"Insert before markers" in read_and_insert_process_output properly

* src/coding.c (setup_coding_system): Initialize it.
(produce_chars, encode_coding, decode_coding_gap):
Obey it in insert_from_gap calls.
(encode_string_utf_8, decode_string_utf_8): Update the other calls
to insert_from_gap to have one new argument (false).

* src/coding.h: New field insert_before_markers.

* src/decompress.c (Fzlib_decompress_region): Here too.

* src/insdel.c (insert_from_gap):
Accept new argument BEFORE_MARKERS (bug#71525) and pass it through
to adjust_markers_for_insert.

* src/lisp.h: Update prototype.

* src/process.c (read_and_insert_process_output):
Set process_coding->insert_before_markers instead of calling
adjust_markers_for_insert.

1 files changed, 4 insertions, 3 deletions

diff --git a/src/process.c b/src/process.c
index eb526311c53..58d9f8162df 100644
--- a/src/process.c
+++ b/src/process.c
@@ -6406,6 +6406,9 @@ read_and_insert_process_output (struct Lisp_Process *p, char *buf,
   if (NILP (BVAR (XBUFFER (p->buffer), enable_multibyte_characters))
            && ! CODING_MAY_REQUIRE_DECODING (process_coding))
     {
+      /* For compatibility with the long-standing behavior of
+         internal-default-process-filter we insert before markers,
+         both here and in the 'else' branch.  */
       insert_1_both (buf, nread, nread, 0, 0, 1);
       signal_after_change (PT - nread, 0, nread);
     }
@@ -6415,6 +6418,7 @@ read_and_insert_process_output (struct Lisp_Process *p, char *buf,
       specpdl_ref count1 = SPECPDL_INDEX ();
 
       XSETBUFFER (curbuf, current_buffer);
+      process_coding->insert_before_markers = true;
       /* We cannot allow after-change-functions be run
          during decoding, because that might modify the
          buffer, while we rely on process_coding.produced to
@@ -6423,9 +6427,6 @@ read_and_insert_process_output (struct Lisp_Process *p, char *buf,
       specbind (Qinhibit_modification_hooks, Qt);
       decode_coding_c_string (process_coding,
                               (unsigned char *) buf, nread, curbuf);
-      adjust_markers_for_insert (PT, PT_BYTE,
-                                 PT + process_coding->produced_char,
-                                 PT_BYTE + process_coding->produced, true);
       unbind_to (count1, Qnil);
 
       read_process_output_set_last_coding_system (p, process_coding);