vim-patch:8.0.0255: setpos() does not use the buffer argument for all marks

Problem:    When calling setpos() with a buffer argument it often is ignored.
            (Matthew Malcomson)
Solution:   Make the buffer argument work for all marks local to a buffer.
            (neovim vim/vim#5713)  Add more tests.
f13e00b2cf

runtime/doc/eval.txt

@@ -6789,10 +6789,12 @@ setpos({expr}, {list})
 		    [bufnum, lnum, col, off, curswant]
 
 		"bufnum" is the buffer number.	Zero can be used for the
-		current buffer.  Setting the cursor is only possible for
-		the current buffer.  To set a mark in another buffer you can
-		use the |bufnr()| function to turn a file name into a buffer
-		number.
+		current buffer.  When setting an uppercase mark "bufnum" is
+		used for the mark position.  For other marks it specifies the
+		buffer to set the mark in.  You can use the |bufnr()| function
+		to turn a file name into a buffer number.
+		For setting the cursor and the ' mark "bufnum" is ignored,
+		since these are associated with a window, not a buffer.
 		Does not change the jumplist.
 
 		"lnum" and "col" are the position in the buffer.  The first

src/nvim/mark.c

@@ -106,39 +106,41 @@ int setmark_pos(int c, pos_T *pos, int fnum)
     return OK;
   }
 
+  // Can't set a mark in a non-existant buffer.
+  buf_T *buf = buflist_findnr(fnum);
+  if (buf == NULL) {
+    return FAIL;
+  }
+
   if (c == '"') {
-    RESET_FMARK(&curbuf->b_last_cursor, *pos, curbuf->b_fnum);
+    RESET_FMARK(&buf->b_last_cursor, *pos, buf->b_fnum);
     return OK;
   }
 
   /* Allow setting '[ and '] for an autocommand that simulates reading a
    * file. */
   if (c == '[') {
-    curbuf->b_op_start = *pos;
+    buf->b_op_start = *pos;
     return OK;
   }
   if (c == ']') {
-    curbuf->b_op_end = *pos;
+    buf->b_op_end = *pos;
     return OK;
   }
 
   if (c == '<' || c == '>') {
-    if (c == '<')
-      curbuf->b_visual.vi_start = *pos;
-    else
-      curbuf->b_visual.vi_end = *pos;
-    if (curbuf->b_visual.vi_mode == NUL)
-      /* Visual_mode has not yet been set, use a sane default. */
-      curbuf->b_visual.vi_mode = 'v';
+    if (c == '<') {
+      buf->b_visual.vi_start = *pos;
+    } else {
+      buf->b_visual.vi_end = *pos;
+    }
+    if (buf->b_visual.vi_mode == NUL) {
+      // Visual_mode has not yet been set, use a sane default.
+      buf->b_visual.vi_mode = 'v';
+    }
     return OK;
   }
 
-  buf_T *buf = buflist_findnr(fnum);
-  // Can't set a mark in a non-existant buffer.
-  if (buf == NULL) {
-    return FAIL;
-  }
-
   if (ASCII_ISLOWER(c)) {
     i = c - 'a';
     RESET_FMARK(buf->b_namedm + i, *pos, fnum);
@@ -358,13 +360,14 @@ pos_T *getmark_buf_fnum(buf_T *buf, int c, int changefile, int *fnum)
   } else if (c == '<' || c == '>') {  /* start/end of visual area */
     startp = &buf->b_visual.vi_start;
     endp = &buf->b_visual.vi_end;
-    if ((c == '<') == lt(*startp, *endp))
+    if (((c == '<') == lt(*startp, *endp) || endp->lnum == 0)
+        && startp->lnum != 0) {
       posp = startp;
-    else
+    } else {
       posp = endp;
-    /*
-     * For Visual line mode, set mark at begin or end of line
-     */
+    }
+
+    // For Visual line mode, set mark at begin or end of line
     if (buf->b_visual.vi_mode == 'V') {
       pos_copy = *posp;
       posp = &pos_copy;
@@ -647,8 +650,8 @@ void do_marks(exarg_T *eap)
   show_one_mark(-1, arg, NULL, NULL, false);
 }
 
-static void 
-show_one_mark (
+static void
+show_one_mark(
     int c,
     char_u *arg,
     pos_T *p,

src/nvim/testdir/test_marks.vim

@@ -24,3 +24,47 @@ function! Test_Incr_Marks()
   call assert_equal("XXX 123 123", getline(3))
   enew!
 endfunction
+
+func Test_setpos()
+  new one
+  let onebuf = bufnr('%')
+  let onewin = win_getid()
+  call setline(1, ['aaa', 'bbb', 'ccc'])
+  new two
+  let twobuf = bufnr('%')
+  let twowin = win_getid()
+  call setline(1, ['aaa', 'bbb', 'ccc'])
+
+  " for the cursor the buffer number is ignored
+  call setpos(".", [0, 2, 1, 0])
+  call assert_equal([0, 2, 1, 0], getpos("."))
+  call setpos(".", [onebuf, 3, 3, 0])
+  call assert_equal([0, 3, 3, 0], getpos("."))
+
+  call setpos("''", [0, 1, 3, 0])
+  call assert_equal([0, 1, 3, 0], getpos("''"))
+  call setpos("''", [onebuf, 2, 2, 0])
+  call assert_equal([0, 2, 2, 0], getpos("''"))
+
+  " buffer-local marks
+  for mark in ["'a", "'\"", "'[", "']", "'<", "'>"]
+    call win_gotoid(twowin)
+    call setpos(mark, [0, 2, 1, 0])
+    call assert_equal([0, 2, 1, 0], getpos(mark), "for mark " . mark)
+    call setpos(mark, [onebuf, 1, 3, 0])
+    call win_gotoid(onewin)
+    call assert_equal([0, 1, 3, 0], getpos(mark), "for mark " . mark)
+  endfor
+
+  " global marks
+  call win_gotoid(twowin)
+  call setpos("'N", [0, 2, 1, 0])
+  call assert_equal([twobuf, 2, 1, 0], getpos("'N"))
+  call setpos("'N", [onebuf, 1, 3, 0])
+  call assert_equal([onebuf, 1, 3, 0], getpos("'N"))
+
+  call win_gotoid(onewin)
+  bwipe!
+  call win_gotoid(twowin)
+  bwipe!
+endfunc