Ann: SWI-Prolog 8.4.3 (stable)

jan · June 22, 2022, 10:03am

Dear SWI-Prolog user,

There is finally an update for the SWI-Prolog stable series: 8.4.3. Many
things happened in the development branch, including patches that
introduced many changes and (thus) complicate backporting. Roughly,
the 8.4.3 release picks most patches from the development version that
have no or very low compatibility impact. Some big changes are notably

EXCLUDED:

All the work on allowing to shutdown and re-create Prolog in the
same process (PL_cleanup()). Besides allowing to restart, this
work improved memory management a lot. It is considered too
involved to include in the stable version.
Most of the work by @dmchurch preparing for a better WASM version,
notably on signal handling.
Conditional breakpoints by @oskardrums (because it involves an
interface change).
Low level coverage data collection
This version also stays at pcre version 1.

Still, there are some highlights

Many updates, notably to the tools, for det/1, => rules, $/0
and $/1.
Fixes to dif/2
Fixed many Windows portability issues
Fixed several memory leaks (still, use the development version
is this is critical to you).
Improved UDP socket support.
PPA now have debug symbols.

Although all tests pass, regression as a result of backporting many
patches is not unlikely. Please test and report so they can be fixed
and we can release 8.4.4.

Two patches have already been applied to git and the Ubuntu jammy
PPA:

Revert the last patch on show_coverage/1,2 that relies on the new
data collection. This implies show_coverage/1,2 is broken on all
versions except for the jammy PPA.
Include the latest patches for the SSL package. Some portability
patches were omitted, one breaking the tests in the package build
environment on Ubuntu jammy.

Enjoy — Jan

SWI-Prolog Changelog since version 8.4.2

FIXED: Issue#114: Windows getenv/2 may return additional garbage
(typically an extra \u0000 character at the end of variables of
1023 bytes or longer because the 0-byte is not added. Paul Singleton.
FIXED: Several issues to consistently deal with buffer sizes in
os/windows/uxnt.c.
FIXED: Sfprintf(): handling of ENC_WCHAR() encoding.
ENHANCED: Sfprintf(): allow Unicode characters for %c
ENHANCED: PL_record_external() deal with records > 2Gb on 64 bit
platforms.
FIXED: write_term/2 and friends handling of embrace of operants that
are operators for partial writes.
FIXED: no space is required between a space and (.
FIXED: write_term/2 and friends: do not embrace writing a single atom
if this is an operator and the priority(Priority) option is given.
DOC: Create links for S*() function references
DOC: Started documenting SWI-Stream.h
FIXED: Sgets() handling of non-0-terminated output from Sfgets().
DOC: ord_intersection/2 is semidet.
DIST: Fixed rmd160 generation for scripts/update-macports
FIXED: write_term/2 with numbervars and variable_names (#866)
FIXED: Issue#993: possible deadlock when loading a module. Reported by
Sean Leather.
FIXED: eliminated a spurious choice-point in sub_atom/5 Reported in
Careful with sub_atom/5 and feature request last_sub_atom/5
DOC: enhance documentation for det/, $/1 and $/0, describing the
exceptions and how trap/1 can be used to make the debugger act quickly.
FIXED: explain/1: hide references from prolog_xref:called/5
FIXED: Have breakpoints cleared in the UI when the clause that holds
them is removed during a reload of the file.
FIXED: breakpoint_property/2: fixed character_range property
ENHANCED: Issue#17: reverse/2 to be deterministic if second argument
is a proper list. Ulrich Neumerkel.
TEST: Added STO restriction as this test involves rational trees.
FIXED: Issue#122: dif/2: or-node simplification.
FIXED: Possible deadlock enumerating predicates from a source file.
FIXED: Avoid Unicode quote in library(aggregate) comment
FIXED: LaTeX conflict preventing building the PDF docs
FIXED: Possible race condition importing into a module. Can lead to
termination on a system error.
FIXED: Make source layout handling aware that debug/3 and assertion/1
may be removed by the optimizer.
ADDED: Sopen_iri_or_file() API to allow foreign code to access the
resources.
ENHANCED: require/1 to simply import if the target module is already
loaded. Reduces startup time.
FIXED: fd_degree/2 and fd_set/2 for constant integer arguments.
DOC: added cross-references from absolute_file_name/3 to
file_search_path/2.
ADDED: library(sandbox): allow declaring prolog flags as safe.
ADDED: open/4 option newline(Mode).
DOC: Updated clause/2.
FIXED: Memory leak reading Unicode queries at the toplevel.
Peter Ludemann.
ADDED: library(sandbox): support predicate_property/2
DOC: PL_atom_wchars(): wrong types
ADDED: library(sandbox): functor/4.
FIXED: Possible wrong Windows drive letter normalisation.
PORT: msys2, detect libdb-6.0.dll from libdb.a
PORT: Msys2/clang64
PORT: MSYS2/clang64 the dll name appears several times in the “.a”
file, select the first appearance
FIXED: swipl-ld didn’t pass -I for SWI-Prolog.h any more.
PORT: Sopenmem() to use SIO_NL_POSIX. All internal strings use
POSIX \n to delimit lines. @mgodan1.
FIXED: copy_term/4 to handle cyclic terms for the first argument.
Also proper recovery in case of a memory overflow.
DOC: open/3,4 pipe(Command) limitations.
PORT: open/3,4 on Windows: use clib popen() instead of the broken
emulation in src/os/windows/popen.c
FIXED: Clause position management for h => X = ..., rest_body:
the unification is not inlined.
FIXED: swipl-ld: access to uninitialized memory
FIXED: current_predicate/1 bug in updating module reference count
that may cause temporary modules not to be destroyed. Notably affects
SWISH.
DOC: Add transpose/2 to the clpfd docs.
FIXED: bulk mode for transactions was not actually passed.
FIXED: retract in nested transaction of a clause asserted in the
outer transaction to properly reclaim the clause.
FIXED: fast_term_serialized/2: memory leak.
FIXED: Avoid transaction rollback to be recorded (memory leak).
FIXED: Avoid leaking a trie node on concurrent insert of the same
value.
ENHANCED: if we created a supervisor that is equal to the existing,
discard the new one. This may happen if multiple threads create
a supervisor. Leaks memory as we cannot safely discard a running
supervisor.
FIXED: consistent use of tree pool allocation.
FIXED: Initial atom table was allocated twice. Also set the initial
size for this table to be big enough to load the initial state,
avoiding two rehash operations.
FIXED: Reclaim argument admin for destroyed predicates.
FIXED: Typo on threadutil.pl, harming operation without xpce.
Johan Romme.
ADDED: Make encoding accessible by name using PL_atom_to_encoding()
and PL_encoding_to_atom()
DOC: tabling po(Compare) argument.
DOC: refer to pack debug_adapter in the GNU Emacs Interface page
FIXED: dif/2 not firing after unifying with other attributed variables.
FIXED: call_residue_vars/2: possible spurious reported variables
because the trail entry was removed but the variable was not reclaimed
due to a frozen stack.
ADDED: on_signal/3 now takes value ‘ignore’ This allows for requesting
the SIG_IGN disposition, and also unifies the SIGPIPE behavior with
the other initially-prepared signals. Technically, this could be
considered a backwards-incompatible change. However, for this to
actually affect someone’s working code, they would have to
1. Redefine the system predicate ignore/1,
2. Call on_signal(Sig, _, ignore), AND
3. Expect ignore(Signal) to do something besides ignoring Signal;
and in that case I think we can all agree they’ve brought this trouble
upon themselves.

Also adds SIGPIPE’s default disposition to the docs.
MODIFIED: fixing SIG_PROLOG_OFFSET at 32, per docs This also introduces
a set of macros to interact with the pending signal mask which should
hopefully ease refactoring if and when we change which signals swipl
supports, like adding support for system signals over 31.
MODIFIED: switching core libswipl code to C11 This allows for a
standards-compatible implementation of the LD macros that is guaranteed
to compile down to a simple reference even at -O0. I’ve also added
some code that, at least in my testing, makes print LD work again
in GDB and any debugger that uses it as a backend.
PORT: adding O_SIGNALS define in config.h This provides a single define
to check if Prolog’s signal-handling is enabled, rather than checking
each of HAVE_SIGNAL etc. This also makes the existence and use of
GD->signals.sig_alert consistent on whether SIG_ALERT is defined.
PORT: Do not depend on SIGINT if signal support is disabled.
PORT: Get optional symbols via weak linking This unifies the tcmalloc
and ptmalloc linking code and also allows systems without dlsym(),
like WASM, to expose the malloc-implementation predicates, so long
as the linker is capable of resolving weak symbols.
PORT: Issue#939: TLD_alloc() undefined error on Win32. @mgodan.
FIXED: Gui tracer for inlined unification with SSU clauses, e.g.
p(X), X = aap(N) => writeln(N).
FIXED: Allow tracing test predicates that are inlined into the VM.
FIXED: Make gui tracer handle inlined head unifications.
FIXED: rule/3 for => rules that have the unification moved into the
head and listing/1 for such SSU clauses.
FIXED: Preproc/build errors Adding a couple GCC builtins to the config
tests, using them to force short-circuiting of _LD_WITH_FALLBACK even
in low-optimization modes (e.g. Clang in DEBUG configuration).

Also adding a few missing-but-used defines to config.h.cmake
(HAVE___BUILTIN_EXPECT, HAVE___THREAD, HAVE_VOLATILE, and HAVE_INLINE)
and fixing an unbalanced #ifdef pair that got added in f3b79d6.
FIXED: Consider /0 a breakable instruction. This fixes the debugger for clauses holding /0.
FIXED: Avoid instantiation error on =…/2 when analysing clause
positions with incomplete information.
SANDBOX: SWISH issue#147: Allow for copy_term/4.
FIXED: Allow retry from the body of => rules.
ENHANCED: Avoid tracing inside spy/1, nospy/1 and related debug
control predicates.
FIXED: Issue#935: package manager: download location of git archives
DOC: Remove obsolete reference of break/1 trace port
FIXED: Issue#963: possible undefined to_list/2 in message
handling. Caused by wrong backport.

Package clib

FIXED: process_create/3: allow env([]).
FIXED: process_create/3: Windows: make environment(List) inherit the
environment as documented.
FIXED: process_create/3: double env/environment option raised an
assertion failure. Now raises a permission error.
TEST: Disable CGI test for Windows because environment variables set
using Prolog setenv/2 are not visible in the CRT runtime function
getenv(). This either requires updating the CGI module to use the
Win32 environment API or start a new process for reading the CGI input.
TEST: Cross-platform null in stream_input
ENHANCED: Close sockets that are reclaimed because their blob is
being garbage collected.
TEST: Basic tests for udp_send/4 and udp_receive/4.
ADDED: udp_send/4: as(Type) option.
ADDED: udp_receive/4 as(term) to parse the message into a Prolog
term.
ADDED: udp_receive/4 and udb_send/4: encoding(Enc) option to affect
the encoding.
CLEANUP: Use new PL_atom_to_encoding() to avoid code duplication.
TEST: Disable test killing non-existing process on MacOS. Can deliver
SIGTERM to Prolog itself when executed concurrently.
TEST: test_af_unix works without signals
FIXED: memory_file_to_atom/3: do not trap an assertion if the encoding
is not supported but raise a domain error instead.
FIXED: tcp_connect/3 and other predicates that rely on
nbio_get_sockaddr() to initialize the unused part of the address.

Package clpqr

FIXED: Missed module rename for attribute_goals//1. Reported by
Paul Bredbury.
MODIFIED: renamed internal modules with names that may easily conflict
to clpqr_ followed by the old name. As as result the attributes
on variables have also be renamed. Should not affect code unless
applications use explicitly qualified calls or directly manipulate
the attributes.
ENHANCED: Faster dump/3 implementation.

Package cpp

ADDED: PlFunctor class conversion and comparison to functor_t
TEST: Add Unicode/wchar tests
TEST: PL_atom_wchars print
TEST: Added foreign language interface regression tests

Package http

ADDED: Hook html_write:html_header_hook/1 to emit additional HTTP
headers for HTML pages.
ADDED: http_open/3: option raw_encoding(+Encoding) to prevent deconding
certain (transfer) encodings.
ADDED: http_open/3: option raw_headers(-Strings) to get access to
the unparsed HTTP header as a list of strings.
ADDED: http_post_data/3: support string(String) and string(Type,
String) simlar to atom(String) and atom(Type, String). Avoids creating
a potentially large garbage atom.
ENHANCED: Reduce overhead of session GC
PORT: Make CGI tests succeed on Windows. @mgodan1
UPDATED: Bundled jquery from jquery-1.11.3 to 3.6.0.
REVERT: It is not a good idea to handle file input not as binary.
FIXED: HTTP multipart message handling: set encoding for uploading a
file and ensure that switching to octet restores the binary mode.
After report by Mike Elston.
TEST: Avoid non-termination if there is an error.
TEST: Resolve timing issues in test_proxy.pl
FIXED: http_stop_server/2 to avoid leaking socket handles for
connections accepted during shutdown.
FIXED: Ping and pong frames may contain non-utf8 “Application Data”

Package libedit

MODIFIED: Don’t do any signal-handling if O_SIGNALS is disabled

Package mqi

FIXED: Residual constraints on variables are now returned in a special
binding variable called ‘$residuals’ MQI Prolog change only, no
changes to the language clients (e.g. the swiplserver Python library)
are required.

Usage:

with server.create_thread() as client:
```
            result = client.query("member(X, [A, B, C]),
```

put_attr(X, my_module, x).")
[{‘$residuals’: [{‘args’: [‘A’, ‘my_module’, ‘x’],
‘functor’: ‘put_attr’}], ‘X’: ‘A’, ‘A’: ‘A’, ‘B’:
‘', ‘C’: '’},
{‘$residuals’: [{‘args’: [‘B’, ‘my_module’, ‘x’],
‘functor’: ‘put_attr’}], ‘X’: ‘B’, ‘A’: ‘', ‘B’:
‘B’, ‘C’: '’},
{‘$residuals’: [{‘args’: [‘C’, ‘my_module’, ‘x’],
‘functor’: ‘put_attr’}], ‘X’: ‘C’, ‘A’: ‘', ‘B’:
'’, ‘C’: ‘C’}] == result

FIXED: If exceptions happen during serialization to JSON, MQI will
now send an exception message instead of hanging
FIXED: On a multi-user system, running the MQI test suite fails if
you’re the second user to do that. Reported by
@dmchurch
FIXED: Goals are now expanded when used in MQI as they are on the
top level. Found by @Losbarthos

Package pengines

FIXED: term//2: operator atoms for other operators must always be
embraced.
ENHANCED: Pengines waiting for a new event now wait the first second
without idling. After than they call thread_idle/2 to minimise
their footprint. This avoids garbage collections for short waits
while going into a deeper sleep mode for a long wait.
ENHANCED: term//2 for rendering terms as HTML has many new options
and provides HTML that is easier to deal with using JavaScript and CSS.

Package pldoc

DOC: Support the S*() functions for IOSTREAMS.
MODIFIED: when creating a link from a URL, do not include a punctuation
character before a space. So, http://example.com/home.html. Bla
correctly links to the html page.

Package semweb

PORT: msys2/clang64, Release, avoid unused warning

Package sgml

FIXED: Avoid illegal access to local variable (harmless)
CLEANUP: Use PATH_MAX consistently
TEST: Make test_c14n.pl tests independent from newline conventions.
TEST: Make test_sgml.pl independent from newline conventions.
ENHANCED: Avoid leaking the DTDs in the main thread on exit.

Package xpce

FIXED: PceEmacs Prolog/spy and Prolog/trace menu items to deal with
SSU (=>) rules and fix DCG (–>) rules.
ADDED: PceEmacs: Prolog mode command Set breakpoint condition.
CLEANUP: Consistently use PATH_MAX
CLEANUP: Use POSIX PATH_MAX rather than MAXPATHLEN
ADDED: file->open: allow using resource iris
ENHANCED: file->size to use information from the stream when the
file is open.
ADDED: Allow opening res:// resources.
ADDED: PceEmacs to recognise Emacs -*- Var: Value; ... -*-
syntax. For now only processes tab-width: Width;
FIXED: PceEmasc Consult selection command resulted in an error
message wrt. format/3 and url/1 terms.
CLEANUP: MinGW-11 complains on cl_hash() in gitwrite.c. Code seems
fine to me, but a simple memset() does the same trick and keeps the
compiler silent.
FIXED: GIF: Write last byte outside mask image if width is divisible
by 8.
FIXED: Buffer overflow by one byte. Avoid using alloca().
FIXED: Read outside object.
PORT: Avoid non-portable %I64d.
TEST: Make test file conform to policies and include into the test set.
FIXED: edit or create the Prolog preferences file from the swipl-win
menu.
FIXED: Occasional lack of display update, notably in the graphical
debugger. This fix is a work-around that disables an early abort of the
repaint cycle if a new event arrives. It is not clear why this fixes
the redraw issue. This needs to be investigated further. Applications
that wish the old behaviour can use send(@display_manager, test_queue, @on).
FIXED: Delay geometry request for windows with a given geometry to
happen after processing the MapNotify event (X11 only). This seems to
avoid a 5 sec delay that sometimes happens in the XtGeometryRequest()
call.

nobrowser · June 24, 2022, 7:09am

Trying to build on MacOSX , I get this some way through cmake --build:

[ 88%] Generating lib/explain.tex
cd /Users/itz/src/homebrew-personal/swipl-8.4.3/build/man && ../src/swipl -f none --no-packs -x /Users/itz/src/homebrew-personal/swipl-8.4.3/build/man/pldoc2tex -- --source=/Users/itz/src/homebrew-personal/swipl-8.4.3/man --out=lib/explain.tex --subsection --summaries "library(explain)"
gmake[2]: *** No rule to make target 'man/archive', needed by 'man/lib/prologpack.tex'.  Stop.
gmake[2]: Leaving directory '/Users/itz/src/homebrew-personal/swipl-8.4.3/build'
gmake[1]: *** [CMakeFiles/Makefile2:2879: man/CMakeFiles/core.doc.html.dir/all] Error 2
gmake[1]: Leaving directory '/Users/itz/src/homebrew-personal/swipl-8.4.3/build'
gmake: *** [Makefile:159: all] Error 2

Please ignore the homebrew reference in the path; this is just preparation for the real packaging job.
I leave the directory exactly as it is after this error, in case you have questions that can be answered by inspecting it.

jan · June 24, 2022, 7:21am

Make sure to have all dependencies installed. A full build requires libarchive as dependency. It is more than just nice to have for the final system as well as this library is used to install packs (pack_install/1).

nobrowser · June 25, 2022, 8:07am

That worked, thanks. However it is slightly complicated by the fact that Homebrew libarchive package is “keg only” i.e. not symlinked into /usr/local/{include,lib}. One has to pass explicit CPPFLAGS and LDFLAGS to the cmake config step. Maybe this could be mentioned on the swipl build page. I think it’s a wiki so when I have time I’ll try to update it myself.

Also:

the ninja based build sure gives my Mac a workout, and it is a high level Mac. A MacBook Air user who tries to follow the instructions literally may get burns on their lap.
the reason Homebrew doesn’t export libarchive is that supposedly MacOS (plus Xcode) supposedly provides its own copy, but if so clearly swipl build system can’t find it wihtout help, either.

–
Ian

jan · June 25, 2022, 2:38pm

Have a look at cmake/port/Darwin.cmake which already holds several hacks for Macports and Homebrew. Maybe you can create a PR for that? Better to do it automatically than to put it in a readme nobody reads

My M1 Macbook air does the job completely silent in a little over 30 seconds My old Intel based one takes quite a bit longer and has some moments it makes a lot of noise

nobrowser · June 25, 2022, 4:30pm

That is very interesting, indeed. But is the intention that cmake includes this file automatically? Because that doesn’t seem to happen.

–
Ian

jan · June 25, 2022, 4:36pm

But it should The Homebrew support is not that well maintained

peter.ludemann · June 25, 2022, 4:46pm

I’ve seen this occasionally in the past on my Ubuntu system … I manually created the directory (mkdir -p man/archive_ and re-ran cmake and ninja, everything was fine.

jan · June 25, 2022, 4:52pm

… except you still do not have library(archive) and thus pack_install/1 doesn’t work (except for git based packages if you have git on your PATH).

nobrowser · June 26, 2022, 4:14pm

I don’t know what changed, but now it works as expected.

My homebrew package is at the web address below [1]. Compared to the official one, it includes X11 support (via quartz), and, most important for me, exports the swi pkgconfig file, so I can install stuff like [2].

[1] homebrew-personal/swi-prolog-fixed.rb at a9d22763353bf8fe0f28637d9b798fa561293678 · nobrowser/homebrew-personal · GitHub

[2] Kiran Gopinathan / SWIPL-OCaml · GitLab

–
Ian

jan · June 26, 2022, 4:29pm

If you can get the official package updated, many Mac users will be grateful!

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Ann: SWI-Prolog 8.4.3 (stable)

SWI-Prolog Changelog since version 8.4.2

Package clib

Package clpqr

Package cpp

Package http

Package libedit

Package mqi

Package pengines

Package pldoc

Package semweb

Package sgml

Package xpce

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