vim-patch:8.2.4980: when 'shortmess' contains 'A' loading session may still warn (#18636)

Problem:    When 'shortmess' contains 'A' loading a session may still warn for
            an existing swap file. (Melker Österberg)
Solution:   Keep the 'A' flag to 'shortmess' in the session file.
            (closes vim/vim#10443)
https://github.com/vim/vim/commit/aaadb5b6f76ea03e5eb460121f3dbf46ad04ce50

Use readfile() with "B" flag in test as readblob() needs patch 8.2.2343.

1 files changed, 7 insertions, 2 deletions

diff --git a/src/nvim/ex_session.c b/src/nvim/ex_session.c
index 7eef6707dd..dfdb8c1eac 100644
--- a/src/nvim/ex_session.c
+++ b/src/nvim/ex_session.c
@@ -598,9 +598,14 @@ static int makeopens(FILE *fd, char_u *dirnow)
     PUTLINE_FAIL("let s:shortmess_save = &shortmess");
   }
 
-  // Now save the current files, current buffer first.
-  PUTLINE_FAIL("set shortmess=aoO");
+  // set 'shortmess' for the following.  Add the 'A' flag if it was there
+  PUTLINE_FAIL("if &shortmess =~ 'A'");
+  PUTLINE_FAIL("  set shortmess=aoOA");
+  PUTLINE_FAIL("else");
+  PUTLINE_FAIL("  set shortmess=aoO");
+  PUTLINE_FAIL("endif");
 
+  // Now save the current files, current buffer first.
   // 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).