A trailing garbage character is accepted after a special date/time expression

[ChudaykinAlex]

A single character following NOW, TODAY, TOMORROW or YESTERDAY is silently ignored instead of raising a conversion error:

SELECT CAST('NOW)' AS TIMESTAMP) FROM RDB$DATABASE;      -- succeeds, returns the current timestamp
SELECT CAST('TODAY!' AS DATE) FROM RDB$DATABASE;         -- succeeds, returns the current date
SELECT CAST('YESTERDAY-' AS DATE) FROM RDB$DATABASE;     -- succeeds, returns yesterday

Two or more garbage characters are rejected correctly, so only the first one slips through:

SELECT CAST('NOW))' AS TIMESTAMP) FROM RDB$DATABASE;     -- conversion error, as expected

The effect was confirmed in master, v5.0-release, B3_0_Release.

Cause

CVT_string_to_datetime() in src/common/cvt.cpp validates the rest of the string after the word has been read:

while (++p < end)
{
    if (*p != ' ' && *p != '\t' && *p != '\0')
        CVT_conversion_error(desc, cb->err);
}

At this point p already points to the first character that was not consumed as a part of the word, so the pre-increment in the condition skips it and it is never checked.

Fix

while (p < end)
{
    if (*p != ' ' && *p != '\t' && *p != '\0')
        CVT_conversion_error(desc, cb->err);

    ++p;
}

Trailing blanks, tabs and NULs stay allowed, so CHAR padding keeps working.

Tested on master, B3_0_Release