Clean up some bugs in oper_select_candidate(), notably the

last loop which would return the *first* surviving-to-that-point candidate
regardless of which one actually passed the test.  This was producing
such curious results as 'oid % 2' getting translated to 'int2(oid) % 2'.

diff --git a/src/backend/parser/parse_oper.c b/src/backend/parser/parse_oper.c
index 529663b6ce5acae6a00719aadbb44ad0bfe06b95..8f82e58517d748728586d18cc61278eac4a98b9e 100644 (file)
--- a/src/backend/parser/parse_oper.c
+++ b/src/backend/parser/parse_oper.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/parser/parse_oper.c,v 1.30 1999/08/23 23:48:39 tgl Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/parser/parse_oper.c,v 1.31 1999/08/26 04:59:15 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -28,9 +28,7 @@ static Oid *oper_select_candidate(int nargs, Oid *input_typeids,
 static Operator oper_exact(char *op, Oid arg1, Oid arg2);
 static Operator oper_inexact(char *op, Oid arg1, Oid arg2);
 static int binary_oper_get_candidates(char *opname,
-                                                  Oid leftTypeId,
-                                                  Oid rightTypeId,
-                                                  CandidateList *candidates);
+                                                                         CandidateList *candidates);
 static int unary_oper_get_candidates(char *op,
                                                  Oid typeId,
                                                  CandidateList *candidates,
@@ -64,15 +62,12 @@ oprid(Operator op)
 
 
 /* binary_oper_get_candidates()
- *     given opname, leftTypeId and rightTypeId,
- *     find all possible (arg1, arg2) pairs for which an operator named
- *     opname exists, such that leftTypeId can be coerced to arg1 and
- *     rightTypeId can be coerced to arg2
+ *     given opname, find all possible input type pairs for which an operator
+ *     named opname exists.  Build a list of the candidate input types.
+ *     Returns number of candidates found.
  */
 static int
 binary_oper_get_candidates(char *opname,
-                                                  Oid leftTypeId,
-                                                  Oid rightTypeId,
                                                   CandidateList *candidates)
 {
        CandidateList current_candidate;
@@ -224,14 +219,17 @@ oper_select_candidate(int nargs,
                        ncandidates++;
                }
                /* otherwise, don't bother keeping this one... */
-               else
-                       last_candidate->next = NULL;
        }
 
+       if (last_candidate)                     /* terminate rebuilt list */
+               last_candidate->next = NULL;
+
        if (ncandidates <= 1)
        {
-               if (!can_coerce_type(1, &input_typeids[0], &candidates->args[0])
-                || !can_coerce_type(1, &input_typeids[1], &candidates->args[1]))
+               if (ncandidates > 0 &&
+                       (!can_coerce_type(1, &input_typeids[0], &candidates->args[0]) ||
+                        (nargs > 1 &&
+                         !can_coerce_type(1, &input_typeids[1], &candidates->args[1]))))
                        ncandidates = 0;
                return (ncandidates == 1) ? candidates->args : NULL;
        }
@@ -252,9 +250,9 @@ oper_select_candidate(int nargs,
                nmatch = 0;
                for (i = 0; i < nargs; i++)
                {
-                       current_category = TypeCategory(current_typeids[i]);
                        if (input_typeids[i] != UNKNOWNOID)
                        {
+                               current_category = TypeCategory(current_typeids[i]);
                                if (current_typeids[i] == input_typeids[i])
                                        nmatch++;
                                else if (IsPreferredType(current_category, current_typeids[i])
@@ -276,14 +274,17 @@ oper_select_candidate(int nargs,
                        last_candidate = current_candidate;
                        ncandidates++;
                }
-               else
-                       last_candidate->next = NULL;
        }
 
+       if (last_candidate)                     /* terminate rebuilt list */
+               last_candidate->next = NULL;
+
        if (ncandidates <= 1)
        {
-               if (!can_coerce_type(1, &input_typeids[0], &candidates->args[0])
-                       || ((nargs > 1) && !can_coerce_type(1, &input_typeids[1], &candidates->args[1])))
+               if (ncandidates > 0 &&
+                       (!can_coerce_type(1, &input_typeids[0], &candidates->args[0]) ||
+                        (nargs > 1 &&
+                         !can_coerce_type(1, &input_typeids[1], &candidates->args[1]))))
                        ncandidates = 0;
                return (ncandidates == 1) ? candidates->args : NULL;
        }
@@ -309,12 +310,12 @@ oper_select_candidate(int nargs,
                         current_candidate != NULL;
                         current_candidate = current_candidate->next)
                {
+                       current_typeids = current_candidate->args;
                        nmatch = 0;
                        for (i = 0; i < nargs; i++)
                        {
-                               current_typeids = current_candidate->args;
-                               if ((current_type == current_typeids[i])
-                               || IS_BINARY_COMPATIBLE(current_type, current_typeids[i]))
+                               if (current_type == current_typeids[i] ||
+                                       IS_BINARY_COMPATIBLE(current_type, current_typeids[i]))
                                        nmatch++;
                        }
                        if (nmatch == nargs)
@@ -364,16 +365,20 @@ oper_select_candidate(int nargs,
        }
 
        ncandidates = 0;
+       last_candidate = NULL;
        for (current_candidate = candidates;
                 current_candidate != NULL;
                 current_candidate = current_candidate->next)
        {
                if (can_coerce_type(1, &input_typeids[0], &current_candidate->args[0])
                        && can_coerce_type(1, &input_typeids[1], &current_candidate->args[1]))
+               {
                        ncandidates++;
+                       last_candidate = current_candidate;
+               }
        }
 
-       return (ncandidates == 1) ? candidates->args : NULL;
+       return (ncandidates == 1) ? last_candidate->args : NULL;
 }      /* oper_select_candidate() */
 
 
@@ -423,7 +428,7 @@ oper_inexact(char *op, Oid arg1, Oid arg2)
        if (arg1 == InvalidOid)
                arg1 = arg2;
 
-       ncandidates = binary_oper_get_candidates(op, arg1, arg2, &candidates);
+       ncandidates = binary_oper_get_candidates(op, &candidates);
 
        /* No operators found? Then return null... */
        if (ncandidates == 0)