Date: Thu, 13 Feb 2025 10:51:27 -0600
From: Justin Pryzby <pryzby@telsasoft.com>
To: pgsql-hackers@lists.postgresql.org
Subject: pg17.3 PQescapeIdentifier() ignores len
Message-ID: <Z64jD3u46gObCo1p@pryzbyj2023>
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I found errors in our sql log after upgrading to 17.3.

error_severity | ERROR
message        | schema "rptcache.44e3955c33bb79f55750897da0c5ab1fa2004af1_20250214" does not exist
query          | copy "rptcache.44e3955c33bb79f55750897da0c5ab1fa2004af1_20250214"."44e3955c33bb79f55750897da0c5ab1fa2004af1_20250214" from stdin

The copy command is from pygresql's inserttable(), which does:

    do {
        t = strchr(s, '.');
        if (!t)
            t = s + strlen(s);
        table = PQescapeIdentifier(self->cnx, s, (size_t)(t - s));
        fprintf(stderr, "table %s len %ld => %s\n", s, t-s, table);
        if (bufpt < bufmax)
            bufpt += snprintf(bufpt, (size_t)(bufmax - bufpt), "%s", table);
        PQfreemem(table);
        s = t;
        if (*s && bufpt < bufmax)
            *bufpt++ = *s++;
    } while (*s);

The fprintf suggests that since 5dc1e42b4 PQescapeIdentifier ignores its len.

python3 -c "import pg; db=pg.DB('postgres'); db.inserttable('child.a000000000000', [1])")
table child.a000000000000 len 5 => "child.a000000000000"
table a000000000000 len 13 => "a000000000000"

-- 
Justin