fix: show autocmd output when F is in shortmess (#18251)

The default value of including F in 'shortmess' has the unfortunate side
effect of hiding output from autocommands. This is a common source of
confusion and often leads people to think their autocommands are not
working when they are. There is a small snippet in the docs for
'shortmess' indicating that the F flag suppresses autocmd output, but
it's not easy to find if you don't already know to look for it.

This commit removes that behavior of the F flag to make it only suppress
file info when opening a new file.

1 files changed, 6 insertions, 16 deletions

diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index 5d2d1cebde..8840813b84 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -109,6 +109,7 @@ static int read_buffer(int read_stdin, exarg_T *eap, int flags)
 {
   int retval = OK;
   linenr_T line_count;
+  bool silent = shortmess(SHM_FILEINFO);
 
   // Read from the buffer which the text is already filled in and append at
   // the end.  This makes it possible to retry when 'fileformat' or
@@ -117,7 +118,7 @@ static int read_buffer(int read_stdin, exarg_T *eap, int flags)
   retval = readfile(read_stdin ? NULL : curbuf->b_ffname,
                     read_stdin ? NULL : curbuf->b_fname,
                     line_count, (linenr_T)0, (linenr_T)MAXLNUM, eap,
-                    flags | READ_BUFFER);
+                    flags | READ_BUFFER, silent);
   if (retval == OK) {
     // Delete the binary lines.
     while (--line_count >= 0) {
@@ -162,6 +163,7 @@ int open_buffer(int read_stdin, exarg_T *eap, int flags)
   bufref_T old_curbuf;
   long old_tw = curbuf->b_p_tw;
   int read_fifo = false;
+  bool silent = shortmess(SHM_FILEINFO);
 
   // The 'readonly' flag is only set when BF_NEVERLOADED is being reset.
   // When re-entering the same buffer, it should not change, because the
@@ -212,7 +214,6 @@ int open_buffer(int read_stdin, exarg_T *eap, int flags)
   curwin->w_valid = 0;
 
   if (curbuf->b_ffname != NULL) {
-    int old_msg_silent = msg_silent;
 #ifdef UNIX
     int save_bin = curbuf->b_p_bin;
     int perm;
@@ -231,13 +232,10 @@ int open_buffer(int read_stdin, exarg_T *eap, int flags)
       curbuf->b_p_bin = true;
     }
 #endif
-    if (shortmess(SHM_FILEINFO)) {
-      msg_silent = 1;
-    }
 
     retval = readfile(curbuf->b_ffname, curbuf->b_fname,
                       (linenr_T)0, (linenr_T)0, (linenr_T)MAXLNUM, eap,
-                      flags | READ_NEW | (read_fifo ? READ_FIFO : 0));
+                      flags | READ_NEW | (read_fifo ? READ_FIFO : 0), silent);
 #ifdef UNIX
     if (read_fifo) {
       curbuf->b_p_bin = save_bin;
@@ -246,7 +244,6 @@ int open_buffer(int read_stdin, exarg_T *eap, int flags)
       }
     }
 #endif
-    msg_silent = old_msg_silent;
 
     // Help buffer is filtered.
     if (bt_help(curbuf)) {
@@ -262,7 +259,7 @@ int open_buffer(int read_stdin, exarg_T *eap, int flags)
     curbuf->b_p_bin = true;
     retval = readfile(NULL, NULL, (linenr_T)0,
                       (linenr_T)0, (linenr_T)MAXLNUM, NULL,
-                      flags | (READ_NEW + READ_STDIN));
+                      flags | (READ_NEW + READ_STDIN), silent);
     curbuf->b_p_bin = save_bin;
     if (retval == OK) {
       retval = read_buffer(true, eap, flags);
@@ -903,14 +900,7 @@ void handle_swap_exists(bufref_T *old_curbuf)
       buf = old_curbuf->br_buf;
     }
     if (buf != NULL) {
-      int old_msg_silent = msg_silent;
-
-      if (shortmess(SHM_FILEINFO)) {
-        msg_silent = 1;  // prevent fileinfo message
-      }
       enter_buffer(buf);
-      // restore msg_silent, so that the command line will be shown
-      msg_silent = old_msg_silent;
 
       if (old_tw != curbuf->b_p_tw) {
         check_colorcolumn(curwin);
@@ -5611,7 +5601,7 @@ bool buf_contents_changed(buf_T *buf)
   if (ml_open(curbuf) == OK
       && readfile(buf->b_ffname, buf->b_fname,
                   (linenr_T)0, (linenr_T)0, (linenr_T)MAXLNUM,
-                  &ea, READ_NEW | READ_DUMMY) == OK) {
+                  &ea, READ_NEW | READ_DUMMY, false) == OK) {
     // compare the two files line by line
     if (buf->b_ml.ml_line_count == curbuf->b_ml.ml_line_count) {
       differ = false;