vim-patch:8.2.3919: Vim9: wrong argument for append() results in two errors

Problem:    Vim9: wrong argument for append() results in two errors.
Solution:   Check did_emsg.  Also for setline().  Adjust the help for
            appendbufline().

https://github.com/vim/vim/commit/8b6256f6ec075cca40341e61ebc9f538b4902dd1

Co-authored-by: Bram Moolenaar <Bram@vim.org>

3 files changed, 27 insertions, 10 deletions

diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index 2cd2eed3a1..e7e44374c6 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -654,9 +654,10 @@ appendbufline({buf}, {lnum}, {text})			*appendbufline()*
 
 		For the use of {buf}, see |bufname()|.
 
-		{lnum} is used like with |append()|.  Note that using |line()|
-		would use the current buffer, not the one appending to.
-		Use "$" to append at the end of the buffer.
+		{lnum} is the line number to append below.  Note that using
+		|line()| would use the current buffer, not the one appending
+		to.  Use "$" to append at the end of the buffer.  Other string
+		values are not supported.
 
 		On success 0 is returned, on failure 1 is returned.
 
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index 5b8cbcfbb3..1200ba20ba 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -5200,6 +5200,7 @@ linenr_T tv_get_lnum_buf(const typval_T *const tv, const buf_T *const buf)
   if (tv->v_type == VAR_STRING
       && tv->vval.v_string != NULL
       && tv->vval.v_string[0] == '$'
+      && tv->vval.v_string[1] == NUL
       && buf != NULL) {
     return buf->b_ml.ml_line_count;
   }
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index c4d0604b67..cf924b1c49 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -365,20 +365,25 @@ static void f_api_info(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 /// "append(lnum, string/list)" function
 static void f_append(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
+  const int did_emsg_before = did_emsg;
   const linenr_T lnum = tv_get_lnum(&argvars[0]);
-
-  set_buffer_lines(curbuf, lnum, true, &argvars[1], rettv);
+  if (did_emsg == did_emsg_before) {
+    set_buffer_lines(curbuf, lnum, true, &argvars[1], rettv);
+  }
 }
 
 /// Set or append lines to a buffer.
 static void buf_set_append_line(typval_T *argvars, typval_T *rettv, bool append)
 {
+  const int did_emsg_before = did_emsg;
   buf_T *const buf = tv_get_buf(&argvars[0], false);
   if (buf == NULL) {
     rettv->vval.v_number = 1;  // FAIL
   } else {
     const linenr_T lnum = tv_get_lnum_buf(&argvars[1], buf);
-    set_buffer_lines(buf, lnum, append, &argvars[2], rettv);
+    if (did_emsg == did_emsg_before) {
+      set_buffer_lines(buf, lnum, append, &argvars[2], rettv);
+    }
   }
 }
 
@@ -1476,9 +1481,10 @@ static void f_dictwatcherdel(typval_T *argvars, typval_T *rettv, EvalFuncData fp
 /// "deletebufline()" function
 static void f_deletebufline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
+  const int did_emsg_before = did_emsg;
+  rettv->vval.v_number = 1;   // FAIL by default
   buf_T *const buf = tv_get_buf(&argvars[0], false);
   if (buf == NULL) {
-    rettv->vval.v_number = 1;  // FAIL
     return;
   }
   const bool is_curbuf = buf == curbuf;
@@ -1486,6 +1492,9 @@ static void f_deletebufline(typval_T *argvars, typval_T *rettv, EvalFuncData fpt
 
   linenr_T last;
   const linenr_T first = tv_get_lnum_buf(&argvars[1], buf);
+  if (did_emsg > did_emsg_before) {
+    return;
+  }
   if (argvars[2].v_type != VAR_UNKNOWN) {
     last = tv_get_lnum_buf(&argvars[2], buf);
   } else {
@@ -1494,7 +1503,6 @@ static void f_deletebufline(typval_T *argvars, typval_T *rettv, EvalFuncData fpt
 
   if (buf->b_ml.ml_mfp == NULL || first < 1
       || first > buf->b_ml.ml_line_count || last < first) {
-    rettv->vval.v_number = 1;  // FAIL
     return;
   }
 
@@ -1547,6 +1555,7 @@ static void f_deletebufline(typval_T *argvars, typval_T *rettv, EvalFuncData fpt
     curwin = curwin_save;
     VIsual_active = save_VIsual_active;
   }
+  rettv->vval.v_number = 0;  // OK
 }
 
 /// "did_filetype()" function
@@ -2581,9 +2590,12 @@ static void get_buffer_lines(buf_T *buf, linenr_T start, linenr_T end, int retli
 /// "getbufline()" function
 static void f_getbufline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
+  const int did_emsg_before = did_emsg;
   buf_T *const buf = tv_get_buf_from_arg(&argvars[0]);
-
   const linenr_T lnum = tv_get_lnum_buf(&argvars[1], buf);
+  if (did_emsg > did_emsg_before) {
+    return;
+  }
   const linenr_T end = (argvars[2].v_type == VAR_UNKNOWN
                         ? lnum
                         : tv_get_lnum_buf(&argvars[2], buf));
@@ -7636,8 +7648,11 @@ static void f_setfperm(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 /// "setline()" function
 static void f_setline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
+  const int did_emsg_before = did_emsg;
   linenr_T lnum = tv_get_lnum(&argvars[0]);
-  set_buffer_lines(curbuf, lnum, false, &argvars[1], rettv);
+  if (did_emsg == did_emsg_before) {
+    set_buffer_lines(curbuf, lnum, false, &argvars[1], rettv);
+  }
 }
 
 /// "setpos()" function