vim-patch:8.2.1384: no ATTENTION prompt for :vimgrep first match file

Problem:    No ATTENTION prompt for :vimgrep first match file.
Solution:   When there is an existing swap file do not keep the dummy buffer.
            (closes vim/vim#6649)
8ce4b7ed85

src/nvim/quickfix.c

@@ -5068,6 +5068,20 @@ static void vgr_jump_to_match(qf_info_T *qi, int forceit, int *redraw_for_dummy,
   }
 }
 
+// Return true if "buf" had an existing swap file, the current swap file does
+// not end in ".swp".
+static bool existing_swapfile(const buf_T *buf)
+  FUNC_ATTR_NONNULL_ALL FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
+{
+  if (buf->b_ml.ml_mfp != NULL) {
+    const char_u *const fname = buf->b_ml.ml_mfp->mf_fname;
+    const size_t len = STRLEN(fname);
+
+    return fname[len - 1] != 'p' || fname[len - 2] != 'w';
+  }
+  return false;
+}
+
 // ":vimgrep {pattern} file(s)"
 // ":vimgrepadd {pattern} file(s)"
 // ":lvimgrep {pattern} file(s)"
@@ -5225,7 +5239,9 @@ void ex_vimgrep(exarg_T *eap)
           if (!found_match) {
             wipe_dummy_buffer(buf, dirname_start);
             buf = NULL;
-          } else if (buf != first_match_buf || (flags & VGR_NOJUMP)) {
+          } else if (buf != first_match_buf
+                     || (flags & VGR_NOJUMP)
+                     || existing_swapfile(buf)) {
             unload_dummy_buffer(buf, dirname_start);
             // Keeping the buffer, remove the dummy flag.
             buf->b_flags &= ~BF_DUMMY;

src/nvim/testdir/runtest.vim

@@ -78,6 +78,9 @@ set encoding=utf-8
 let s:test_script_fname = expand('%')
 au! SwapExists * call HandleSwapExists()
 func HandleSwapExists()
+  if exists('g:ignoreSwapExists')
+    return
+  endif
   " Ignore finding a swap file for the test script (the user might be
   " editing it and do ":make test_name") and the output file.
   " Report finding another swap file and chose 'q' to avoid getting stuck.

src/nvim/testdir/test_quickfix.vim

@@ -2568,6 +2568,26 @@ func Test_vimgrep_incsearch()
   set noincsearch
 endfunc
 
+func Test_vimgrep_existing_swapfile()
+  call writefile(['match apple with apple'], 'Xapple')
+  call writefile(['swapfile'], '.Xapple.swp')
+  let g:foundSwap = 0
+  let g:ignoreSwapExists = 1
+  augroup grep
+    au SwapExists * let foundSwap = 1 | let v:swapchoice = 'e'
+  augroup END
+  vimgrep apple Xapple
+  call assert_equal(1, g:foundSwap)
+  call assert_match('.Xapple.swo', swapname(''))
+
+  call delete('Xapple')
+  call delete('Xapple.swp')
+  augroup grep
+    au! SwapExists
+  augroup END
+  unlet g:ignoreSwapExists
+endfunc
+
 func XfreeTests(cchar)
   call s:setup_commands(a:cchar)