ if (last_candidate) /* terminate rebuilt list */
+ last_candidate->next = NULL;
+
return ((ncandidates == 1) ? candidates->args[0] : 0);
} /* agg_select_candidate() */
@@ -559,8 +559,8 @@ ParseFuncOrColumn(ParseState *pstate, char *funcname, List *fargs,
}
/* Most of the rest of the parser just assumes that functions do not
- * have more than FUNC_MAX_ARGS parameters. We have to test here to protect
- * against array overruns, etc.
+ * have more than FUNC_MAX_ARGS parameters. We have to test here
+ * to protect against array overruns, etc.
*/
if (nargs >= FUNC_MAX_ARGS)
elog(ERROR, "Cannot pass more than %d arguments to a function",
@@ -892,6 +892,7 @@ func_select_candidate(int nargs,
if ((nmatch + nident) == nargs)
return current_candidate->args;
+ /* take this one as the best choice so far? */
if ((nmatch > nbestMatch) || (last_candidate == NULL))
{
nbestMatch = nmatch;
@@ -899,16 +900,19 @@ func_select_candidate(int nargs,
last_candidate = current_candidate;
ncandidates = 1;
}
+ /* no worse than the last choice, so keep this one too? */
else if (nmatch == nbestMatch)
{
last_candidate->next = current_candidate;
last_candidate = current_candidate;
ncandidates++;
}
- else
- last_candidate->next = NULL;
+ /* otherwise, don't bother keeping this one... */
}
+ if (last_candidate) /* terminate rebuilt list */
+ last_candidate->next = NULL;
+
if (ncandidates == 1)
return candidates->args;
@@ -922,6 +926,7 @@ func_select_candidate(int nargs,
{
slot_category = INVALID_TYPE;
slot_type = InvalidOid;
+ last_candidate = NULL;
for (current_candidate = candidates;
current_candidate != NULL;
current_candidate = current_candidate->next)
@@ -935,26 +940,39 @@ func_select_candidate(int nargs,
slot_category = current_category;
slot_type = current_type;
}
- else if ((current_category != slot_category)
- && IS_BUILTIN_TYPE(current_type))
+ else if (current_category != slot_category)
+ {
+ /* punt if more than one category for this slot */
return NULL;
+ }
else if (current_type != slot_type)
{
if (IsPreferredType(slot_category, current_type))
{
slot_type = current_type;
+ /* forget all previous candidates */
candidates = current_candidate;
+ last_candidate = current_candidate;
}
else if (IsPreferredType(slot_category, slot_type))
- candidates->next = current_candidate->next;
+ {
+ /* forget this candidate */
+ if (last_candidate)
+ last_candidate->next = current_candidate->next;
+ else
+ candidates = current_candidate->next;
+ }
+ else
+ last_candidate = current_candidate;
+ }
+ else
+ {
+ /* keep this candidate */
+ last_candidate = current_candidate;
}
}
-
- if (slot_type != InvalidOid)
- input_typeids[i] = slot_type;
- }
- else
- {
+ if (last_candidate) /* terminate rebuilt list */
+ last_candidate->next = NULL;
}
}
--
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