The realfail1 and realfail2 backup-prevention rules always returned
token type FCONST, ignoring the possibility that what we've scanned
is more appropriately described as ICONST. I think that at the
time that code was added, it might actually have been safe to not
distinguish; but since we started allowing AS-less aliases in SELECT
target lists, it's definitely legal to have a number immediately
followed by an identifier.
In the SELECT case, it seems there's no visible consequence because
make_const() will change the type back to integer anyway. But I'm
worried that there are other contexts, or will be in future, where
it's more important to get the constant's type right.
Hence, use process_integer_literal to correctly determine which
token type to return.
Arguably this is a bug fix, but given the lack of evidence of
user-visible problems, I'll refrain from back-patching.
Discussion: https://postgr.es/m/21364.1542136808@sss.pgh.pa.us
Make a bunch of basically-cosmetic changes to reduce the diffs between
the flex rules in scan.l, psqlscan.l, and pgc.l. Reorder some code,
adjust a lot of whitespace, sync some comments, make use of flex start
condition scopes to do that.
There are a few non-cosmetic changes in the ECPG lexer:
* Bring over the decimalfail rule (and support function
process_integer_literal) so that ECPG will lex "1..10" into
the same tokens as the backend would. I'm not sure this makes any
visible difference to users, but I'm not sure it doesn't, either.
* <xdc><<EOF>> gets its own rule so as to produce a more on-point
error message.
* Remove duplicate <SQL>{xdstart} rule.
John Naylor, with a few additional changes by me
Discussion: https://postgr.es/m/CAJVSVGWGqY9YBs2EwtRUkbNv=hXkN8yRPOoD1wxE6COgvvrz5g@mail.gmail.com
Commits c6b3c939b (which fixed the precedence of >=, <=, <> operators)
and 865f14a2d (which added support for the standard => notation for
named arguments) created a class of lexer tokens which look like
multi-character operators but which have their own token IDs distinct
from Op. However, longest-match rules meant that following any of
these tokens with another operator character, as in (1<>-1), would
cause them to be incorrectly returned as Op.
The error here isn't immediately obvious, because the parser would
usually still find the correct operator via the Op token, but there
were more subtle problems:
1. If immediately followed by a comment or +-, >= <= <> would be given
the old precedence of Op rather than the correct new precedence;
2. If followed by a comment, != would be returned as Op rather than as
NOT_EQUAL, causing it not to be found at all;
3. If followed by a comment or +-, the => token for named arguments
would be lexed as Op, causing the argument to be mis-parsed as a
simple expression, usually causing an error.
Fix by explicitly checking for the operators in the {operator} code
block in addition to all the existing special cases there.
Backpatch to 9.5 where the problem was introduced.
Analysis and patch by me; review by Tom Lane.
Discussion: https://postgr.es/m/87va851ppl.fsf@news-spur.riddles.org.uk
The lexer's handling of operators contained an O(N^3) hazard when
dealing with long strings of + or - characters; it seems hard to
prevent this case from being O(N^2), but the additional N multiplier
was not needed.
Backpatch all the way since this has been there since 7.x, and it
presents at least a mild hazard in that trying to do Bind, PREPARE or
EXPLAIN on a hostile query could take excessive time (without
honouring cancels or timeouts) even if the query was never executed.
Flex generates a lot of functions that are not actually used. In order
to avoid coverage figures being ruined by that, mark up the part of the
.l files where the generated code appears by lcov exclusion markers.
That way, lcov will typically only reported on coverage for the .l file,
which is under our control, but not for the .c file.
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
"\if :{?variable_name}" will be translated to "\if TRUE" if the variable
exists and "\if FALSE" otherwise. Thus it will be possible to execute code
conditionally on the existence of the variable, regardless of its value.
Fabien Coelho, with some review by Robins Tharakan and some light text
editing by me.
Discussion: https://postgr.es/m/alpine.DEB.2.20.1708260835520.3627@lancre
Previously, text between backquotes in a psql metacommand's arguments
was always passed to the shell literally. That considerably hobbles
the usefulness of the feature for scripting, so we'd foreseen for a long
time that we'd someday want to allow substitution of psql variables into
the shell command. IMO the addition of \if metacommands has brought us to
that point, since \if can greatly benefit from some sort of client-side
expression evaluation capability, and psql itself is not going to grow any
such thing in time for v10. Hence, this patch. It allows :VARIABLE to be
replaced by the exact contents of the named variable, while :'VARIABLE'
is replaced by the variable's contents suitably quoted to become a single
shell-command argument. (The quoting rules for that are different from
those for SQL literals, so this is a bit of an abuse of the :'VARIABLE'
notation, but I doubt anyone will be confused.)
As with other situations in psql, no substitution occurs if the word
following a colon is not a known variable name. That limits the risk of
compatibility problems for existing psql scripts; but the risk isn't zero,
so this needs to be called out in the v10 release notes.
Discussion: https://postgr.es/m/9561.1490895211@sss.pgh.pa.us
The immediate motivation for this is to provide clean infrastructure
for the proposed \if...\endif patch for psql; but it seems like a good
thing to have even if that patch doesn't get in. Previously the callback
functions could only make use of application-global state, which is a
pretty severe handicap.
For the moment, the pointer is only passed through to the get_variable
callback function. I considered also passing it to the write_error
callback, but for now let's not. Neither psql nor pgbench has a use
for that, and in the case of psql we'd have to invent a separate wrapper
function because we would certainly not want to change the signature of
psql_error().
Discussion: https://postgr.es/m/10108.1489418309@sss.pgh.pa.us
This completes (at least for now) the project of getting rid of ad-hoc
linkages among the src/bin/ subdirectories. Everything they share is now
in src/fe_utils/ and is included from a static library at link time.
A side benefit is that we can restore the FLEX_NO_BACKUP check for
psqlscanslash.l. We might need to think of another way to do that check
if we ever need to build two lexers with that property in the same source
directory, but there's no foreseeable reason to need that.
Tom Lane
Andrew Gierth
Bruce Momjian
Peter Eisentraut
Andrew Dunstan