Commit 8561e4840c neglected to handle
older Python versions that don't support the "with" statement. So write
the tests in a way that older versions can handle as well.
In each of the supplied procedural languages (PL/pgSQL, PL/Perl,
PL/Python, PL/Tcl), add language-specific commit and rollback
functions/commands to control transactions in procedures in that
language. Add similar underlying functions to SPI. Some additional
cleanup so that transaction commit or abort doesn't blow away data
structures still used by the procedure call. Add execution context
tracking to CALL and DO statements so that transaction control commands
can only be issued in top-level procedure and block calls, not function
calls or other procedure or block calls.
- SPI
Add a new function SPI_connect_ext() that is like SPI_connect() but
allows passing option flags. The only option flag right now is
SPI_OPT_NONATOMIC. A nonatomic SPI connection can execute transaction
control commands, otherwise it's not allowed. This is meant to be
passed down from CALL and DO statements which themselves know in which
context they are called. A nonatomic SPI connection uses different
memory management. A normal SPI connection allocates its memory in
TopTransactionContext. For nonatomic connections we use PortalContext
instead. As the comment in SPI_connect_ext() (previously SPI_connect())
indicates, one could potentially use PortalContext in all cases, but it
seems safest to leave the existing uses alone, because this stuff is
complicated enough already.
SPI also gets new functions SPI_start_transaction(), SPI_commit(), and
SPI_rollback(), which can be used by PLs to implement their transaction
control logic.
- portalmem.c
Some adjustments were made in the code that cleans up portals at
transaction abort. The portal code could already handle a command
*committing* a transaction and continuing (e.g., VACUUM), but it was not
quite prepared for a command *aborting* a transaction and continuing.
In AtAbort_Portals(), remove the code that marks an active portal as
failed. As the comment there already predicted, this doesn't work if
the running command wants to keep running after transaction abort. And
it's actually not necessary, because pquery.c is careful to run all
portal code in a PG_TRY block and explicitly runs MarkPortalFailed() if
there is an exception. So the code in AtAbort_Portals() is never used
anyway.
In AtAbort_Portals() and AtCleanup_Portals(), we need to be careful not
to clean up active portals too much. This mirrors similar code in
PreCommit_Portals().
- PL/Perl
Gets new functions spi_commit() and spi_rollback()
- PL/pgSQL
Gets new commands COMMIT and ROLLBACK.
Update the PL/SQL porting example in the documentation to reflect that
transactions are now possible in procedures.
- PL/Python
Gets new functions plpy.commit and plpy.rollback.
- PL/Tcl
Gets new commands commit and rollback.
Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
The previous code converted SPI_processed to a Python float if it didn't
fit into a Python int. But Python longs have unlimited precision, so
use that instead in all cases.
As in eee50a8d4c, we use the Python
LongLong API unconditionally for simplicity.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
We don't actually need two code paths, one for 32 bits and one for 64
bits. Since the existing code already assumed that "long long" is
available, we can just use PyLong_FromLongLong() for 64 bits as well.
In Python 2.5 and later, PyLong_FromLong() and PyLong_FromLongLong() use
the same code, so there will be no difference for 64-bit platforms. In
Python 2.4, the code is different, but performance testing showed no
noticeable difference in PL/Python, and that Python version is ancient
anyway.
Discussion: https://www.postgresql.org/message-id/0a02203c-e157-55b2-464e-6087066a1849@2ndquadrant.com
AclObjectKind was basically just another enumeration for object types,
and we already have a preferred one for that. It's only used in
aclcheck_error. By using ObjectType instead, we can also give some more
precise error messages, for example "index" instead of "relation".
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
PL/pgSQL "pins" internally generated portals so that user code cannot
close them by guessing their names. Add this functionality to PL/Perl
and PL/Python as well, preventing users from manually closing cursors
created by spi_query and plpy.cursor, respectively. (PL/Tcl does not
currently offer any cursor functionality.)
PL/pgSQL "pins" internally generated (unnamed) portals so that user code
cannot close them by guessing their names. This logic is also useful in
other languages and really for any code. So move that logic into SPI.
An unnamed portal obtained through SPI_cursor_open() and related
functions is now automatically pinned, and SPI_cursor_close()
automatically unpins a portal that is pinned.
In the core distribution, this affects PL/Perl and PL/Python, preventing
users from manually closing cursors created by spi_query and
plpy.cursor, respectively. (PL/Tcl does not currently offer any cursor
functionality.)
Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
plpgsql's five different loop control statements contained three distinct
implementations of the same (or what ought to be the same, at least)
logic for handling return/exit/continue result codes from their child
statements. At best, that's trouble waiting to happen, and there seems
no very good reason for the coding to be so different. Refactor so that
all the common logic is expressed in a single macro.
Discussion: https://postgr.es/m/26314.1514670401@sss.pgh.pa.us
I noticed that our code coverage report showed considerable deficiency
in test coverage for PL/pgSQL control statements. Notably, both
exec_stmt_block and most of the loop control statements had very poor
coverage of handling of return/exit/continue result codes from their
child statements; and exec_stmt_fori was seriously lacking in feature
coverage, having no test that exercised its BY or REVERSE features,
nor verification that its overflow defenses work.
Now that we have some infrastructure for plpgsql-specific test scripts,
the natural thing to do is make a new script rather than further extend
plpgsql.sql. So I created a new script plpgsql_control.sql with the
charter to test plpgsql control structures, and moved a few existing
tests there because they fell entirely under that charter. I then
added new test cases that exercise the bits of code complained of above.
Of the five kinds of loop statements, only exec_stmt_while's result code
handling is fully exercised by these tests. That would be a deficiency
as things stand, but a follow-on commit will merge the loop statements'
result code handling into one implementation. So testing each usage of
that implementation separately seems redundant.
In passing, also add a couple test cases to plpgsql.sql to more fully
exercise plpgsql's code related to expanded arrays --- I had thought
that area was sufficiently covered already, but the coverage report
showed a couple of un-executed code paths.
Discussion: https://postgr.es/m/26314.1514670401@sss.pgh.pa.us
This patch does three interrelated things:
* Create a new expression execution step type EEOP_PARAM_CALLBACK
and add the infrastructure needed for add-on modules to generate that.
As discussed, the best control mechanism for that seems to be to add
another hook function to ParamListInfo, which will be called by
ExecInitExpr if it's supplied and a PARAM_EXTERN Param is found.
For stand-alone expressions, we add a new entry point to allow the
ParamListInfo to be specified directly, since it can't be retrieved
from the parent plan node's EState.
* Redesign the API for the ParamListInfo paramFetch hook so that the
ParamExternData array can be entirely virtual. This also lets us get rid
of ParamListInfo.paramMask, instead leaving it to the paramFetch hook to
decide which param IDs should be accessible or not. plpgsql_param_fetch
was already doing the identical masking check, so having callers do it too
seemed redundant. While I was at it, I added a "speculative" flag to
paramFetch that the planner can specify as TRUE to avoid unwanted failures.
This solves an ancient problem for plpgsql that it couldn't provide values
of non-DTYPE_VAR variables to the planner for fear of triggering premature
"record not assigned yet" or "field not found" errors during planning.
* Rework plpgsql to get rid of the need for "unshared" parameter lists,
by dint of turning the single ParamListInfo per estate into a nearly
read-only data structure that doesn't instantiate any per-variable data.
Instead, the paramFetch hook controls access to per-variable data and can
make the right decisions on the fly, replacing the cases that we used to
need multiple ParamListInfos for. This might perhaps have been a
performance loss on its own, but by using a paramCompile hook we can
bypass plpgsql_param_fetch entirely during normal query execution.
(It's now only called when, eg, we copy the ParamListInfo into a cursor
portal. copyParamList() or SerializeParamList() effectively instantiate
the virtual parameter array as a simple physical array without a
paramFetch hook, which is what we want in those cases.) This allows
reverting most of commit 6c82d8d1f, though I kept the cosmetic
code-consolidation aspects of that (eg the assign_simple_var function).
Performance testing shows this to be at worst a break-even change,
and it can provide wins ranging up to 20% in test cases involving
accesses to fields of "record" variables. The fact that values of
such variables can now be exposed to the planner might produce wins
in some situations, too, but I've not pursued that angle.
In passing, remove the "parent" pointer from the arguments to
ExecInitExprRec and related functions, instead storing that pointer in a
transient field in ExprState. The ParamListInfo pointer for a stand-alone
expression is handled the same way; we'd otherwise have had to add
yet another recursively-passed-down argument in expression compilation.
Discussion: https://postgr.es/m/32589.1513706441@sss.pgh.pa.us
Various Perl scripts we use to generate files were in the habit of
printing things like "generated by $0" into their output files.
That looks like a fine idea at first glance, but it results in
non-reproducible output, because in VPATH builds $0 won't be just
the name of the script file, but a full path for it. We'd prefer
that you get identical results whether using VPATH or not, so this
is a bad thing.
Some of these places also printed their input file name(s), causing
an additional hazard of the same type.
Hence, establish a policy that thou shalt not print $0, nor input file
pathnames, into output files (they're still allowed in error messages,
though). Instead just write the script name verbatim. While we are at
it, we can make these annotations more useful by giving the script's
full relative path name within the PG source tree, eg instead of
Gen_fmgrtab.pl let's print src/backend/utils/Gen_fmgrtab.pl.
Not all of the changes made here actually affect any files shipped
in finished tarballs today, but it seems best to apply the policy
everyplace so that nobody copies unsafe code into places where it
could matter.
Christoph Berg and Tom Lane
Discussion: https://postgr.es/m/20171215102223.GB31812@msg.df7cb.de
Fix a couple of minor oversights in commit 632b03da3: the tests
should be run in database "pl_regression" like the other PLs do,
and we should clean up the tests' output cruft during "make clean".
This patch makes a number of interrelated changes to reduce the overhead
involved in creating/deleting memory contexts. The key ideas are:
* Include the AllocSetContext header of an aset.c context in its first
malloc request, rather than allocating it separately in TopMemoryContext.
This means that we now always create an initial or "keeper" block in an
aset, even if it never receives any allocation requests.
* Create freelists in which we can save and recycle recently-destroyed
asets (this idea is due to Robert Haas).
* In the common case where the name of a context is a constant string,
just store a pointer to it in the context header, rather than copying
the string.
The first change eliminates a palloc/pfree cycle per context, and
also avoids bloat in TopMemoryContext, at the price that creating
a context now involves a malloc/free cycle even if the context never
receives any allocations. That would be a loser for some common
usage patterns, but recycling short-lived contexts via the freelist
eliminates that pain.
Avoiding copying constant strings not only saves strlen() and strcpy()
overhead, but is an essential part of the freelist optimization because
it makes the context header size constant. Currently we make no
attempt to use the freelist for contexts with non-constant names.
(Perhaps someday we'll need to think harder about that, but in current
usage, most contexts with custom names are long-lived anyway.)
The freelist management in this initial commit is pretty simplistic,
and we might want to refine it later --- but in common workloads that
will never matter because the freelists will never get full anyway.
To create a context with a non-constant name, one is now required to
call AllocSetContextCreateExtended and specify the MEMCONTEXT_COPY_NAME
option. AllocSetContextCreate becomes a wrapper macro, and it includes
a test that will complain about non-string-literal context name
parameters on gcc and similar compilers.
An unfortunate side effect of making AllocSetContextCreate a macro is
that one is now *required* to use the size parameter abstraction macros
(ALLOCSET_DEFAULT_SIZES and friends) with it; the pre-9.6 habit of
writing out individual size parameters no longer works unless you
switch to AllocSetContextCreateExtended.
Internally to the memory-context-related modules, the context creation
APIs are simplified, removing the rather baroque original design whereby
a context-type module called mcxt.c which then called back into the
context-type module. That saved a bit of code duplication, but not much,
and it prevented context-type modules from exercising control over the
allocation of context headers.
In passing, I converted the test-and-elog validation of aset size
parameters into Asserts to save a few more cycles. The original thought
was that callers might compute size parameters on the fly, but in practice
nobody does that, so it's useless to expend cycles on checking those
numbers in production builds.
Also, mark the memory context method-pointer structs "const",
just for cleanliness.
Discussion: https://postgr.es/m/2264.1512870796@sss.pgh.pa.us
The plpgsql.sql test file in the main regression tests is now by far the
largest after numeric_big, making editing and managing the test cases
very cumbersome. The other PLs have their own test suites split up into
smaller files by topic. It would be nice to have that for plpgsql as
well. So, to get that started, set up test infrastructure in
src/pl/plpgsql/src/ and split out the recently added procedure test
cases into a new file there. That file now mirrors the test cases added
to the other PLs, making managing those matching tests a bit easier too.
msvc build system changes with help from Michael Paquier
After d0aa965c0a, one error path in
PLy_spi_execute_fetch_result() could result in the variable "result"
being dereferenced after being set to NULL. Rearrange the code a bit to
fix that.
Also add another SPI_freetuptable() call so that that is cleared in all
error paths.
discovered by John Naylor <jcnaylor@gmail.com> via scan-build
ideas and review by Tom Lane
If one exits and re-enters a DECLARE ... BEGIN ... END block within a
single execution of a plpgsql function, perhaps due to a surrounding loop,
the declared variables are supposed to get re-initialized to null (or
whatever their initializer is). But this failed to happen for variables
of type "record", because while exec_stmt_block() expected such variables
to be included in the block's initvarnos list, plpgsql_add_initdatums()
only adds DTYPE_VAR variables to that list. This bug appears to have
been there since the aboriginal addition of plpgsql to our tree.
Fix by teaching plpgsql_add_initdatums() to include DTYPE_REC variables
as well. (We don't need to consider other DTYPEs because they don't
represent separately-stored values.) I failed to resist the temptation
to make some nearby cosmetic adjustments, too.
No back-patch, because there have not been field complaints, and it
seems possible that somewhere out there someone has code depending
on the incorrect behavior. In any case this change would have no
impact on correctly-written code.
Discussion: https://postgr.es/m/22994.1512800671@sss.pgh.pa.us
plpgsql's function exec_move_row() handles assignment of a composite
source value to either a PLpgSQL_rec or PLpgSQL_row target variable.
Oddly, rather than taking a single target argument which it could do
run-time type detection on, it was coded to take two separate arguments
(only one of which is allowed to be non-NULL). This choice had then
back-propagated into storing two separate target variables in various
plpgsql statement nodes, with lots of duplicative coding and awkward
interface logic to support that. Simplify matters by folding those
pairs down to single variables, distinguishing the two cases only
where we must ... which turns out to be only in exec_move_row itself.
This is purely refactoring and should not change any behavior.
In passing, remove unused field PLpgSQL_stmt_open.returntype.
Discussion: https://postgr.es/m/11787.1512713374@sss.pgh.pa.us
I'm a little bit astonished that anyone's compiler would have failed to
complain about this. The compiler surely does not know that is_procedure
means the function return value will be ignored.
This adds a new object type "procedure" that is similar to a function
but does not have a return type and is invoked by the new CALL statement
instead of SELECT or similar. This implementation is aligned with the
SQL standard and compatible with or similar to other SQL implementations.
This commit adds new commands CALL, CREATE/ALTER/DROP PROCEDURE, as well
as ALTER/DROP ROUTINE that can refer to either a function or a
procedure (or an aggregate function, as an extension to SQL). There is
also support for procedures in various utility commands such as COMMENT
and GRANT, as well as support in pg_dump and psql. Support for defining
procedures is available in all the languages supplied by the core
distribution.
While this commit is mainly syntax sugar around existing functionality,
future features will rely on having procedures as a separate object
type.
Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
Apparently, scan-build thinks that proc->is_setof can change during
PLy_exec_function(). To make it clearer, save the value in a local
variable.
Also add an assertion to clear another warning.
Reviewed-by: John Naylor <jcnaylor@gmail.com>
Decorate PLy_elog() in a similar way as elog(), to give compilers and
static analyzers hints in which cases it does not return.
Reviewed-by: John Naylor <jcnaylor@gmail.com>
After d0aa965c0a, one error path in
PLy_spi_execute_fetch_result() could result in the variable "result"
being dereferenced after being set to NULL. To fix that, just clear the
resources right there and return early.
Also add another SPI_freetuptable() call so that that is cleared in all
error paths.
discovered by John Naylor <jcnaylor@gmail.com> via scan-build
This is necessary for ActivePerl 5.18 onwards and for Strawberry Perl.
It is not sufficient for 32-bit builds with newer Visual Studio; these
fail with error LINK2026. Back-patch to 9.3 (all supported versions).
Reported by Victor Wagner.
Discussion: https://postgr.es/m/20160326154321.7754ab8f@wagner.wagner.home
Python Py*_New() functions can fail and return NULL in out-of-memory
conditions. The previous code handled that inconsistently or not at
all. This change organizes that better. If we are in a function that
is called from Python, we just check for failure and return NULL
ourselves, which will cause any exception information to be passed up.
If we are called from PostgreSQL, we consistently create an "out of
memory" error.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Fix PL/Python so that it can handle domains over composite, and so that
it enforces domain constraints correctly in other cases that were not
always done properly before. Notably, it didn't do arrays of domains
right (oversight in commit c12d570fa), and it failed to enforce domain
constraints when returning a composite type containing a domain field,
and if a transform function is being used for a domain's base type then
it failed to enforce domain constraints on the result. Also, in many
places it missed checking domain constraints on null values, because
the plpy_typeio code simply wasn't called for Py_None.
Rather than try to band-aid these problems, I made a significant
refactoring of the plpy_typeio logic. The existing design of recursing
for array and composite members is extended to also treat domains as
containers requiring recursion, and the APIs for the module are cleaned
up and simplified.
The patch also modifies plpy_typeio to rely on the typcache more than
it did before (which was pretty much not at all). This reduces the
need for repetitive lookups, and lets us get rid of an ad-hoc scheme
for detecting changes in composite types. I added a couple of small
features to typcache to help with that.
Although some of this is fixing bugs that long predate v11, I don't
think we should risk a back-patch: it's a significant amount of code
churn, and there've been no complaints from the field about the bugs.
Tom Lane, reviewed by Anthony Bykov
Discussion: https://postgr.es/m/24449.1509393613@sss.pgh.pa.us
The lower case spellings are C and C++ standard and are used in most
parts of the PostgreSQL sources. The upper case spellings are only used
in some files/modules. So standardize on the standard spellings.
The APIs for ICU, Perl, and Windows define their own TRUE and FALSE, so
those are left as is when using those APIs.
In code comments, we use the lower-case spelling for the C concepts and
keep the upper-case spelling for the SQL concepts.
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
In passing, don't insist on rsi->expectedDesc being set unless we
actually need it; this allows succeeding in a couple of cases where
PL/Perl functions returning setof composite would have failed before,
and makes the error message more apropos in other cases.
Discussion: https://postgr.es/m/4206.1499798337@sss.pgh.pa.us
This was always intended to work, but due to an oversight in
max_parallel_hazard_walker, it didn't. In testing, we missed the
fact that it was only working for custom plans, where the parameter
value has been substituted for the parameter itself early enough
that everything worked. In a generic plan, the Param node survives
and must be treated as parallel-safe. SerializeParamList provides
for the transmission of parameter values to workers.
Amit Kapila with help from Kuntal Ghosh. Some changes by me.
Discussion: http://postgr.es/m/CAA4eK1+_BuZrmVCeua5Eqnm4Co9DAXdM5HPAOE2J19ePbR912Q@mail.gmail.com
Since PL/Tcl does little with SQL types internally, this is just a
matter of making it work with composite-domain function arguments
and results.
In passing, make it allow RECORD-type arguments --- that's a trivial
change that nobody had bothered with up to now.
Discussion: https://postgr.es/m/4206.1499798337@sss.pgh.pa.us
The changes in 639928c988 turned out to
require Perl 5.9.3, which is newer than our minimum required version.
So revert back to the old code for the normal case and only use the new
variant when both coverage and vpath are used. As the minimum Perl
version moves forward, we can drop the old code sometime.
Run xsubpp with the -output option instead of redirecting stdout. That
ensures that the #line directives in the output file point to the right
place in a vpath build. This in turn fixes an error in coverage builds
that it can't find the source files.
Refactor the makefile rules while we're here.
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
This is a mechanical change in preparation for a later commit that
will change the layout of TupleDesc. Introducing a macro to abstract
the details of where attributes are stored will allow us to change
that in separate step and revise it in future.
Author: Thomas Munro, editorialized by Andres Freund
Reviewed-By: Andres Freund
Discussion: https://postgr.es/m/CAEepm=0ZtQ-SpsgCyzzYpsXS6e=kZWqk3g5Ygn3MDV7A8dabUA@mail.gmail.com
Commit 00418c612 expected that the plan generated for a simple-expression
query would always be a plain Result node. However, if force_parallel_mode
is on, the planner might stick a Gather atop that. Cope by looking through
the Gather. For safety, assert that the Gather's tlist is trivial.
Per buildfarm.
Discussion: https://postgr.es/m/23425.1502822098@sss.pgh.pa.us
plpgsql wants to recognize expressions that it can execute directly
via ExecEvalExpr() instead of going through the full SPI machinery.
Originally the test for this consisted of recursively groveling through
the post-planning expression tree to see if it contained only nodes that
plpgsql recognized as safe. That was a major maintenance headache, since
it required updating plpgsql every time we added any kind of expression
node. It was also kind of expensive, so over time we added various
pre-planning checks to try to short-circuit having to do that.
Robert Haas pointed out that as of the SRF-processing changes in v10,
particularly the addition of Query.hasTargetSRFs, there really isn't
any reason to make the recursive scan at all: the initial checks cover
everything we really care about. We do have to make sure that those
checks agree with what inline_function() considers, so that inlining
of a function that formerly wasn't inlined can't cause an expression
considered simple to become non-simple.
Hence, delete the recursive function exec_simple_check_node(), and tweak
those other tests to more exactly agree with inline_function(). Adjust
some comments and function naming to match.
Discussion: https://postgr.es/m/CA+TgmoZGZpwdEV2FQWaVxA_qZXsQE1DAS5Fu8fwxXDNvfndiUQ@mail.gmail.com
Coverity complained about this code's practice of using scalar variables
as single-element arrays. While that's really just nitpicking, it probably
is more readable to declare them as arrays, so let's do that. A more
important point is that the code was just blithely assuming that the
result tupledesc has exactly one column; if it doesn't, we'd likely get
a crash of some sort in tuplestore_putvalues. Since the tupledesc is
manufactured outside of plperl, that seems like an uncomfortably long
chain of assumptions. We can nail it down at little cost with a sanity
check earlier in the function.
The Perl documentation is very clear that stuff calling libperl should
be built with the compiler switches shown by Perl's $Config{ccflags}.
We'd been ignoring that up to now, and mostly getting away with it,
but recent Perl versions contain ABI compatibility cross-checks that
fail on some builds because of this omission. In particular the
sizeof(PerlInterpreter) can come out different due to some fields being
added or removed; which means we have a live ABI hazard that we'd better
fix rather than continuing to sweep it under the rug.
However, it still seems like a bad idea to just absorb $Config{ccflags}
verbatim. In some environments Perl was built with a different compiler
that doesn't even use the same switch syntax. -D switch syntax is pretty
universal though, and absorbing Perl's -D switches really ought to be
enough to fix the problem.
Furthermore, Perl likes to inject stuff like -D_LARGEFILE_SOURCE and
-D_FILE_OFFSET_BITS=64 into $Config{ccflags}, which affect libc ABIs on
platforms where they're relevant. Adopting those seems dangerous too.
It's unclear whether a build wherein Perl and Postgres have different ideas
of sizeof(off_t) etc would work, or whether anyone would care about making
it work. But it's dead certain that having different stdio ABIs in
core Postgres and PL/Perl will not work; we've seen that movie before.
Therefore, let's also ignore -D switches for symbols beginning with
underscore. The symbols that we actually need to import should be the ones
mentioned in perl.h's PL_bincompat_options stanza, and none of those start
with underscore, so this seems likely to work. (If it turns out not to
work everywhere, we could consider intersecting the symbols mentioned in
PL_bincompat_options with the -D switches. But that will be much more
complicated, so let's try this way first.)
This will need to be back-patched, but first let's see what the
buildfarm makes of it.
Ashutosh Sharma, some adjustments by me
Discussion: https://postgr.es/m/CANFyU97OVQ3+Mzfmt3MhuUm5NwPU=-FtbNH5Eb7nZL9ua8=rcA@mail.gmail.com
In Perl builds that define PERL_IMPLICIT_SYS, XSUB.h defines macros
that replace a whole lot of basic libc functions with Perl functions.
We can't tolerate that in plperl.c; it breaks at least PG_TRY and
probably other stuff. The core idea of this patch is to include XSUB.h
only in the .xs files where it's really needed, and to move any code
broken by PERL_IMPLICIT_SYS out of the .xs files and into plperl.c.
The reason this hasn't been a problem before is that our build techniques
did not result in PERL_IMPLICIT_SYS appearing as a #define in PL/Perl,
even on some platforms where Perl thinks it is defined. That's about to
change in order to fix a nasty portability issue, so we need this work to
make the code safe for that.
Rather unaccountably, the Perl people chose XSUB.h as the place to provide
the versions of the aTHX/aTHX_ macros that are needed by code that's not
explicitly aware of the MULTIPLICITY API conventions. Hence, just removing
XSUB.h from plperl.c fails miserably. But we can work around that by
defining PERL_NO_GET_CONTEXT (which would make the relevant stanza of
XSUB.h a no-op anyway). As explained in perlguts.pod, that means we need
to add a "dTHX" macro call in every C function that calls a Perl API
function. In most of them we just add this at the top; but since the
macro fetches the current Perl interpreter pointer, more care is needed
in functions that switch the active interpreter. Lack of the macro is
easily recognized since it results in bleats about "my_perl" not being
defined.
(A nice side benefit of this is that it significantly reduces the number
of fetches of the current interpreter pointer. On my machine, plperl.so
gets more than 10% smaller, and there's probably some performance win too.
We could reduce the number of fetches still more by decorating the code
with pTHX_/aTHX_ macros to pass the interpreter pointer around, as
explained by perlguts.pod; but that's a task for another day.)
Formatting note: pgindent seems happy to treat "dTHX;" as a declaration
so long as it's the first thing after the left brace, as we'd already
observed with respect to the similar macro "dSP;". If you try to put
it later in a set of declarations, pgindent puts ugly extra space
around it.
Having removed XSUB.h from plperl.c, we need only move the support
functions for spi_return_next and util_elog (both of which use PG_TRY)
out of the .xs files and into plperl.c. This seems sufficient to
avoid the known problems caused by PERL_IMPLICIT_SYS, although we
could move more code if additional issues emerge.
This will need to be back-patched, but first let's see what the
buildfarm makes of it.
Patch by me, with some help from Ashutosh Sharma
Discussion: https://postgr.es/m/CANFyU97OVQ3+Mzfmt3MhuUm5NwPU=-FtbNH5Eb7nZL9ua8=rcA@mail.gmail.com
('foo') is not a Python tuple: it is a string wrapped in parentheses. A
valid 1-element Python tuple is ('foo',).
Author: Daniele Varrazzo <daniele.varrazzo@gmail.com>
Don't move parenthesized lines to the left, even if that means they
flow past the right margin.
By default, BSD indent lines up statement continuation lines that are
within parentheses so that they start just to the right of the preceding
left parenthesis. However, traditionally, if that resulted in the
continuation line extending to the right of the desired right margin,
then indent would push it left just far enough to not overrun the margin,
if it could do so without making the continuation line start to the left of
the current statement indent. That makes for a weird mix of indentations
unless one has been completely rigid about never violating the 80-column
limit.
This behavior has been pretty universally panned by Postgres developers.
Hence, disable it with indent's new -lpl switch, so that parenthesized
lines are always lined up with the preceding left paren.
This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
Change pg_bsd_indent to follow upstream rules for placement of comments
to the right of code, and remove pgindent hack that caused comments
following #endif to not obey the general rule.
Commit e3860ffa4d wasn't actually using
the published version of pg_bsd_indent, but a hacked-up version that
tried to minimize the amount of movement of comments to the right of
code. The situation of interest is where such a comment has to be
moved to the right of its default placement at column 33 because there's
code there. BSD indent has always moved right in units of tab stops
in such cases --- but in the previous incarnation, indent was working
in 8-space tab stops, while now it knows we use 4-space tabs. So the
net result is that in about half the cases, such comments are placed
one tab stop left of before. This is better all around: it leaves
more room on the line for comment text, and it means that in such
cases the comment uniformly starts at the next 4-space tab stop after
the code, rather than sometimes one and sometimes two tabs after.
Also, ensure that comments following #endif are indented the same
as comments following other preprocessor commands such as #else.
That inconsistency turns out to have been self-inflicted damage
from a poorly-thought-through post-indent "fixup" in pgindent.
This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
