Hi Rowan, On 31/05/2019 18:18, Rowan Collins wrote: > This sounds like a very useful change. As you say in the RFC, these > operators are going to be more and more common for Postgres users now that > they've been defined for JSON types, and users of most other DBMSes will be > completely unaffected.
Thanks, the patch is been sitting on my HD since a few years now. Mostly no one complained about the geometric operators containing a "?", but for JSON I guess it's already a bit too late. > I wonder if there's any way we can gauge the BC impact, specifically this > case: > >> The only exception to that is that Postgres (and possibly other RDMSs) > allows the creation of custom operators: anyone having a custom “??” > operator in use would need to escape it as “????”. > - Are there any standard or public Postgres extensions that define a "??" > operator? e.g. anything published on https://pgxn.org/ I couldn't find anything, but I can try and ask on the postgres mailing lists. > - Are there any other databases supported by PDO that allow custom > operators, or which might have a "??" operator or syntax token? Not that I know of. Researching that hasn't been easy, but it seems that most of the databases use "?" for positional parameters in prepared queries. Any additional help would be appreciated. > If there is a risk of this affecting a reasonable number of people, we > could add a deprecation notice on encountering "??" in any SQL string in > 7.4, and postpone adding the escaping mechanism until 8.0. Nice catch. I thought one couldn't have "??" but it seems the parser currently doesn't allow two consecutive positional parameter question marks and "??" was sent as-is. I'll try doing more research on the topic. > One other thing worth clarifying is the precise circumstances where ?? will > be treated as an escape. Is it only when it's a separate "word" (start/end > of string or surrounded by whitespace)? For instance, would "A ??= B" be > "unescaped" to "A ?= B" or passed through as is? Note that this changes the > scope of the BC break, as well as the usability of the chosen syntax, as > both "?=" and "??=" could be defined as operators. No word boundaries involved. Any occurrence of "??" outside comments will be translated into "?", so that operators containing the "?" ("A ?| B", "A ?& B") can be used. If one had defined both "?=" and "??=", they would need to be escaped in PDO as "??=" and "????=". Cheers -- Matteo Beccati Development & Consulting - http://www.beccati.com/ -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
