- Fix null handling for date columns (see MDEV-6744)

modified:
  storage/connect/ha_connect.cc
  storage/connect/plgdbutl.cpp
  storage/connect/value.cpp
  storage/connect/value.h

storage/connect/ha_connect.cc

@@ -1840,6 +1840,7 @@ int ha_connect::ScanRecord(PGLOBAL g, uchar *buf)
             } // endswitch type
 
           ((DTVAL*)sdvalin)->SetFormat(g, fmt, strlen(fmt));
+          sdvalin->SetNullable(colp->IsNullable());
           fp->val_str(&attribute);
           sdvalin->SetValue_psz(attribute.c_ptr_safe());
           value->SetValue_pval(sdvalin);

storage/connect/plgdbutl.cpp

@@ -730,6 +730,7 @@ int ExtractDate(char *dts, PDTP pdp, int defy, int val[6])
   char *fmt, c, d, e, W[8][12];
   int   i, k, m, numval;
   int   n, y = 30;
+  bool  b = true;           // true for null dates
 
   if (pdp)
     fmt = pdp->InFmt;
@@ -763,7 +764,8 @@ int ExtractDate(char *dts, PDTP pdp, int defy, int val[6])
     m = pdp->Num;
 
   for (i = 0; i < m; i++) {
-    n = *(int*)W[i];
+    if ((n = *(int*)W[i]))
+      b = false;
 
     switch (k = pdp->Index[i]) {
       case 0:
@@ -822,7 +824,7 @@ int ExtractDate(char *dts, PDTP pdp, int defy, int val[6])
     htrc("numval=%d val=(%d,%d,%d,%d,%d,%d)\n",
           numval, val[0], val[1], val[2], val[3], val[4], val[5]); 
 
-  return numval;
+  return (b) ? 0 : numval;
   } // end of ExtractDate
 
 /***********************************************************************/

storage/connect/value.cpp

@@ -2428,9 +2428,11 @@ bool DTVAL::SetValue_char(char *p, int n)
     if (trace > 1)
       htrc(" setting date: '%s' -> %d\n", Sdate, Tval);
 
-    Null = false;
-  } else
+    Null = (Nullable && ndv == 0);
+  } else {
     rc = TYPVAL<int>::SetValue_char(p, n);
+    Null = (Nullable && Tval == 0);
+  } // endif Pdtp
 
   return rc;
   } // end of SetValue
@@ -2453,9 +2455,11 @@ void DTVAL::SetValue_psz(PSZ p)
     if (trace > 1)
       htrc(" setting date: '%s' -> %d\n", Sdate, Tval);
 
-    Null = false;
-  } else
+    Null = (Nullable && ndv == 0);
+  } else {
     TYPVAL<int>::SetValue_psz(p);
+    Null = (Nullable && Tval == 0);
+  } // endif Pdtp
 
   } // end of SetValue
 
@@ -2496,7 +2500,7 @@ char *DTVAL::GetCharString(char *p)
   } else
     sprintf(p, "%d", Tval);
 
-  Null = false;
+//Null = false;                      ??????????????
   return p;
   } // end of GetCharString
 
@@ -2507,24 +2511,29 @@ char *DTVAL::ShowValue(char *buf, int len)
   {
   if (Pdtp) {
     char  *p;
-    size_t m, n = 0;
-    struct tm tm, *ptm = GetGmTime(&tm);
-
-    if (Len < len) {
-      p = buf;
-      m = len;
-    } else {
-      p = Sdate;
-      m = Len + 1;
-    } // endif Len
 
-    if (ptm)
-      n = strftime(p, m, Pdtp->OutFmt, ptm);
+    if (!Null) {
+      size_t m, n = 0;
+      struct tm tm, *ptm = GetGmTime(&tm);
+  
+      if (Len < len) {
+        p = buf;
+        m = len;
+      } else {
+        p = Sdate;
+        m = Len + 1;
+      } // endif Len
+  
+      if (ptm)
+        n = strftime(p, m, Pdtp->OutFmt, ptm);
+  
+      if (!n) {
+        *p = '\0';
+        strncat(p, "Error", m);
+        } // endif n
 
-    if (!n) {
-      *p = '\0';
-      strncat(p, "Error", m);
-      } // endif n
+    } else
+      p = "";                 // DEFAULT VALUE ???
 
     return p;
   } else

storage/connect/value.h

@@ -357,6 +357,7 @@ class DllExport DTVAL : public TYPVAL<int> {
   DTVAL(PGLOBAL g, double f);
 
   // Implementation
+  virtual bool   IsZero(void) {return Null;}
   virtual bool   SetValue_pval(PVAL valp, bool chktype);
   virtual bool   SetValue_char(char *p, int n);
   virtual void   SetValue_psz(PSZ s);