Re: fmtId() and pg_dump

Interesting idea.  Not sure how you are going to do that since
appendPQExpBuffer uses vsnprintf.  Would you spin through the format
string and modify the pointers sent to vsnprintf?  Seems like a lot of
work.

FYI, the 7.2 code had fmtId called pretty messed up in certain places
but I think I fixed them all.

---------------------------------------------------------------------------

Neil Conway wrote:
> The fmtId() function used in pg_dump for optional quoting identifiers
> has bothered me for a while now. The API is confusing: the returned
> value needs to be used before fmtId() is called again, because the
> buffer the return value points to is re-used for each call of fmtId().
> That leads to bugs for those unaware of this requirement, and clumsy
> code for those that are -- for example (pg_dump.c:2911)
> 
>     appendPQExpBuffer(delq, "DROP TYPE %s.",
>                       fmtId(tinfo->typnamespace->nspname,
>                             force_quotes));
>     appendPQExpBuffer(delq, "%s;\n",
>                       fmtId(tinfo->typname, force_quotes));
> 
> Should really only be 1 line of code. Similar ugliness occurs in many
> places (e.g. several lines down, there is a section of 4 calls to
> appendPQExpBuffer() that could be condensed down to 1, if not for
> fmtId() ).
> 
> Lastly, it has a tendancy to produce memory leaks -- for example,
> convertRegProcReference() in pg_dump.c will leak memory when used
> with PostgreSQL >= 7.3. When I mentioned this to Tom Lane, he
> said that he didn't see a way to fix it without convoluting the
> code, and suggested I bring it up on -hackers.
> 
> My suggestion is: since fmtId() is almost always used with
> appendPQExpBuffer(), we should add a wrapper function to pg_dump
> that accepts an extra escape sequence (%S, or %i, perhaps), which
> would properly quote the input string before passing it to
> appendPQExpBuffer(). That should ensure that there won't be any
> leaks from adding quotes to identifiers, but also allow us to avoid
> playing games with static buffers, like fmtId() does now.
> 
> Any comments?
> 
> Cheers,
> 
> Neil
> 
> -- 
> Neil Conway <neilconway@rogers.com>
> PGP Key ID: DB3C29FC
> 
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