1 files changed, 41 insertions, 25 deletions

diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index 47e23b6e80..3130747e08 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -8810,11 +8810,12 @@ makeopens (
         && buf->b_fname != NULL
         && buf->b_p_bl) {
       if (fprintf(fd, "badd +%" PRId64 " ",
-                  buf->b_wininfo == NULL ?
-                    (int64_t)1L :
-                    (int64_t)buf->b_wininfo->wi_fpos.lnum) < 0
-          || ses_fname(fd, buf, &ssop_flags) == FAIL)
+                  buf->b_wininfo == NULL
+                  ? (int64_t)1L
+                  : (int64_t)buf->b_wininfo->wi_fpos.lnum) < 0
+          || ses_fname(fd, buf, &ssop_flags, true) == FAIL) {
         return FAIL;
+      }
     }
   }
 
@@ -8885,11 +8886,13 @@ makeopens (
           && !bt_nofile(wp->w_buffer)
           ) {
         if (fputs(need_tabnew ? "tabedit " : "edit ", fd) < 0
-            || ses_fname(fd, wp->w_buffer, &ssop_flags) == FAIL)
+            || ses_fname(fd, wp->w_buffer, &ssop_flags, true) == FAIL) {
           return FAIL;
-        need_tabnew = FALSE;
-        if (!wp->w_arg_idx_invalid)
+        }
+        need_tabnew = false;
+        if (!wp->w_arg_idx_invalid) {
           edited_win = wp;
+        }
         break;
       }
     }
@@ -8933,6 +8936,8 @@ makeopens (
     // resized when moving between windows.
     // Do this before restoring the view, so that the topline and the
     // cursor can be set.  This is done again below.
+    // winminheight and winminwidth need to be set to avoid an error if the
+    // user has set winheight or winwidth.
     if (put_line(fd, "set winminheight=1 winminwidth=1 winheight=1 winwidth=1")
         == FAIL) {
       return FAIL;
@@ -9221,24 +9226,35 @@ put_view (
     if (wp->w_buffer->b_ffname != NULL
         && (!bt_nofile(wp->w_buffer) || wp->w_buffer->terminal)
         ) {
-      /*
-       * Editing a file in this buffer: use ":edit file".
-       * This may have side effects! (e.g., compressed or network file).
-       */
-      if (fputs("edit ", fd) < 0
-          || ses_fname(fd, wp->w_buffer, flagp) == FAIL)
+      // Editing a file in this buffer: use ":edit file".
+      // This may have side effects! (e.g., compressed or network file).
+      //
+      // Note, if a buffer for that file already exists, use :badd to
+      // edit that buffer, to not lose folding information (:edit resets
+      // folds in other buffers)
+      if (fputs("if bufexists('", fd) < 0
+          || ses_fname(fd, wp->w_buffer, flagp, false) == FAIL
+          || fputs("') | buffer ", fd) < 0
+          || ses_fname(fd, wp->w_buffer, flagp, false) == FAIL
+          || fputs(" | else | edit ", fd) < 0
+          || ses_fname(fd, wp->w_buffer, flagp, false) == FAIL
+          || fputs(" | endif", fd) < 0
+          || put_eol(fd) == FAIL) {
         return FAIL;
+      }
     } else {
-      /* No file in this buffer, just make it empty. */
-      if (put_line(fd, "enew") == FAIL)
+      // No file in this buffer, just make it empty.
+      if (put_line(fd, "enew") == FAIL) {
         return FAIL;
+      }
       if (wp->w_buffer->b_ffname != NULL) {
-        /* The buffer does have a name, but it's not a file name. */
+        // The buffer does have a name, but it's not a file name.
         if (fputs("file ", fd) < 0
-            || ses_fname(fd, wp->w_buffer, flagp) == FAIL)
+            || ses_fname(fd, wp->w_buffer, flagp, true) == FAIL) {
           return FAIL;
+        }
       }
-      do_cursor = FALSE;
+      do_cursor = false;
     }
   }
 
@@ -9389,12 +9405,10 @@ ses_arglist (
   return OK;
 }
 
-/*
- * Write a buffer name to the session file.
- * Also ends the line.
- * Returns FAIL if writing fails.
- */
-static int ses_fname(FILE *fd, buf_T *buf, unsigned *flagp)
+/// Write a buffer name to the session file.
+/// Also ends the line, if "add_eol" is true.
+/// Returns FAIL if writing fails.
+static int ses_fname(FILE *fd, buf_T *buf, unsigned *flagp, bool add_eol)
 {
   char_u      *name;
 
@@ -9411,8 +9425,10 @@ static int ses_fname(FILE *fd, buf_T *buf, unsigned *flagp)
     name = buf->b_sfname;
   else
     name = buf->b_ffname;
-  if (ses_put_fname(fd, name, flagp) == FAIL || put_eol(fd) == FAIL)
+  if (ses_put_fname(fd, name, flagp) == FAIL
+      || (add_eol && put_eol(fd) == FAIL)) {
     return FAIL;
+  }
   return OK;
 }