data: Let CONCAT return NULL if any of its operands is NULL.

This mimics behavior in SQL and also allows for missing values to be reported
as NULL and propagate that information.

diff --git a/src/core/data.c b/src/core/data.c
index 557dfd6a5fb3011d276c22ccb31442edaaf59ff1..4840736896f55a03b4cf0716e18e3dec7cb9baec 100644 (file)
--- a/src/core/data.c
+++ b/src/core/data.c
@@ -200,20 +200,21 @@ data_concat(const sdb_data_t *d1, const sdb_data_t *d2, sdb_data_t *res)
        else
                return -1;
 
-       if (s1 || s2) {
+       if (s1 && s2) {
                new = malloc(len1 + len2 + 1);
                if (! new)
                        return -1;
-       }
-       else
-               new = NULL;
 
-       if (len1)
-               memcpy(new, s1, len1);
-       if (len2)
-               memcpy(new + len1, s2, len2);
-       if (new)
+               if (len1)
+                       memcpy(new, s1, len1);
+               if (len2)
+                       memcpy(new + len1, s2, len2);
                new[len1 + len2] = '\0';
+       }
+       else {
+               len1 = len2 = 0;
+               new = NULL;
+       }
 
        res->type = d1->type;
        if (res->type == SDB_TYPE_STRING) {

diff --git a/t/unit/core/data_test.c b/t/unit/core/data_test.c
index a1b4caa59965c7b307dcf848d40f0011ea4ea1b8..2336c5e98d335714f510797c31f745126bb938ee 100644 (file)
--- a/t/unit/core/data_test.c
+++ b/t/unit/core/data_test.c
@@ -694,7 +694,7 @@ START_TEST(test_expr_eval)
                        SDB_DATA_INIT,
                        SDB_DATA_INIT,
                        SDB_DATA_INIT,
-                       { SDB_TYPE_STRING, { .string = "" } },
+                       { SDB_TYPE_STRING, { .string = NULL } },
                },
                {
                        { SDB_TYPE_STRING, { .string = NULL } },
@@ -714,7 +714,7 @@ START_TEST(test_expr_eval)
                        SDB_DATA_INIT,
                        SDB_DATA_INIT,
                        SDB_DATA_INIT,
-                       { SDB_TYPE_STRING, { .string = "" } },
+                       { SDB_TYPE_STRING, { .string = NULL } },
                },
                {
                        { SDB_TYPE_STRING, { .string = "a" } },
@@ -744,7 +744,7 @@ START_TEST(test_expr_eval)
                        SDB_DATA_INIT,
                        SDB_DATA_INIT,
                        SDB_DATA_INIT,
-                       { SDB_TYPE_BINARY, { .binary = { 1, (unsigned char *)"a" } } },
+                       { SDB_TYPE_BINARY, { .binary = { 0, NULL } } },
                },
                {
                        { SDB_TYPE_BINARY, { .binary = { 0, NULL } } },
@@ -764,7 +764,7 @@ START_TEST(test_expr_eval)
                        SDB_DATA_INIT,
                        SDB_DATA_INIT,
                        SDB_DATA_INIT,
-                       { SDB_TYPE_BINARY, { .binary = { 1, (unsigned char *)"a" } } },
+                       { SDB_TYPE_BINARY, { .binary = { 0, NULL } } },
                },
                {
                        {