* doc/lispref/commands.texi (Using Interactive): Document the
extended `interactive' form.
* doc/lispref/loading.texi (Autoload): Document list-of-modes
form.

* lisp/emacs-lisp/autoload.el (make-autoload): Pick the list of
modes from `interactive' out of the functions.

* lisp/emacs-lisp/bytecomp.el (byte-compile-lambda): Allow for the
extended `interactive' form.

* src/callint.c (Finteractive): Document the extended form.

* src/data.c (Finteractive_form): Return the interactive form in
the old format (even when there's an extended `interactive') to
avoid having other parts of Emacs be aware of this.
(Fcommand_modes): New defun.

* src/emacs-module.c (GCALIGNED_STRUCT): Allow for modules to
return command modes.

* src/lisp.h: New function module_function_command_modes.

Run "TZ=UTC0 admin/update-copyright".

When creating multibyte or unibyte strings, we should guarantee the
following invariants:

- When creating empty strings, a NULL data pointer should be allowed.
  This often arises in practice if the string length isn't known in
  advance, and we don't want to unnecessarily trigger undefined
  behavior.  Since functions like memcpy might not accept NULL
  pointers, use the canonical empty string objects in this case.

- Nonzero strings should be guaranteed to be unique and mutable.
  These are the same guarantees expected from Lisp functions such as
  'make-string' or 'unibyte-string'.  On the other hand, empty strings
  might not be unique.

* src/emacs-module.c (module_make_string)
(module_make_unibyte_string): Correctly handle empty strings.

* test/src/emacs-module-resources/mod-test.c (Fmod_test_make_string):
New test function.
(emacs_module_init): Expose it.

* test/src/emacs-module-tests.el (mod-test-make-string/empty)
(mod-test-make-string/nonempty): New unit tests.

* doc/lispref/internals.texi (Module Values): Document properties and
corner cases for strings.

* src/emacs-module.c (finalize_runtime_unwind): Don't finalize initial
environment twice.

* test/src/emacs-module-resources/mod-test.c (emacs_module_init):
Allocate lots of values during module initialization to trigger the
bug.

We used to store module runtime and environment pointers in the static
lists Vmodule_runtimes and Vmodule_environments.  However, this is
incorrect because these objects have to be kept per-thread.  With this
naive approach, interleaving module function calls in separate threads
leads to environments being removed in the wrong order, which in turn
can cause local module values to be incorrectly garbage-collected.
The fix isn't completely trivial: specbinding the lists wouldn't work
either, because then the garbage collector wouldn't find the
environments in other threads than the current ones, again leading to
objects being garbage-collected incorrectly.  While introducing custom
pseudovector types would fix this, it's simpler to put the runtime and
environment pointers into the specbinding list as new specbinding
kinds.  This works since we need to unwind them anyway, and we only
ever treat the lists as a stack.  The thread switching machinery
ensures that the specbinding lists are thread-local, and that all
elements of the specbinding lists in all threads are marked during
garbage collection.

Module assertions now have to walk the specbinding list for the
current thread, which is more correct since they now only find
environments for the current thread.  As a result, we can now remove
the faulty Vmodule_runtimes and Vmodule_environments variables
entirely.

Also add a unit test that exemplifies the problem.  It interleaves two
module calls in two threads so that the first call ends while the
second one is still active.  Without this change, this test triggers
an assertion failure.

* src/lisp.h (enum specbind_tag): Add new tags for module runtimes and
environments.

* src/eval.c (record_unwind_protect_module): New function to record a
module object in the specpdl list.
(do_one_unbind): Unwind module objects.
(backtrace_eval_unrewind, default_toplevel_binding, lexbound_p)
(Fbacktrace__locals): Deal with new specbinding types.
(mark_specpdl): Mark module environments as needed.

* src/alloc.c (garbage_collect): Remove call to 'mark-modules'.
Garbage collection of module values is now handled as part of marking
the specpdl of each thread.

* src/emacs-module.c (Fmodule_load, funcall_module): Use specpdl to
record module runtimes and environments.
(module_assert_runtime, module_assert_env, value_to_lisp): Walk
through specpdl list instead of list variables.
(mark_module_environment): Rename from 'mark_modules'.  Don't attempt
to walk though current thread's environments only, since that would
miss other threads.
(initialize_environment, finalize_environment): Don't change
Vmodule_environments variable; environments are now in the specpdl
list.
(finalize_environment_unwind, finalize_runtime_unwind): Make 'extern'
since do_one_unbind now calls them.
(finalize_runtime_unwind): Don't change Vmodule_runtimes variable;
runtimes are now in the specpdl list.
(syms_of_module): Remove Vmodule_runtimes and Vmodule_environments.

* test/data/emacs-module/mod-test.c (Fmod_test_funcall): New test
function.
(emacs_module_init): Bind it.

* test/src/emacs-module-tests.el (emacs-module-tests--variable): New
helper type to guard access to state in a thread-safe way.
(emacs-module-tests--wait-for-variable)
(emacs-module-tests--change-variable): New helper functions.
(emacs-module-tests/interleaved-threads): New unit test.

* src/emacs-module.c: Fix the name of the .h file in the comments.

* doc/lispref/internals.texi (Module Values): Document
make_unibyte_string (bug#34873).

* src/emacs-module.c (module_make_unibyte_string): New function.
(initialize_environment): Export it.

* src/module-env-25.h: Define it.

* test/data/emacs-module/mod-test.c (Fmod_test_return_unibyte):
Test it.

* test/src/emacs-module-tests.el (module/unibyte): Test it.

* src/module-env-28.h: Add field for 'make_interactive' function.

* src/emacs-module.c (Lisp_Module_Function): Add new field holding the
interactive form.
(allocate_module_function): Adapt to structure layout change.
(module_make_interactive, module_function_interactive_form): New
functions.
(initialize_environment): Use them.

* src/eval.c (Fcommandp):
* src/data.c (Finteractive_form): Also handle interactive module
functions.

* test/data/emacs-module/mod-test.c (Fmod_test_identity): New test
function.
(emacs_module_init): Create two interactive module test functions.

* test/src/emacs-module-tests.el (module/interactive/return-t)
(module/interactive/return-t-int, module/interactive/identity):
New unit tests.

* doc/lispref/internals.texi (Module Functions): Document new
function.  Rework paragraph about wrapping module functions, as the
example no longer applies.

* etc/NEWS: Document new facility.

* configure.ac: Use AC_CHECK_FUNCS_ONCE for __lsan_ignore_object.
* src/buffer.c, src/data.c, src/emacs-module.c, src/regex-emacs.c:
* src/search.c: Use __lsan_ignore_object unconditionally, and don’t
include sanitizer/lsan_interface.h.
* src/lisp.h (__lsan_ignore_object): Provide a dummy in the
typical case where leak sanitization is not available.

* configure.ac: Add check for __lsan_ignore_object.

* src/buffer.c (enlarge_buffer_text):
* src/data.c (make_blv):
* src/emacs-module.c (Fmodule_load, initialize_environment):
* src/regex-emacs.c (regex_compile):
* src/search.c (newline_cache_on_off): Use new configuration macro.