* test/src/search-tests.el (test-replace-match-modification-hooks):
Delete, this is testing a functionality we can't really support.

* test/src/comp-tests.el (comp-tests-tco, comp-tests-fw-prop-1)
(comp-tests-pure): Update out of date pass names.

* lisp/treesit.el (treesit--things-around): Remove function.
(treesit-forward-sexp):
(treesit-beginning-of-thing):
(treesit-end-of-thing):
(treesit-navigate-thing):
(treesit-thing-at-point):
(treesit-outline-search): Use public version of thing-functions.
(treesit--thing-prev):
(treesit--thing-next):
(treesit--thing-at):
(treesit--navigate-thing): Make public.

* test/src/treesit-tests.el (treesit--ert-test-defun-navigation): Use
public version of thing-functions.

* src/search.c (Freplace_match): For ordering of *-change-functions.

* test/src/editfns-tests.el
(editfns-tests--before/after-change-functions): New test.
(sanity-check--message, sanity-check-change-functions-error)
(sanity-check-change-functions-check-size)
(sanity-check-change-functions-before)
(sanity-check-change-functions-after): New functions.
(sanity-check--verbose, sanity-check-change-functions-beg)
(sanity-check-change-functions-end)
(sanity-check-change-functions-buffer-size)
(sanity-check-change-functions-errors): New vars.

Previously, a unibyte target buffer could be put in an incorrect state
if json-insert was used to insert non-ASCII characters.

* src/json.c (Fjson_insert): Simplify.  Don't attempt to decode the data
being inserted: it is guaranteed to be correct UTF-8 and is correct for
both unibyte and multibyte buffers.
* test/src/json-tests.el (json-serialize/roundtrip)
(json-serialize/roundtrip-scalars): Extend tests.

* test/src/json-tests.el (json-parse-string/object):
Duplicated object keys are now retained in alist and plist output.
* etc/NEWS: Mention it.

* src/json.c (json_parse_value): Generate a plain parse error.
* test/src/json-tests.el (json-parse-string/short): Adapt test.

Speed up JSON parsing substantially by only UTF-8-parsing string
literals and only exactly once.  Previously, json-parse-string always
first parsed the entire input and copied it to a new string, and then
validated each string literal twice.

We no longer create an extra new string when interning an alist key,
nor do we garble plist keys with Unicode characters.

* src/lread.c (intern_c_multibyte): New.
* src/json.c (json_encode): Remove.
(utf8_error): New.
(json_parse_string): Faster and more careful UTF-8 decoding.
Create and return a new multibyte string or symbol without extra
decoding.  All callers adapted.
(Fjson_parse_string): Skip expensive input pre-decoding.
* test/src/json-tests.el (json-parse-string/object-unicode-keys)
(json-parse-string/short): New.
(json-parse-string/string, json-parse-string/invalid-unicode):
Adapt tests.
* etc/NEWS: Mentioned change in errors.

* lisp/progmodes/sh-script.el (sh--json-read): Remove.
(sh-shellcheck-flymake): Call json-parse-buffer directly.
* test/src/json-tests.el: Don't check for function availability.

It is in general at least 2x faster than the old encoder and does not
depend on any external library.  Using our own code also gives us
control over translation details: for example, we now have full
bignum support and tighter float formatting.

* src/json.c (json_delete, json_initialized, init_json_functions)
(json_malloc, json_free, init_json, json_out_of_memory)
(json_releae_object, check_string_without_embedded_nulls, json_check)
(json_check_utf8, lisp_to_json_nonscalar_1, lisp_to_json_nonscalar)
(lisp_to_json, json_available_p, ensure_json_available, json_insert)
(json_handle_nonlocal_exit, json_insert_callback):
Remove.  Remaining uses updated.
* src/json.c (json_out_t, symset_t, struct symset_tbl)
(symset_size, make_symset_table, push_symset, pop_symset)
(cleanup_symset_tables, symset_hash, symset_expand, symset_add)
(json_out_grow_buf, cleanup_json_out, json_make_room, JSON_OUT_STR)
(json_out_str, json_out_byte, json_out_fixnum, string_not_unicode)
(json_plain_char, json_out_string, json_out_nest, json_out_unnest)
(json_out_object_cons, json_out_object_hash), json_out_array)
(json_out_float, json_out_bignum, json_out_something)
(json_out_to_string, json_serialize): New.
(Fjson_serialize, Fjson_insert):
New JSON encoder implementation.
* test/src/json-tests.el (json-serialize/object-with-duplicate-keys)
(json-serialize/string): Update tests.