From 79f234499b6692cc16970b7455bc9b002242632f Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Mon, 10 Oct 2022 12:42:57 +0100
Subject: [PATCH] patch 9.0.0712: wrong column when calling setcursorcharpos()
 with zero lnum

Problem:    Wrong column when calling setcursorcharpos() with zero lnum.
Solution:   Set the line number before calling buf_charidx_to_byteidx().
            (closes #11329)
---
 src/eval.c                       | 10 +++++++---
 src/evalfunc.c                   | 26 ++++++++++++++------------
 src/testdir/test_cursor_func.vim |  6 ++++++
 3 files changed, 27 insertions(+), 15 deletions(-)

diff --git a/src/eval.c b/src/eval.c
index 8df374a..cbd4740 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -5906,10 +5906,12 @@ var2fpos(
 }
 
 /*
- * Convert list in "arg" into a position and optional file number.
- * When "fnump" is NULL there is no file number, only 3 items.
+ * Convert list in "arg" into position "psop" and optional file number "fnump".
+ * When "fnump" is NULL there is no file number, only 3 items: [lnum, col, off]
  * Note that the column is passed on as-is, the caller may want to decrement
  * it to use 1 for the first column.
+ * If "charcol" is TRUE use the column as the character index instead of the
+ * byte index.
  * Return FAIL when conversion is not possible, doesn't check the position for
  * validity.
  */
@@ -5952,6 +5954,7 @@ list2fpos(
     if (n < 0)
 	return FAIL;
     // If character position is specified, then convert to byte position
+    // If the line number is zero use the cursor line.
     if (charcol)
     {
 	buf_T	*buf;
@@ -5961,7 +5964,8 @@ list2fpos(
 	if (buf == NULL || buf->b_ml.ml_mfp == NULL)
 	    return FAIL;
 
-	n = buf_charidx_to_byteidx(buf, posp->lnum, n) + 1;
+	n = buf_charidx_to_byteidx(buf,
+		  posp->lnum == 0 ? curwin->w_cursor.lnum : posp->lnum, n) + 1;
     }
     posp->col = n;
 
diff --git a/src/evalfunc.c b/src/evalfunc.c
index cb12a46..2703865 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -3484,7 +3484,7 @@ f_copy(typval_T *argvars, typval_T *rettv)
     static void
 set_cursorpos(typval_T *argvars, typval_T *rettv, int charcol)
 {
-    long	line, col;
+    long	lnum, col;
     long	coladd = 0;
     int		set_curswant = TRUE;
 
@@ -3506,7 +3506,7 @@ set_cursorpos(typval_T *argvars, typval_T *rettv, int charcol)
 	    emsg(_(e_invalid_argument));
 	    return;
 	}
-	line = pos.lnum;
+	lnum = pos.lnum;
 	col = pos.col;
 	coladd = pos.coladd;
 	if (curswant >= 0)
@@ -3515,17 +3515,19 @@ set_cursorpos(typval_T *argvars, typval_T *rettv, int charcol)
 	    set_curswant = FALSE;
 	}
     }
-    else if ((argvars[0].v_type == VAR_NUMBER ||
-					argvars[0].v_type == VAR_STRING)
-	    && (argvars[1].v_type == VAR_NUMBER ||
-					argvars[1].v_type == VAR_STRING))
+    else if ((argvars[0].v_type == VAR_NUMBER
+					    || argvars[0].v_type == VAR_STRING)
+	    && (argvars[1].v_type == VAR_NUMBER
+					   || argvars[1].v_type == VAR_STRING))
     {
-	line = tv_get_lnum(argvars);
-	if (line < 0)
+	lnum = tv_get_lnum(argvars);
+	if (lnum < 0)
 	    semsg(_(e_invalid_argument_str), tv_get_string(&argvars[0]));
+	else if (lnum == 0)
+	    lnum = curwin->w_cursor.lnum;
 	col = (long)tv_get_number_chk(&argvars[1], NULL);
 	if (charcol)
-	    col = buf_charidx_to_byteidx(curbuf, line, col) + 1;
+	    col = buf_charidx_to_byteidx(curbuf, lnum, col) + 1;
 	if (argvars[2].v_type != VAR_UNKNOWN)
 	    coladd = (long)tv_get_number_chk(&argvars[2], NULL);
     }
@@ -3534,10 +3536,10 @@ set_cursorpos(typval_T *argvars, typval_T *rettv, int charcol)
 	emsg(_(e_invalid_argument));
 	return;
     }
-    if (line < 0 || col < 0 || coladd < 0)
+    if (lnum < 0 || col < 0 || coladd < 0)
 	return;		// type error; errmsg already given
-    if (line > 0)
-	curwin->w_cursor.lnum = line;
+    if (lnum > 0)
+	curwin->w_cursor.lnum = lnum;
     if (col > 0)
 	curwin->w_cursor.col = col - 1;
     curwin->w_cursor.coladd = coladd;
diff --git a/src/testdir/test_cursor_func.vim b/src/testdir/test_cursor_func.vim
index d5f0ac7..d2685ed 100644
--- a/src/testdir/test_cursor_func.vim
+++ b/src/testdir/test_cursor_func.vim
@@ -399,8 +399,14 @@ func Test_setcursorcharpos()
   normal G
   call setcursorcharpos([1, 1])
   call assert_equal([1, 1], [line('.'), col('.')])
+
   call setcursorcharpos([2, 7, 0])
   call assert_equal([2, 9], [line('.'), col('.')])
+  call setcursorcharpos([0, 7, 0])
+  call assert_equal([2, 9], [line('.'), col('.')])
+  call setcursorcharpos(0, 7, 0)
+  call assert_equal([2, 9], [line('.'), col('.')])
+
   call setcursorcharpos(3, 4)
   call assert_equal([3, 1], [line('.'), col('.')])
   call setcursorcharpos([3, 1])
-- 
2.33.0