patch 9.1.0430: getregionpos() doesn't handle one char selection

Problem:  getregionpos() doesn't handle one char selection.
Solution: Handle startspaces differently when is_oneChar is set.
          Also add a test for an exclusive charwise selection with
          multibyte chars (zeertzjq)

closes: #14825

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 903205a..b65df5d 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -5793,7 +5793,6 @@
 
     for (lnum = p1.lnum; lnum <= p2.lnum; lnum++)
     {
-	struct block_def	bd;
 	pos_T			ret_p1, ret_p2;
 
 	if (region_type == MLINE)
@@ -5805,11 +5804,28 @@
 	}
 	else
 	{
+	    struct block_def	bd;
+
 	    if (region_type == MBLOCK)
 		block_prep(&oa, &bd, lnum, FALSE);
 	    else
 		charwise_block_prep(p1, p2, &bd, lnum, inclusive);
-	    if (bd.startspaces > 0)
+
+	    if (bd.is_oneChar)  // selection entirely inside one char
+	    {
+		if (region_type == MBLOCK)
+		{
+		    ret_p1.col = bd.textcol;
+		    ret_p1.coladd = bd.start_char_vcols
+					     - (bd.start_vcol - oa.start_vcol);
+		}
+		else
+		{
+		    ret_p1.col = p1.col + 1;
+		    ret_p1.coladd = p1.coladd;
+		}
+	    }
+	    else if (bd.startspaces > 0)
 	    {
 		ret_p1.col = bd.textcol;
 		ret_p1.coladd = bd.start_char_vcols - bd.startspaces;
@@ -5819,7 +5835,13 @@
 		ret_p1.col = bd.textcol + 1;
 		ret_p1.coladd = 0;
 	    }
-	    if (bd.endspaces > 0)
+
+	    if (bd.is_oneChar)  // selection entirely inside one char
+	    {
+		ret_p2.col = ret_p1.col;
+		ret_p2.coladd = ret_p1.coladd + bd.startspaces;
+	    }
+	    else if (bd.endspaces > 0)
 	    {
 		ret_p2.col = bd.textcol + bd.textlen + 1;
 		ret_p2.coladd = bd.endspaces;
diff --git a/src/ops.c b/src/ops.c
index 605a664..1dd36ab 100644
--- a/src/ops.c
+++ b/src/ops.c
@@ -2444,13 +2444,13 @@
     int			inclusive)
 {
     colnr_T startcol = 0, endcol = MAXCOL;
-    int	    is_oneChar = FALSE;
     colnr_T cs, ce;
     char_u *p;
 
     p = ml_get(lnum);
     bdp->startspaces = 0;
     bdp->endspaces = 0;
+    bdp->is_oneChar = FALSE;
     bdp->start_char_vcols = 0;
 
     if (lnum == start.lnum)
@@ -2487,7 +2487,7 @@
 		if (start.lnum == end.lnum && start.col == end.col)
 		{
 		    // Special case: inside a single char
-		    is_oneChar = TRUE;
+		    bdp->is_oneChar = TRUE;
 		    bdp->startspaces = end.coladd - start.coladd + inclusive;
 		    endcol = startcol;
 		}
@@ -2501,7 +2501,7 @@
     }
     if (endcol == MAXCOL)
 	endcol = ml_get_len(lnum);
-    if (startcol > endcol || is_oneChar)
+    if (startcol > endcol || bdp->is_oneChar)
 	bdp->textlen = 0;
     else
 	bdp->textlen = endcol - startcol + inclusive;
diff --git a/src/testdir/test_visual.vim b/src/testdir/test_visual.vim
index 8c850d1..621be29 100644
--- a/src/testdir/test_visual.vim
+++ b/src/testdir/test_visual.vim
@@ -1889,7 +1889,7 @@
           \ getregion(getpos('v'), getpos('.'), {'type': "\<C-v>" }))
     call assert_equal([
           \   [[bufnr('%'), 1, 5, 0], [bufnr('%'), 1, 5, 0]],
-          \   [[bufnr('%'), 2, 10, 1], [bufnr('%'), 2, 10, 0]],
+          \   [[bufnr('%'), 2, 10, 1], [bufnr('%'), 2, 10, 2]],
           \   [[bufnr('%'), 3, 5, 0], [bufnr('%'), 3, 5, 0]],
           \ ],
           \ getregionpos(getpos('v'), getpos('.'), {'type': "\<C-v>" }))
@@ -1900,6 +1900,7 @@
           \ ],
           \ getregionpos(getpos('v'), getpos('.'), {'type': 'v' }))
 
+    #" characterwise selection with multibyte chars
     call cursor(1, 1)
     call feedkeys("\<Esc>vj", 'xt')
     call assert_equal(['abcdefghijk«', "\U0001f1e6"],
@@ -1910,8 +1911,17 @@
           \ ],
           \ getregionpos(getpos('v'), getpos('.'), {'type': 'v' }))
 
+    set selection=exclusive
+    call feedkeys('l', 'xt')
+    call assert_equal(['abcdefghijk«', "\U0001f1e6"],
+          \ getregion(getpos('v'), getpos('.'), {'type': 'v' }))
+    call assert_equal([
+          \   [[bufnr('%'), 1, 1, 0], [bufnr('%'), 1, 13, 0]],
+          \   [[bufnr('%'), 2, 1, 0], [bufnr('%'), 2, 4, 0]],
+          \ ],
+          \ getregionpos(getpos('v'), getpos('.'), {'type': 'v' }))
+
     #" marks on multibyte chars
-    :set selection=exclusive
     call setpos("'a", [0, 1, 11, 0])
     call setpos("'b", [0, 2, 16, 0])
     call setpos("'c", [0, 2, 0, 0])
@@ -1997,6 +2007,7 @@
     call assert_equal(["c", "x\tz"],
           \ getregion(getpos('v'), getpos('.'), {'type': 'v' }))
     set selection&
+    bwipe!
 
     #" Exclusive selection 2
     new
@@ -2033,7 +2044,24 @@
     set virtualedit=all
 
     call cursor(1, 1)
-    call feedkeys("\<Esc>2lv2lj", 'xt')
+    call feedkeys("\<Esc>lv2l", 'xt')
+    call assert_equal(['  '],
+          \ getregion(getpos('v'), getpos('.'), {'type': 'v' }))
+    call assert_equal([
+          \   [[bufnr('%'), 1, 2, 0], [bufnr('%'), 1, 2, 2]],
+          \ ],
+          \ getregionpos(getpos('v'), getpos('.'), {'type': 'v' }))
+
+    call cursor(1, 1)
+    call feedkeys("\<Esc>2lv2l", 'xt')
+    call assert_equal(['  '],
+          \ getregion(getpos('v'), getpos('.'), {'type': 'v' }))
+    call assert_equal([
+          \   [[bufnr('%'), 1, 2, 1], [bufnr('%'), 1, 2, 3]],
+          \ ],
+          \ getregionpos(getpos('v'), getpos('.'), {'type': 'v' }))
+
+    call feedkeys('j', 'xt')
     call assert_equal(['      c', 'x   '],
           \ getregion(getpos('v'), getpos('.'), {'type': 'v' }))
     call assert_equal([
@@ -2043,12 +2071,33 @@
           \ getregionpos(getpos('v'), getpos('.'), {'type': 'v' }))
 
     call cursor(1, 1)
+    call feedkeys("\<Esc>6l\<C-v>2lj", 'xt')
+    call assert_equal(['  ', '  '],
+          \ getregion(getpos('v'), getpos('.'), {'type': "\<C-v>" }))
+    call assert_equal([
+          \   [[bufnr('%'), 1, 2, 5], [bufnr('%'), 1, 2, 7]],
+          \   [[bufnr('%'), 2, 2, 5], [bufnr('%'), 2, 2, 7]],
+          \ ],
+          \ getregionpos(getpos('v'), getpos('.'), {'type': "\<C-v>" }))
+
+    call cursor(1, 1)
+    call feedkeys("\<Esc>l\<C-v>2l2j", 'xt')
+    call assert_equal(['  ', '  ', '  '],
+          \ getregion(getpos('v'), getpos('.'), {'type': "\<C-v>" }))
+    call assert_equal([
+          \   [[bufnr('%'), 1, 2, 0], [bufnr('%'), 1, 2, 2]],
+          \   [[bufnr('%'), 2, 2, 0], [bufnr('%'), 2, 2, 2]],
+          \   [[bufnr('%'), 3, 0, 0], [bufnr('%'), 3, 0, 2]],
+          \ ],
+          \ getregionpos(getpos('v'), getpos('.'), {'type': "\<C-v>" }))
+
+    call cursor(1, 1)
     call feedkeys("\<Esc>2l\<C-v>2l2j", 'xt')
     call assert_equal(['  ', '  ', '  '],
           \ getregion(getpos('v'), getpos('.'), {'type': "\<C-v>" }))
     call assert_equal([
-          \   [[bufnr('%'), 1, 2, 5], [bufnr('%'), 1, 2, 0]],
-          \   [[bufnr('%'), 2, 2, 5], [bufnr('%'), 2, 2, 0]],
+          \   [[bufnr('%'), 1, 2, 1], [bufnr('%'), 1, 2, 3]],
+          \   [[bufnr('%'), 2, 2, 1], [bufnr('%'), 2, 2, 3]],
           \   [[bufnr('%'), 3, 0, 0], [bufnr('%'), 3, 0, 2]],
           \ ],
           \ getregionpos(getpos('v'), getpos('.'), {'type': "\<C-v>" }))
diff --git a/src/version.c b/src/version.c
index b2f0416..28dad45 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    430,
+/**/
     429,
 /**/
     428,