vim-patch:7.4.579 #2652

Problem:    Wrong cursor positioning when 'linebreak' is set and lines wrap.
Solution:   (Christian Brabandt)

https://github.com/vim/vim/commit/v7-4-579

See https://groups.google.com/d/msg/vim_dev/Eh3N9L68Ajw/4dB5x1RTQJQJ

3 files changed, 46 insertions, 12 deletions

diff --git a/src/nvim/charset.c b/src/nvim/charset.c
index da65839353..b93eafbf60 100644
--- a/src/nvim/charset.c
+++ b/src/nvim/charset.c
@@ -1049,29 +1049,54 @@ int win_lbr_chartabsize(win_T *wp, char_u *line, char_u *s, colnr_T col, int *he
   added = 0;
 
   if ((*p_sbr != NUL || wp->w_p_bri) && wp->w_p_wrap && (col != 0)) {
-    numberextra = win_col_off(wp);
+    colnr_T sbrlen = 0;
+    int numberwidth = win_col_off(wp);
+
+    numberextra = numberwidth;
     col += numberextra + mb_added;
 
     if (col >= (colnr_T)wp->w_width) {
       col -= wp->w_width;
       numberextra = wp->w_width - (numberextra - win_col_off2(wp));
-      if (numberextra > 0) {
+      if (col >= numberextra && numberextra > 0) {
         col %= numberextra;
       }
       if (*p_sbr != NUL) {
-        colnr_T sbrlen = (colnr_T)MB_CHARLEN(p_sbr);
-        if (col >= sbrlen)
+        sbrlen = (colnr_T)MB_CHARLEN(p_sbr);
+        if (col >= sbrlen) {
           col -= sbrlen;
+        }
       }
-      if (numberextra > 0) {
-        col = col % numberextra;
+      if (col >= numberextra && numberextra > 0) {
+        col %= numberextra;
+      } else if (col > 0 && numberextra > 0) {
+        col += numberwidth - win_col_off2(wp);
       }
+
+      numberwidth -= win_col_off2(wp);
     }
 
-    if ((col == 0) || (col + size > (colnr_T)wp->w_width)) {
+    if (col == 0 || (col + size + sbrlen > (colnr_T)wp->w_width)) {
       added = 0;
-      if (*p_sbr != NUL)
-        added += vim_strsize(p_sbr);
+
+      if (*p_sbr != NUL) {
+        if (size + sbrlen + numberwidth > (colnr_T)wp->w_width) {
+          // Calculate effective window width.
+          int width = (colnr_T)wp->w_width - sbrlen - numberwidth;
+          int prev_width = col ? ((colnr_T)wp->w_width - (sbrlen + col)) : 0;
+          if (width == 0) {
+            width = (colnr_T)wp->w_width;
+          }
+          added += ((size - prev_width) / width) * vim_strsize(p_sbr);
+          if ((size - prev_width) % width) {
+            // Wrapped, add another length of 'sbr'.
+            added += vim_strsize(p_sbr);
+          }
+        } else {
+          added += vim_strsize(p_sbr);
+        }
+      }
+
       if (wp->w_p_bri)
         added += get_breakindent_win(wp, line);
 
diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index 4442e7bba6..7a6e3c59c0 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -2063,6 +2063,7 @@ win_line (
   unsigned off;                         /* offset in ScreenLines/ScreenAttrs */
   int c = 0;                            /* init for GCC */
   long vcol = 0;                        /* virtual column (for tabs) */
+  long vcol_sbr = -1;                   // virtual column after showbreak
   long vcol_prev = -1;                  /* "vcol" of previous character */
   char_u      *line;                    /* current line */
   char_u      *ptr;                     /* current position in "line" */
@@ -2761,6 +2762,7 @@ win_line (
           n_extra = (int)STRLEN(p_sbr);
           char_attr = hl_attr(HLF_AT);
           need_showbreak = FALSE;
+          vcol_sbr = vcol + MB_CHARLEN(p_sbr);
           /* Correct end of highlighted area for 'showbreak',
            * required when 'linebreak' is also set. */
           if (tocol == vcol)
@@ -3361,9 +3363,16 @@ win_line (
          */
         if (c == TAB && (!wp->w_p_list || lcs_tab1)) {
           int tab_len = 0;
-          /* tab amount depends on current column */
+          long vcol_adjusted = vcol;  // removed showbreak length
+          // Only adjust the tab_len, when at the first column after the
+          // showbreak value was drawn.
+          if (*p_sbr != NUL && vcol == vcol_sbr && wp->w_p_wrap) {
+            vcol_adjusted = vcol - MB_CHARLEN(p_sbr);
+          }
+          // tab amount depends on current column
           tab_len = (int)wp->w_buffer->b_p_ts
-                    - vcol % (int)wp->w_buffer->b_p_ts - 1;
+                    - vcol_adjusted % (int)wp->w_buffer->b_p_ts - 1;
+
           if (!wp->w_p_lbr || !wp->w_p_list) {
             n_extra = tab_len;
           } else {
diff --git a/src/nvim/version.c b/src/nvim/version.c
index 3a95e9373a..d9bdafbb68 100644
--- a/src/nvim/version.c
+++ b/src/nvim/version.c
@@ -221,7 +221,7 @@ static int included_patches[] = {
   //582,
   //581 NA
   580,
-  //579,
+  579,
   578,
   577,
   576,