patch 8.2.4090: after restoring a session buffer order can be quite different

Problem:    After restoring a session buffer order can be quite different.
Solution:   Create buffers first. (Evgeni Chasnovski, closes #9520)

diff --git a/src/session.c b/src/session.c
index 21af90245954a3f934ca75c6b8c6cd30736586b7..68e40db80d5c2bba1a1d9678cf2e8460110e6ecc 100644 (file)
--- a/src/session.c
+++ b/src/session.c
@@ -690,6 +690,28 @@ makeopens(
     if (put_line(fd, "set shortmess=aoO") == FAIL)
        goto fail;
 
+    // Put all buffers into the buffer list.
+    // Do it very early to preserve buffer order after loading session (which
+    // can be disrupted by prior `edit` or `tabedit` calls).
+    FOR_ALL_BUFFERS(buf)
+    {
+       if (!(only_save_windows && buf->b_nwindows == 0)
+               && !(buf->b_help && !(ssop_flags & SSOP_HELP))
+#ifdef FEAT_TERMINAL
+               // Skip terminal buffers: finished ones are not useful, others
+               // will be resurrected and result in a new buffer.
+               && !bt_terminal(buf)
+#endif
+               && buf->b_fname != NULL
+               && buf->b_p_bl)
+       {
+           if (fprintf(fd, "badd +%ld ", buf->b_wininfo == NULL ? 1L
+                                          : buf->b_wininfo->wi_fpos.lnum) < 0
+                   || ses_fname(fd, buf, &ssop_flags, TRUE) == FAIL)
+               goto fail;
+       }
+    }
+
     // the global argument list
     if (ses_arglist(fd, "argglobal", &global_alist.al_ga,
                            !(ssop_flags & SSOP_CURDIR), &ssop_flags) == FAIL)
@@ -741,7 +763,11 @@ makeopens(
        // Similar to ses_win_rec() below, populate the tab pages first so
        // later local options won't be copied to the new tabs.
        FOR_ALL_TABPAGES(tp)
-           if (tp->tp_next != NULL && put_line(fd, "tabnew") == FAIL)
+           // Use `bufhidden=wipe` to remove empty "placeholder" buffers once
+           // they are not needed. This prevents creating extra buffers (see
+           // cause of patch 8.1.0829)
+           if (tp->tp_next != NULL
+                 && put_line(fd, "tabnew +setlocal\\ bufhidden=wipe") == FAIL)
                goto fail;
        if (first_tabpage->tp_next != NULL && put_line(fd, "tabrewind") == FAIL)
            goto fail;
@@ -919,29 +945,6 @@ makeopens(
     if (restore_stal && put_line(fd, "set stal=1") == FAIL)
        goto fail;
 
-    // Now put the remaining buffers into the buffer list.
-    // This is near the end, so that when 'hidden' is set we don't create extra
-    // buffers.  If the buffer was already created with another command the
-    // ":badd" will have no effect.
-    FOR_ALL_BUFFERS(buf)
-    {
-       if (!(only_save_windows && buf->b_nwindows == 0)
-               && !(buf->b_help && !(ssop_flags & SSOP_HELP))
-#ifdef FEAT_TERMINAL
-               // Skip terminal buffers: finished ones are not useful, others
-               // will be resurrected and result in a new buffer.
-               && !bt_terminal(buf)
-#endif
-               && buf->b_fname != NULL
-               && buf->b_p_bl)
-       {
-           if (fprintf(fd, "badd +%ld ", buf->b_wininfo == NULL ? 1L
-                                          : buf->b_wininfo->wi_fpos.lnum) < 0
-                   || ses_fname(fd, buf, &ssop_flags, TRUE) == FAIL)
-               goto fail;
-       }
-    }
-
     // Wipe out an empty unnamed buffer we started in.
     if (put_line(fd, "if exists('s:wipebuf') && len(win_findbuf(s:wipebuf)) == 0")
                                                                       == FAIL)

diff --git a/src/testdir/test_mksession.vim b/src/testdir/test_mksession.vim
index 301ff0514e4997075b2d853e24e8f323161ead22..494ac873bbd9cb4febe7af66cb32e521734680d9 100644 (file)
--- a/src/testdir/test_mksession.vim
+++ b/src/testdir/test_mksession.vim
@@ -362,6 +362,31 @@ func Test_mksession_buffer_count()
   set hidden&
 endfunc
 
+func Test_mksession_buffer_order()
+  %bwipe!
+  e Xfoo | e Xbar | e Xbaz | e Xqux
+  bufdo write
+  mksession! Xtest_mks.out
+
+  " Verify that loading the session preserves order of buffers
+  %bwipe!
+  source Xtest_mks.out
+
+  let s:buf_info = getbufinfo()
+  call assert_true(s:buf_info[0]['name'] =~# 'Xfoo$')
+  call assert_true(s:buf_info[1]['name'] =~# 'Xbar$')
+  call assert_true(s:buf_info[2]['name'] =~# 'Xbaz$')
+  call assert_true(s:buf_info[3]['name'] =~# 'Xqux$')
+
+  " Clean up.
+  call delete('Xfoo')
+  call delete('Xbar')
+  call delete('Xbaz')
+  call delete('Xqux')
+  call delete('Xtest_mks.out')
+  %bwipe!
+endfunc
+
 if has('extra_search')
 
 func Test_mksession_hlsearch()

diff --git a/src/version.c b/src/version.c
index 2bee440e991af1e099b481527b77f66c6277926c..b65dac3c59393a396dae3cfd4a7fe5a62fd4eb3f 100644 (file)
--- a/src/version.c
+++ b/src/version.c
@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4090,
 /**/
     4089,
 /**/