vim-patch:8.1.0149: session is wrong with multiple tabs when :lcd was used

Problem:    The generated sessions file does not restore tabs properly if :lcd
            was used in one of them.
Solution:   Create the tab pages before setting the directory. (Yee Cheng
            Chin, closes vim/vim#3152)
26d4b896a7

src/nvim/ex_docmd.c

@@ -4769,10 +4769,8 @@ static void ex_abclear(exarg_T *eap)
 
 static void ex_autocmd(exarg_T *eap)
 {
-  /*
+  // Disallow autocommands from .exrc and .vimrc in current
-   * Disallow auto commands from .exrc and .vimrc in current
+  // directory for security reasons.
-   * directory for security reasons.
-   */
   if (secure) {
     secure = 2;
     eap->errmsg = e_curdir;

src/nvim/ex_session.c

@@ -526,8 +526,12 @@ static int makeopens(FILE *fd, char_u *dirnow)
     }
   }
 
-  // Close all windows but one.
+  // Close all windows and tabs but one.
   PUTLINE_FAIL("silent only");
+  if ((ssop_flags & SSOP_TABPAGES)
+      && put_line(fd, "silent tabonly") == FAIL) {
+    return FAIL;
+  }
 
   //
   // Now a :cd command to the session directory or the current directory
@@ -606,13 +610,34 @@ static int makeopens(FILE *fd, char_u *dirnow)
   //
   tab_firstwin = firstwin;      // First window in tab page "tabnr".
   tab_topframe = topframe;
+  if ((ssop_flags & SSOP_TABPAGES)) {
+    // Similar to ses_win_rec() below, populate the tab pages first so
+    // later local options won't be copied to the new tabs.
+    for (tabnr = 1;; tabnr++) {
+      const tabpage_T *const tp = find_tabpage(tabnr);
+
+      if (tp == NULL) {  // done all tab pages
+        break;
+      }
+      if (tabnr > 1 && put_line(fd, "tabnew") == FAIL) {
+        return FAIL;
+      }
+    }
+
+    const int num_tabs = tabnr - 1;
+    if (num_tabs > 1
+        && (fprintf(fd, "tabnext -%d", num_tabs - 1) < 0
+            || put_eol(fd) == FAIL)) {
+      return FAIL;
+    }
+  }
   for (tabnr = 1;; tabnr++) {
     tabpage_T *tp = find_tabpage(tabnr);
     if (tp == NULL) {
       break;  // done all tab pages
     }
 
-    int need_tabnew = false;
+    bool need_tabnext = false;
     int cnr = 1;
 
     if ((ssop_flags & SSOP_TABPAGES)) {
@@ -624,7 +649,7 @@ static int makeopens(FILE *fd, char_u *dirnow)
         tab_topframe = tp->tp_topframe;
       }
       if (tabnr > 1) {
-        need_tabnew = true;
+        need_tabnext = true;
       }
     }
 
@@ -639,11 +664,15 @@ static int makeopens(FILE *fd, char_u *dirnow)
           && !bt_help(wp->w_buffer)
           && !bt_nofile(wp->w_buffer)
           ) {
-        if (fputs(need_tabnew ? "tabedit " : "edit ", fd) < 0
+        if (need_tabnext && put_line(fd, "tabnext") == FAIL) {
+          return FAIL;
+        }
+        need_tabnext = false;
+
+        if (fputs("edit ", fd) < 0
             || ses_fname(fd, wp->w_buffer, &ssop_flags, true) == FAIL) {
           return FAIL;
         }
-        need_tabnew = false;
         if (!wp->w_arg_idx_invalid) {
           edited_win = wp;
         }
@@ -652,7 +681,7 @@ static int makeopens(FILE *fd, char_u *dirnow)
     }
 
     // If no file got edited create an empty tab page.
-    if (need_tabnew && put_line(fd, "tabnew") == FAIL) {
+    if (need_tabnext && put_line(fd, "tabnext") == FAIL) {
       return FAIL;
     }
 
@@ -775,6 +804,7 @@ static int makeopens(FILE *fd, char_u *dirnow)
   //
   if (fprintf(fd, "%s",
               "if exists('s:wipebuf') "
+              "&& len(win_findbuf(s:wipebuf)) == 0"
               "&& getbufvar(s:wipebuf, '&buftype') isnot# 'terminal'\n"
               "  silent exe 'bwipe ' . s:wipebuf\n"
               "endif\n"

src/nvim/testdir/test_mksession.vim

@@ -220,6 +220,53 @@ func Test_mksession_one_buffer_two_windows()
   call delete('Xtest_mks.out')
 endfunc
 
+func Test_mksession_lcd_multiple_tabs()
+  tabnew
+  tabnew
+  lcd
+  tabfirst
+  lcd
+  mksession! Xtest_mks.out
+  tabonly
+  source Xtest_mks.out
+  call assert_true(haslocaldir(), 'Tab 1 localdir')
+  tabnext 2
+  call assert_true(!haslocaldir(), 'Tab 2 localdir')
+  tabnext 3
+  call assert_true(haslocaldir(), 'Tab 3 localdir')
+  call delete('Xtest_mks.out')
+endfunc
+
+func Test_mksession_blank_tabs()
+  tabnew
+  tabnew
+  tabnew
+  tabnext 3
+  mksession! Xtest_mks.out
+  tabnew
+  tabnew
+  tabnext 2
+  source Xtest_mks.out
+  call assert_equal(4, tabpagenr('$'), 'session restore should restore number of tabs')
+  call assert_equal(3, tabpagenr(), 'session restore should restore the active tab')
+  call delete('Xtest_mks.out')
+endfunc
+
+func Test_mksession_blank_windows()
+  split
+  split
+  split
+  3 wincmd w
+  mksession! Xtest_mks.out
+  split
+  split
+  2 wincmd w
+  source Xtest_mks.out
+  call assert_equal(4, winnr('$'), 'session restore should restore number of windows')
+  call assert_equal(3, winnr(), 'session restore should restore the active window')
+  call delete('Xtest_mks.out')
+endfunc
+
 if has('extra_search')
 
 func Test_mksession_hlsearch()