Modified the error handling to make it more flexible (#833)

* Made error handling more flexible

* Fixed a minor issue with a test

source/shared/core_sqlsrv.h

@@ -175,7 +175,7 @@ const int SQL_SERVER_MAX_TYPE_SIZE = 0;
 const int SQL_SERVER_MAX_PARAMS = 2100;
 // increase the maximum message length to accommodate for the long error returned for operand type clash
 // or for conversion of a long string
-const int SQL_MAX_ERROR_MESSAGE_LENGTH = SQL_MAX_MESSAGE_LENGTH * 8;
+const int SQL_MAX_ERROR_MESSAGE_LENGTH = SQL_MAX_MESSAGE_LENGTH * 2;
 
 // max size of a date time string when converting from a DateTime object to a string
 const int MAX_DATETIME_STRING_LEN = 256;
@@ -1889,14 +1889,20 @@ namespace core {
         // and return a more helpful message prepended to the ODBC errors if that error occurs
         if( !SQL_SUCCEEDED( r )) {
 
-            SQLCHAR err_msg[SQL_MAX_ERROR_MESSAGE_LENGTH + 1] = {'\0'};
+            SQLCHAR err_msg[SQL_MAX_MESSAGE_LENGTH + 1] = {'\0'};
             SQLSMALLINT len = 0;
             
             SQLRETURN rtemp = ::SQLGetDiagField( stmt->handle_type(), stmt->handle(), 1, SQL_DIAG_MESSAGE_TEXT, 
-                                             err_msg, SQL_MAX_ERROR_MESSAGE_LENGTH, &len );
+                                             err_msg, SQL_MAX_MESSAGE_LENGTH, &len );
 
+            if (rtemp == SQL_SUCCESS_WITH_INFO && len > SQL_MAX_MESSAGE_LENGTH) {
+                // if the error message is this long, then it must not be the mars message 
+                // defined as ODBC_CONNECTION_BUSY_ERROR -- so return here and continue the 
+                // regular error handling
+                return;
+            }
             CHECK_SQL_ERROR_OR_WARNING( rtemp, stmt ) {
-         
+ 
                 throw CoreException();
             }
 

source/shared/core_util.cpp

@@ -265,10 +265,36 @@ bool core_sqlsrv_get_odbc_error( _Inout_ sqlsrv_context& ctx, _In_ int record_nu
             // We need to calculate number of characters
             SQLINTEGER wsqlstate_len = sizeof( wsqlstate ) / sizeof( SQLWCHAR );
             SQLLEN sqlstate_len = 0;
-            convert_string_from_utf16(enc, wsqlstate, wsqlstate_len, (char**)&error->sqlstate, sqlstate_len);
 
+            convert_string_from_utf16(enc, wsqlstate, wsqlstate_len, (char**)&error->sqlstate, sqlstate_len);
+            
             SQLLEN message_len = 0;
-            convert_string_from_utf16(enc, wnative_message, wmessage_len, (char**)&error->native_message, message_len);
+            if (r == SQL_SUCCESS_WITH_INFO && wmessage_len > SQL_MAX_ERROR_MESSAGE_LENGTH) {
+                // note that wmessage_len is the number of characters required for the error message -- 
+                // create a new buffer big enough for this lengthy error message
+                sqlsrv_malloc_auto_ptr<SQLWCHAR> wnative_message_str;
+
+                SQLSMALLINT expected_len = wmessage_len * sizeof(SQLWCHAR);
+                SQLSMALLINT returned_len = 0;
+
+                wnative_message_str = reinterpret_cast<SQLWCHAR*>(sqlsrv_malloc(expected_len));
+                memset(wnative_message_str, '\0', expected_len); 
+
+                SQLRETURN rtemp = ::SQLGetDiagFieldW(h_type, h, record_number, SQL_DIAG_MESSAGE_TEXT, wnative_message_str, wmessage_len, &returned_len);
+                if (!SQL_SUCCEEDED(rtemp) || returned_len != expected_len) {
+                    // something went wrong
+                    return false;
+                }
+
+                convert_string_from_utf16(enc, wnative_message_str, wmessage_len, (char**)&error->native_message, message_len);
+            } else {
+                convert_string_from_utf16(enc, wnative_message, wmessage_len, (char**)&error->native_message, message_len);
+            }
+
+            if (message_len == 0 && error->native_message == NULL) {
+                // something went wrong
+                return false;
+            }
             break;
     }
 

test/functional/sqlsrv/sqlsrv_ae_type_conversion_select.phpt

@@ -29,8 +29,10 @@ function checkErrors(&$convError)
         $convError[0][1] != '8114' and
         $convError[0][1] != '8169') {
         print_r($convError);
-        fatalError("Conversion failed with unexpected error message. i=$i, j=$j, v=$v\n");
-    }
+        return false;
+    } 
+    
+    return true;
 }
                 
 // Build the select queries. We want every combination of types for conversion
@@ -202,7 +204,9 @@ for ($v = 0; $v < sizeof($values); ++$v) {
             if ($stmt == false) {
                 $convError = sqlsrv_errors();
                 
-                checkErrors($convError);
+                if (!checkErrors($convError)) {
+                    fatalError("Conversion failed with unexpected error message. i=$i, j=$j, v=$v\n");
+                }
                 
                 if (AE\isDataEncrypted()) {
                     $stmtAE = sqlsrv_query($conn, $selectQueryAE[$i][$j]);