Re: outfuncs.c utility statement support

Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> writes:
> So this seems to be a pretty basic bug. Some node fields of type char
> may be zero, and so printing them as a zero byte just truncates the
> whole output string. This could be fixed by printing chars like strings
> with the full escaping mechanism. See attached patch.

+1 for fixing this, but you have not handled the read side correctly.
pg_strtok doesn't promise to return a null-terminated string, so without
changes, readfuncs.c would not successfully decode a zero-byte char field.
Also it would do the wrong thing for any character code that outToken had
decided to prefix with a backslash. I think you could fix both problems
like this:

/* Read a char field (ie, one ascii character) */
#define READ_CHAR_FIELD(fldname) \
token = pg_strtok(&length); /* skip :fldname */ \
token = pg_strtok(&length); /* get field value */ \
- local_node->fldname = token[0]
+ local_node->fldname = debackslash(token, length)[0]

although that's annoyingly expensive for the normal case where no
special processing is needed. Maybe better

+ local_node->fldname = (length == 0) ? '\0' : (token[0] == '\\') ? token[1] : token[0]

regards, tom lane