On Tue, May 24, 2016 at 3:57 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
"David G. Johnston" <david.g.johnston@gmail.com> writes: > I just noticed this comment in scan.l: > /* > * GUC variables. This is a DIRECT violation of the warning given at the > * head of gram.y, ie flex/bison code must not depend on any GUC variables; > * as such, changing their values can induce very unintuitive behavior. > * But we shall have to live with it as a short-term thing until the switch > * to SQL-standard string syntax is complete. > */ > int backslash_quote = BACKSLASH_QUOTE_SAFE_ENCODING; > bool escape_string_warning = true; > bool standard_conforming_strings = true;
> I'm not exactly sure what else needs to happen to remove these forbidden > GUCs and if we are not prepared to do this now when will we ever be...
Dunno, are you prepared to bet that nobody is turning off standard_conforming_strings anymore?
In any case, we keep adding new violations of this rule (cf operator_precedence_warning) so I have little hope that it will ever be completely clean.
I tend to hold the same position. I'd probably update the last sentence of the comment to reflect that reality.
"We use them here due to the user-facing capability to change the parsing rules of SQL-standard string literals."
The switch is not likely to ever be "complete" and if so not likely in whatever period the future reader might consider "short-term".
FWIW I'm not intending to dig any deeper in this area of the codebase. I was actually trying to find "gram.y" via a GitHub search (OT - I'm finding that to be not the most usable tool...need to get better at git cli) and ended up seeing scan.l
so I figured I'd read a few lines and got hit with that. I was trying to formulate an opinion of the "USING opclass" thread...decided that I'd take a pass on that at this time.